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Geo Metro Engine Questions



  • My son limped home my Geo and it has not started since. It cranks, all cylinders have good pressure, Have fuel no spark. Tested Coil and it reads good. I do not have a crank P/U. The distributor pick-up coil test good, The distributor ignitor may be the problem...I am unable to check at this time and can't find info on how to test. Is there anything else that I could check before I buy parts?
  • zaken1zaken1 Posts: 556
    Before you start testing for spark anywhere; it is essential to understand that you cannot jumper across the ignition switch on a Metro to make the engine run. There is an anti theft circuit built into this electrical system which shuts down the spark if you jumper across the ignition switch (even when the key is turned on). So you must have all the wiring connected in the stock routing.

    A> The next thing to check is to remove the distributor cap and have someone watch the rotor while the engine is being cranked. If the rotor does not turn steadily as the engine is cranked; then the timing belt has broken or slipped out of position. If the rotor does turn; then turn the crankshaft until the timing marks line up at the 6 degrees BTDC position. At that position; the tip of the rotor should either be pointing STRAIGHT UP, OR STRAIGHT DOWN. If it points anywhere else; the timing belt has jumped out of position.

    You say you have no spark; but you didn't specify the location where you found there was no spark. This can be critically important; because the spark can be blocked by something as basic as a defective ignition switch. If that were the case; and you hadn't first checked to see if there was battery supply voltage at the coil positive terminal, you could spend a fortune replacing every part in the entire ignition system, and never see any improvement. So, to do ignition diagnosis properly, and avoid needless waste of money; you need to start at the source, and then work step by step along the entire path from the battery to the spark plug..

    B> Make sure you're getting full battery power to the coil; and confirm a voltmeter reading with a large bulb (24 watt stoplight or equivalent) to be sure that the voltage is maintained when an appreciable current is being drawn from the power source. A bad test reading could come from high internal resistance in the ignition switch, or a poor connection between the battery ground cable and the engine; or between the battery ground cable and the inner fender. There MUST be a solid conection between the battery and BOTH of those points.

    C> If you get a confirmed voltage and power supply at the coil; check the igniter by connecting a good, old fasioned point dwell meter between ground and the coil negative lead. Crank the starter; and you should see a dwell reading of somewhere between 25% and 75% of the maximum number of degrees on the scale. So, if you had the dwell scale set to 8 cylinders, where 45 degrees is the maximum possible reading; you should get a reading somewhere between 11 degrees (which is about 25% of 45) and 33 degrees (which is about 75% of 45). If you use the 6 cylinder dwell scale, where 60 degrees is the maximum possible reading; your reading should be between 15 degrees and 45 degrees. It really doesn't matter which number of cylinders scale you use; it is only the PERCENTAGE of the full scale reading that we care about, and that will be the same regardless of which dwell scale is used.

    D> If the dwell meter test comes out good; then test for spark directly between the coil high voltage terminal and ground. First check the resistance of the coil to distributor cap high voltage wire with an ohmmeter. The resistance should be less than 1,000 ohms per inch of wire length (so a 12" long wire should have less than 12,000 ohms resistance, etc. If the resistance is greater than that; replace the entire set of plug wires.) Just hold the end of the coil to distributor cap wire about 1/4" to 1/2" from a metal part on the engine (with your hand at least 6 inches back from the end), and crank the motor. If there is no spark in that test and all of the previous tests were good; then either the coil is defective (or the wrong model part for this car) or the distributor pick up coil is defective (even though you said it tested good).

    E> If you have a spark at the coil, but not at the plugs; then with the distributor cap off and the rotor in place, hold the end of the coil wire next to the metal blade on the rotor while the engine is cranked. There should NOT be a spark to the rotor in this test. If there is a spark; the rotor is grounded and must be replaced.

    F> If the rotor tests good, and there is no spark to the plugs; then either the distributor cap or the plug wires are bad.

    G> Whenever there has been a lot of driving with an ignition problem; the spark plugs can build up conductive deposits which will then make the engine run badly; even after the problem is fixed. So it is always good insurance to replace the plugs.

    Please note that Metro engines are highly sensitive to both plug brand and gap setting. I strongly recommend avoiding NGK plugs in this motor (although I use them on other vehicles where they are an appropriate choice) and suggest using only Autolite # 63, ACDelco # R42CXLS, Champion Truck Plug # 4430, or Bosch # 4306 platinum +2, or Bosch Fusion # 4506.

    I hope this helps!!!
  • I recently changed plugs and wires on my daughters 2000 metro 4-cylinder. I was confused by how many wires needed changed. I told her to go buy plugs/wires, she came back with 4 plug wires but I only saw 2 that I could change. The other 2 just have wires (not plug wires) that connect to other plugs.
    One more thing, does the 2000 metro have a fuel filter and a mass air flow sensor?
  • "One more thing, does the 2000 metro have a fuel filter and a mass air flow sensor?"

    2000 CHEVROLET METRO 1.0L 3-cyl Engine Code [6]

    Fuel Filter WIX 33569 Fuel Filter
  • We have to replace cylinder head in 1990 Geo Metro because it had a crack and we bought a used cylinder head from another 1994 Geo metro in which there are 2 valves which are burnt.
    Here are my questions.

    1.Can we use the good valves from our old cracked head ?or we should buy all new valves?
    2.Replace only those 2 burned valves? or replace them all?
    3.What is the best way to check this new head and valves that it is going to last for some time?
  • cafanncafann Posts: 27
    My mother has a metro 4cyl with auto trans. been running great still does however a noise has come up and until I can confirm what it is she'd not driving it.

    The noise is like a metal rattling sound when the engine is running. It sounds over near the belts, so the pass side of the car. I listen sloser to the engine and it sounds within right near the belts.I noticed something sounded funny weeks ago but now the sound is much louder.

  • May be the crankshaft pulley. These models are known for this problem. There are other posts on this site describing it. I have a 96 Metro with the same problem. If it hasn't already, it will eventually cause the car to run rough because the wobbling pulley throws the crankshaft position sensor off. There is a post on this forum outlining a do-it-yourself fix. I haven't tried it yet, but plan on it in the spring.
  • hey folks, I am new here and I am looking to find some one who can tell me if the geo engine can be used as stationary power scorce. If so dose it matter what year.Would appreciate any help I can get. Thank you in advance.
  • I have a 1997 Geo Metro lsi with the 1.3L 4 cylinder engine. It starts and runs great. Has about 230,000 miles on it but after warming up and driving maybe about 30 miles it acts like it runs out of gas. I pump the gas a few times and it runs ok for a while longer or does it again after a few miles. The local repair shop can find nothing wrong but, did reproduce the problem. They put a fuel pressure gauge on it and ran it. The fuel pressure is good even when this happens. I have changed the fuel filter, spark plugs, wires, rotor, cap and even the coil. It also "seems" to be worse when driving in rain or fog, if that would make any difference.
    Today it totally quit on my. I coasted over to the side of the road, turned off the ignition and restarted it and drove the next 10 miles (about) to work without any problems (my total commute is 66 miles one way).
    Any ideas as to what to check???
  • While shopping online I see many different part numbers for shocks and struts for my 92 metro. I know the convertible has 13" wheels, so does that affect which front strut to buy. The KYB's have a different strut for left or right side but the other manufacturers don't. What's up with that? The monroes have three different struts for this year car, so which one is the right one?
  • geonewbiegeonewbie Posts: 2
    edited February 2010
    I got this car from a friend for nothing , he said he drove it home shut it off and it wouldnt start back up again. It cranks gets gas has good spark. what should I look for now ? Heck I got the car for Free I really cant go wrong , it doesn't look like it a very compacated engine.Thank you for your time reading this post. :)
  • zendenzenden Posts: 62
    Check for water in the gas, compression on all cyl's; fuel pressure; try to start it by spraying it with either. Check the spark is it blue; if not! test the the coil resistance. If compression is low it could be more then 1 burnt valve, or a combination of burnt valves and or blown head gasket; they are known for burnt valves. What engine do you have the 3 cyl? If compression is low on all cylinders first check the timing marks on cam and crank shaft.
  • It is a 3 cyl 1.0.
  • I have a 98 metro 1.0 5 speed 108,000 miles. Runs great but when cruising about 60 mph sometimes it stalls just like i had turned the key off, usually within 5 seconds it will kick back in and all is well for awhile. Usually fethering the pedal at cruising speed will produce this affect also. Sometimes it wont start also but waiting about 5 min it starts right up. I caan hear the fuel pump kick in when i turn the ignition so thats good. No smoke, no sign of head gasket problems, not sure what casuses it. Anyone have any ideas???
  • zendenzenden Posts: 62
    It sounds like a fuel pump regulator; they are regulated by the vacuum level; but they don't go bad very often; but it is possible. The regulator could do just what you described on an idle; when starting, or when feathering the gas pedal; because under these conditions the pressure regulator is to respond; you could do a fuel pressure test. Test the regulator for leak down pressure; It could also be a bad electrical connection, or a chafed wire,even tho you can hear the fuel pump run, it is an intermittent problem. I have seen this problem on the same type of car and found a chafed fuel pump wire under the back seat on the right side. The wire was hanging by a thread for 2 years and having the same intermittent problem all of that time. The fuel pump ran, but not good enough, believe it or not! I think that I have seen it all. Not to say that you have the same thing wrong. It is hard to diagnose on line, in fact it can often be very difficult when it is in front of us; so good luck hope this helps some what. I would like to here others input on this subject.Keep me up to date, I will help if I can.
  • This has been very confusing to me, and all the people at autozone tell me is that i need a injector. However at just a glance you can tell that fuel delivery is good. Started with a sputter every now and then on the highway, to dying at an idle. Changed plugs and fuel filter (both were nasty),and got it to running. now it just doesn't idle correctly, when turning the lights on it will die under the load. one thing to another. any ideas???
  • Thanks for the info! Where is the fuel pump regulator located? The fuel pump wire under the back seat, is it inside the cabin or under the care? Thanks alot.
  • zendenzenden Posts: 62
    edited March 2010
    If I where you I would have a fuel pressure test done first. But it would need to be done properly to diagnose the fuel supply system, including a leak down test to see if the pressure was holding after it is shut off; this would be the way to test the regulator properly. As far as a bad connection under the back seat! This would more of a long shot, and less probable cause of your troubles; But if you want to check that connection anyway; yes inside of the cabin it has 3 wires going to the pump, Black, yellow, and a purple one. you could check for bad connection where they connect together toward the passenger side.
    The regulator is under the air filter housing it is held in by 3 or 4 small screws holding it in; the screw heads are facing up at you; there are 2 rubber gasoline hoses connected to it (one thicker then the other) they run parallel to each other; the other end of these 2 hoses connect near the center of the fire wall. The thicker hose is your fuel supply from the pump and filter. The thinner of the 2 rubber hoses is your return line back to the tank. The purpose of the regulator is to relieve the un necessary pressure that is built up by the pump and return it back to the tank through that smaller of the 2 lines. Now that you got that! and I know what I am about to say will sound like allot of If's BUT!
    If you don't want to pay for a pressure test to be done and or do not have a friend to test it for you and If you could replicate the problem at will; and assuming that the problem is being caused by the regulator by releasing off to much pressure that is needed then! Replicate the problem and then by using a pare of Vice Grips squeeze the thinner return line as it comes out of the regulator, this will boost the pressure to the max by not letting it return, in turn the engine would smooth out and run right if the regulator was the cause. Even if you had to drive the car like this temporarily with it clamped to test it; it should hurt anything at all. I have fixed cars that the return lines where clogged up completely; the only symptom was they ate more gas and no one could figure out why.
    If the regulator is the problem, you can take the screws out; remove the diaphram ( inspect it for cracks or dry rot ) it is slightly loaded by a spring so watch out not to lose it! Spray cleaner down inside as needed look for maybe a grain of sand or something! Then put a small amount of grease on both sides of the diaphragm around the edges where it seals, and bolt it back together; Its cheeper then buying one!
    I hope this helps you.
  • i have a '95 geo metro automatic, 4 cylinder, 1.3 engine. i need parts. right now i need a rocker arm. does anyone out there have any suggestions about where to find any parts for it. are anyother car parts interchangable?

  • zendenzenden Posts: 62
    edited April 2010
    I like this link, They have alot of GEO parts, but they dont have your rocker arm:
  • blexodusblexodus Posts: 1
    We had the head rebuilt last year. This year we had the engine completely rebuilt because the front seal was leaking. Now when we travel on the freeway about 50 miles an hour white smoke comes out of the tailpipe. Looked inside the air filter and it was covered in oil which is going into the carburator causing it to burn oil. I do not know why oil is blowing into the air filter and into the carburator.

    Can anyone offer any help. Did not have this problem before it was rebuilt.
  • zaken1zaken1 Posts: 556
    edited April 2010
    Small correction here; Geo Metros do not have a carburetor; what apparently looks like a carburetor to you is actually the fuel injection throttle body. All Metros have throttle body fuel injection.

    When the air filter becomes clogged with oil; it will mess up the way the motor runs, particularly at high speeds. So you'll need to replace the air filter element, in addition to fixing the cause of the oil loss, before the engine can be expected to run right. The oil is coming into the air filter housing through the breather hose from the valve cover. One of the most likely causes of oil from the breather entering the air filter housing is a clogged PCV valve. The PCV valve is located just below the air cleaner, underneath the "T" in the breather hose which runs from the valve cover to the base of the air cleaner. Oil vapor from the engine normally flows out of the breather hose, down through the PCV valve, and through the intake manifold into the engine. But when the PCV valve becomes plugged; oil vapor then passes upward through the "T" in the breather hose, and goes directly into the air filter housing (where the first thing it does is to coat the air filter with oil).

    So I would replace the PCV valve, and make sure the air passage below the valve is not plugged. I would also replace the air filter element, and I suggest replacing the spark plugs as well; since they will often become fouled from running with a clogged air filter.

    If the motor is mechanically sound; the air filter should not plug up with oil again after the above items are replaced. But if the engine has been damaged by improper break in, by using the wrong grade of oil, by overheating, by using the wrong spark plug type, or by incorrect ignition timing adjustment; there will then be excessive quantities of oil coming out of the breather; and this will plug up the air filter even when the PCV valve is not clogged. In such a situation; your rebuilt motor will either have to be replaced; or rebuilt again and maintained properly this time.

    If you respond to this post; please include the year, model, transmission type, and number of cylinders your Metro has (assuming it is a Geo Metro). Also please include the length of time and number of miles on the rebuilt engine, the brand and weight of oil that has been used in that motor; and how many miles were on the rebuilt motor when the first oil change was done. I can suggest more specific options after I learn whether the motor has been damaged or not.
  • zaken1zaken1 Posts: 556
    edited April 2010
    You can buy parts like rocker arms for your Metro from a Chevrolet dealer. But if the reason you think your car needs rocker arms is because they are making clicking noises; it is probably not coming from bad rocker arms. Instead, clicking noises in the Metro's valve gear usually come from bad hydraulic valve lifters. Many small cars do not use hydraulic valve lifters; but the Metro does. These lifters are very sensitive to dirt in the oil, and will stick and make noise if the oil has not been changed often enough, or if low quality or non detergent oil has been used.

    Although Rock Auto does not carry Metro rocker arms; they do carry hydraulic valve lifters. The part number for the 1995 1.3 motor is Beck Arnley # 0227001. Price is $11.82 each. Intake and exhaust lifters are the same. This is a part which is very risky to buy used; because they are so vulnerable to dirt, and also because they wear in to match the mating parts on the engine in which they are used. If you put used lifters in a Metro; they will probably cause trouble.
  • Hi,

    Why, if the engine overheated, could there be oil in air filter box?
    What actually happens?
    Because I have a 91 Geo Metro/1.0L/A/T/133,000 miles and I did have this over heat on me and there is oil in air filter box!

    Thank you for any help!

  • zendenzenden Posts: 62
    Most likly blown head gasket or scored cyl. walls.
  • zaken1zaken1 Posts: 556
    edited April 2010
    There is a vent hose for the crankcase vapor; which runs from the valve cover to a "T" fitting that connects between the PCV valve and the air cleaner housing. Under normal conditions, most of the oil vapor is drawn into the engine through the PCV valve. But there is also a minor amount of vapor which goes into the air filter housing. A motor which is in good mechanical condition will not generate enough oil vapor to clog the air filter; but over time, there will still be a visible amount of oil left in the air filter housing. As the engine's pistons, rings and cylinder walls become more worn, the quantity of combustion gasses which get past the pistons and enter the crankcase will increase; and thus the amount of oil deposited in the air filter housing will increase. One measure of the engine's mechanical condition is how often the air filter housing (and throttle body bore) needs to be cleaned of oil deposits. I would say that if the oil deposits need to be cleaned out more often than about every 3 months; the engine is excessively worn.

    But, if the PCV valve becomes plugged or restricted; the vapor which normally goes through the PCV valve will instead go into the air filter housing. And that can make it appear that the motor is bad; when it is not. So I would always remove, clean, and test or replace the PCV valve, before assuming that the engine is producing excessive oil vapor. If too much oil is put into the crankcase; the same thing can happen.

    When an engine overheats; it can cause detonation (violent combustion) which can damage the pistons, rings, cylinder walls, valves, and/or head gasket. The heat can also cause distortion of the precisely machined cylinder bores and the head sealing surface. If any of these parts are permanently damaged; it will often lead to excessive "blow by" of combustion gasses past the pistons and into the crankcase. And the large quantity of oil vapor produced under such conditions will quickly flood the air filter housing and clog the air filter; even when the PCV valve is working correctly.

    This is why it requires judgment to decide whether the presence of oil in the air filter housing is a sign of a problem; or not.
  • we replaced the bottom half of the engine, had a hard time timing it and now it seems like it is running to rich, flooding itself, it is a geo metro lsi 1991, help!
  • zendenzenden Posts: 62
    edited May 2010
    Often when rebuilding, people forget the importance of reconnecting the ground wires to the engine; I am speaking of the small wires that connect the ECM to the eng; it bolts on to the rear of the plentum below the throtle body; it is connected with a 10 MM bolt. Or it sounds like the timming is retarded. You said that you had trouble setting the timming; I assume that you meant the distributor, and not the belt! Also maybe the spark plug wires are in the wrong place; each one maybe inserted into the cap to far to the counterclockwise position; If this is what is wrong then the eng. would run but have no power at all, the eng would lope and idle low. Move each one to the next hole in the clockwise direction. and turn the Distributor clockwise all the way, as far as it will go. If the eng wont start but kicks back or backfiers out the intake, turn the distributor in small increments counterclockwise to retard. If it backfires out the exaust then it is to far retarded. If it backfires no mater where you set the dist. after changing the wires then put the wires back where they where, and look for the reason for the trouble. a potato in the exost or cloged cat will do the same thing as you discribed.
    Let me know what you find. Hope that somthing that I said will help
  • rus6rus6 Posts: 1
    i have a chv metro 1998 1.3L that i am replacing the timing belt i have a repare book but it dos not show the timing marks on the cam shaft or the crank shaft when replacing the timing belt? HELP?
  • torakkitorakki Posts: 7
    I just rebuilt the engine on my 2000 Chevy Metro (valve job, pistons, rings, bearings) and when I finished putting it together and started it (started instantly). The idle is about at freeway speeds. Throttle butterfly is all the way closed. It runs smoother then ever, just way to fast. Before the rebuild, it idled fine, other then rough from a cracked and some burnt valves. One time, after letting rev for about 5 seconds, it started to slow then went slow and fast with a 1 or 2 second cycle. I've been turning it off after 4 or 5 seconds since I have brand new everything inside and wish to run it slow for a while. Any thoughts on what it could be? Air flow sensor on intake, crank sensor??
    Thanks in advance.....
  • zaken1zaken1 Posts: 556
    There is no air flow sensor on this motor. But if you did not connect all the idle air control valve hoses to the right places; there could be a massive vacuum leak into the intake manifold; which is what this sounds like to me. An EGR valve that stuck open or is being actuated at idle could also do this. Try disconnecting and plugging the vacuum hose to the EGR valve. If the throttle return spring has not been connected, this could do it, too. So could a PCV valve which was not in place, or a power brake booster vacuum hose which was left off.

    If the distributor was timed too far advanced, this could also do it. And if someone had broken the seal on the throttle stop screw and used it to speed up the idle when the valves were bad, that screw will now have to be turned back to the correct position (which is about 1/4 turn open from a completely closed throttle butterfly.)
  • torakkitorakki Posts: 7
    Thank you for the response. You hit it on the head. After checking all the vacum lines and hose connections, I couldn't find it but was sure it was a vacum leak. Then I saw one of the fuel injector wasn't seated right and air could get past it into the head. Loosened the fuel rail, repositioned all the injectors, re tighten the rail and, went to start it. It runs fantastic!!
    Thanks again for your help......
  • zendenzenden Posts: 62
    The crankshaft woodruff key will be at 12:00 ; this will make the lower marks line up.
    The camshaft has a pin sticking out, it will be at 6:00; then put the cam sprocket on, it has two slots coming out from the center hole; when correct the slots will be pointing toward 1:00 and 6:00 - ( NOT at 6:00 and 11:00) . Now the upper sprockets timing mark will line up and the lower mark will line up; both will point upwards. This is all you will need to know if you do it as I wrote. This info is correct for a 98 GEO Metro 1.3
  • trmechantrmechan Posts: 5
    I recently picked up a metro with the head off for a blown head gasket. I had the head checked and repaired and I installed it. Now the only way I can get the car started is to remove the bolts from the dist. and advance the ign. timming beyond the slots in the dist. I know I have the cam timming correct.
  • zendenzenden Posts: 62
    On the distributer try moving each sparkplug wire to the next whole in the counterclockwise direction, then set the timming.
  • danieldltdanieldlt Posts: 2
    I rebuilt this 1.3 L Piston rings, Crank bearings Rob bearings, Honed cylinders, Head worked on by separate shop valve job new seals and guides. Originally 97K but exhaust was smoking blue and compression was down to avg. 120 psi so decided to rebuild. After rebuild engine acts like it wants to start first 4 or 5 revolutions then stops. Plugs continue to be fouled by oil and fuel, cleaned them over and over. Timing should be on, have fuel pressure and fire from plugs... Any help you can think of would be greatly appreciated. Please help. Thanks!!
  • zendenzenden Posts: 62
    edited May 2010
    Are you sure timming is correct first? The cam sprocket has 2 timming marksthat are 180 degrese apart. the correct way is!
    The crankshaft woodruff key will be at 12:00 ; this will make the lower marks line up.
    The camshaft has a pin sticking out, it will be at 6:00; then put the cam sprocket on, it has two slots coming out from the center hole; when correct the slots will be pointing toward 1:00 and 6:00 - ( NOT at 6:00 and 11:00) . Now the upper sprockets timing mark will line up and the lower mark will line up; both will point upwards.
  • danieldltdanieldlt Posts: 2
    zenden, Thank you very much for the correct alignment position on the cam gear. I did have it wrong and have corrected it as per your information. I dont know why but injectors 1 & 2 are net getting the go ahead from the ECM/ECU, 3 & 4 seem to be working fine. Checked the blades on the cam that pass by the Cam position sensor and the look identical, could the cam position sensor be bad? How would I check it and , when I have the sensor unplugged 1 & 2 seem to be spraying intermittently??? I don't know what to do. Fixed the timing issue and now have another setback... Thank you for your time.
  • zendenzenden Posts: 62
    Sounds like a common mistake; maybe you forgot to ground the ECM back to the eng? Make sure the ground wire coming out of the main harness is bolted back on to the engine! On that eng I am not sure where it is located, On the 3 cylinder it would be locater on the firewall side of the throttle body (down low) it is bolted to it with a 10 mm bolt; on the 1.3 I am not sure! Hope this helps!
  • 3door3door Posts: 2
    Car is hatchback with 5spd manual and air, had it since new, now has 95,000 miles. In 2008 had it to repair shop for fast idle, 25mph. Blown ptc fuse caused by shorted EFE. EFE left unplugged. Still had a problem with fast idle, now up to 55mph in 5th gear without pressing on gas pedal. Computer replaced and ground wire added. Weather cooled down an Metro ran OK. Warm weather in 2009 above 60 degrees and car acted up, let it sit all summer. Drove it during winter (cooler months) no problem. Warm weather 2010, car is acting up again. Car may idle normal when started but once the engine starts racing it stays that way till the next morning, when it starts OK. It does still run at least 55MPH when the problem starts without touching the gas pedal. Thank goodness for a manual. Any ideas..
  • zaken1zaken1 Posts: 556
    edited May 2010
    Here are several possibilities, listed in descending order of likelihood:

    1> Try replacing the intake air charge temperature sensor (located in the air cleaner housing). And be sure that there is no aftermarket "performance chip" that has been connected to the IAT sensor wiring.

    2> Try replacing your coolant temperature sensor. The sensor on your car has two sections; one section drives the temperature gauge, and the other section tells the computer when the motor is warmed up. If the section that talks to the computer was defective, it would make the computer think the engine was always cold; which would create an excessively rich fuel mixture when the motor was warm. That could substantially raise the idle speed.

    3> Locate the idle air control valve (mounted on the driver's side of the air cleaner close to the firewall and the throttle body). There is a vacuum hose between the IAC valve and the intake manifold, below the throttle body. Make sure that all the vacuum hoses are securely connected and there are no cracks, tears, holes or any type of leaks. Check the vacuum hose from the brake booster to the intake manifold, and the hose from the back of the throttle body to the MAP sensor for similar leaks.

    4> There is a relay on that car called the throttle control relay (also sometimes called the idle speed control relay). Try replacing that item.

    5> There is a part called the throttle position sensor, which is mounted on the passenger side of the throttle body. This sensor is mounted with two bolts, which pass through elongated slots; so the sensor position can be adjusted after the mounting bolts are slightly loosened. Carefully note the position of the sensor mounting bolts in their slots, and then loosen the bolts just enough to allow the sensor to be turned by hand pressure. Turn the sensor counterclockwise a small amount, and retighten the mounting bolts. Try driving the car after making that change, and see whether the idle speed is reduced. This is a very sensitive adjustment: It may be necessary to repeat this procedure several times; before you reach the optimal adjustment point. If you turn the sensor too far counterclockwise; the motor will begin to hesitate or falter when throttle is applied.

    6> Make sure the throttle cable is adjusted to have enough play to allow the throttle to close completely when the motor is warm. You should be able to grasp the pulley for the throttle cable on the driver's side, and be able to turn it clockwise until you can feel the linkage hit the stop screw. If the cable is adjusted too tight; you'll feel the cable become tight and prevent the pulley from turning before the linkage hits the stop screw. Sometimes someone breaks the factory seal, loosens the lock nut on the stop screw, and incorrectly adjusts the stop screw so that it does not let the throttle close fully. In that situation; the throttle stop screw must be readjusted to allow the throttle to close further. THIS IS AN EXTREMELY SENSITIVE ADJUSTMENT.
  • raywisraywis Posts: 1
    Friend's towed metro will start one morning & then will not for a couple of days? cranks but not run. fuel pump,& filter have been replaced. Also distributor cap & rotor all by a certified Mech. didn't correct the problem. Any ideas?
    [email protected]
  • zendenzenden Posts: 62
    This could be many things wrong. Basically you should diagnose first with the symptoms; as in do you see a pattern? Could it be a lot of moisture in the air where you live? GEO 3 cyl’s can have troubles with that; unique to a 3 cyl especially if one of the cyls are week to start with; If you suspect a moisture problem it is usually an air gap where the spark plug boot plugs in to the sparkplug. The rubber boot must seal the sparkplug hole going into the head or condensation builds up around the sparkplugs.
    If moisture is not the trouble then when it will not start check for spark and fuel, it takes both of them to fire up. The coil should throw a half inch spark while cranking. The fuel pump should run for about 5 seconds as soon as you turn the key on. Some times people replace fule pumps when the relay was bad, or a bad connection some ware. There are ignition relays and fuel pump relays in cars. Ignition switches go bad at times; coils go bad and many more. So find out if it is a lack of fuel or ignition spark, because if you have enough of each of them, then it opens up a box or many more questions related to timing, compression, ect.
  • 3door3door Posts: 2
    zaken1 Thank you for the information, I'll let you know how I make out.
  • heavyhookheavyhook Posts: 12
    I was cruising down a local Hwy at 60 mph in my metro with 81K miles when she just quit. I popped the hood to try and find out what hat happened. The main 60 amp fuse had been blown. I checked the battery hot wire to the fuse panel, starter and alternator for a short or chafing. Nothing found. I took the top off the blown fuse and inserted a dime to jump across the fuse. No sparks, no wires , nothing seamed to be getting hot or warm. Tried to restart, cranks good but wont start, took the distributor cap off and had friend crank motor over. Rotor spins fine. so timing belt is not broken. I had replaced it at 55K. Re installed cap and pulled spark plug wire off # 1 cyl. cranked motor over again but no spark. Checked for power and have hot wire up to coil. I havent checked resistance on coil. Not really sure of procedure for checking coil. Rotor and cap contacts are clean. No points looks like electronic ign. Any Ideas would help, Thanks
  • zaken1zaken1 Posts: 556
    edited June 2010
    This is an unusual situation! The most likely cause of the fuse blowing would be that a diode in the alternator shorted out. The diode or its circuit wiring could have then gone open before the fuse blew. That would now leave no sign of a short.

    How did you test for spark at the plug wire? The wire terminal is recessed far enough in the plug boot that it probably wouldn't be possible to see a spark unless you had inserted a bolt or spark plug into the wire, and then held the plug so that the threads were pressed against a grounded object, or held the bolt head about 1/4" from ground. If the sun was shining, it would make it even more difficult to see a spark. A more reliable way to test for spark would be to disconnect the distributor end of the coil wire from the distributor cap, and hold the wire so that the metal end (which projects out beyond the boot) is 1/4" from ground while the motor is being cranked.

    If you really don't have a spark; try disconnecting the heavy power wire from the alternator; and then check for a spark from the coil wire again. It might be that there is a partial short remaining in the alternator, which is shunting power away from the ignition system.

    I would not bother trying to check the coil resistance; it is highly unlikely that it would short out completely enough to blow a fuse. Besides; the fact that you have battery voltage at the high side of the coil proves the coil is not shorted out. If it was shorted, there would now be little or no voltage at the coil high side (as that point would now effectively be grounded).

    It sounds more likely to me that whatever blew the fuse is also now keeping the motor from running. This could be a short in either the fuel pump, fuel injection, ECM, or ignition circuit. There are relays which control most of those circuits. If a relay went bad, it would shut the motor down; and might also have blown the fuse. The fuse block that contained the 60 amp fuse also contains the fuel pump relay and several other relays. Many of them are physically interchangeable.

    So I would try turning the key on and listening for the sound of the electric fuel pump. The fuel pump normally will run for about 5-10 seconds after the key is first turned to the position where the dashboard warning lights come on. If it is noisy where the car is located, you might need to have someone stand next to the rear wheel on the driver's side so they can hear the pump better. Holding your head out the open driver's window may also make it possible to hear the fuel pump; but don't do this with the driver's door open; as that will cause the door warning buzzer to sound.

    If you do not hear the fuel pump when the key is first turned on; then try exchanging the relays that are mounted outside the fuse block, on the front side. You can also do this with any relays inside the fuse block that are the same size. It would also be important to check all the fuses in the fuse panel under the dashboard, on the driver's side.

    If you post your experiences with trying to get a spark and the fuel pump to run, I'll keep an eye on this site; inn order to give you additional suggestions based on your feedback.
  • heavyhookheavyhook Posts: 12
    With reguards to checking for spark. While broken down on the side of the Hwy, I used a new alligator clip that is about 2 inch long and on one end is a 3/16" round end you can use to crimp on the end of a wire. I inserted that end into the end of the #1 plug wire. I held it 1/8" off the metal housing of the distributor while having a passenger crank the motor over. NO SPARK ! I have worked on and continue working on muscle cars for the past 35 years. I am far from a novice. When the engine quit running I checked the fuses under the hood first. I had zero electrical power inside the vehicle to 100% of the systems. I grabbed my 12 volt test light from the tool bag I move to every car I drive. The Metro had been drove once it the last 16 months. I am relocating about 100 miles my from current home. I changed the oil and filter, checked all the fluids and checked the air in all the tires. Shoot, I even gave it a bath! I borrowed the Optima battery out of my 71 Mach 1. I made the 100 mile trip with a/c blowing cold air all the way. About a 2-1/2 hour drive without a problem one.. I parked the metro in my new garage, removed the battery to return to my Mustang. While on a return trip moving things to my new home, My 2004 F-250 Diesel had a cam sensor go bad. Since my new home is out in the country in North Central Texas, I had to order the part from a O'reilly's auto parts store which is about 15 miles from my new home.. The next day I borrowed a Optima Battery from my F-250 truck to run to the retrieve the cam sensor. My little car fired right up as usual. I made it about 3 miles from my house when the Metro died all at once, not a hint of a impending problem.
    My father bought this car new in 93. I purchased it from him in 03 with 61K on the speedometer. The only mechanical problem I have ever had is replacing the clutch about 2 years ago and the alternator about 6 months later. I have only put about 1,000 miles on the Metro since then. I did have a problem with the first replacement alternator I purchased. With just the slightest amount of tension on the alternator drive belt the bearing in the front side of the case would cause it to lock up. I had the before mentioned parts store order another alternator. The one thats on the car now is that replacement. While installing the alternator I encountered a similar problem only not as bad, I could tension the belt by just pulling on the alternator case by hand and tighten it down there. Any more tension would lock the front bearing down as before but it was enough to keep the belt from slipping. All seemed to be going good until the latest installed alternator had about 500 miles on it. Then the front bearing started squealing for just a couple of seconds after the engine was started then would quit and seamed fine..
    I can see that if a diode shorted out where it could blow the 60 AMP fuse. If it were the fuel pump or ECM ect. I would think It should have blown a smaller fuse that protects that specific circuit. As I mentioned in my first post. To blow the 60 Amp main fuse, seems it needs to be a very serious, high amp draw short in the alternator or starter motor. I checked the main hot leads from both back to the fuse panel and battery for chaffing but found none. As I mentioned before while broke down on the side of the road I used what I had, a dime in the top of the fuse where the bimetal bridge burnt out. There was no sign of a short still existing when I jumped across the blown fuse. All systems seemed to have full power. I had my flashers on for a good 45 minutes after jumping across the blown fuse. The emergency flasher lights were bright and working correctly. All the way back to my new home as I was being towed. My test light was burning bright when I checked the hot wire to the coil.
    It will be another week before I can get back down to where the Metro is to do anything else. I am not sure how your suggestion of unplugging the coil wire from the distributor is supposed to work . If you try to short directly from the coil to distributor feed there is no way for the current to build up inside the coil to jump a gap. Anyone cranking the motor over would have no effect on generating voltage to test for a spark if the current is not being run thru a distributor giving the coil time to recover between each plug firing cycle.
    Well thats about all the history I can provide. Ya know, 35 years ago when everything had points and mechanical fuel pumps It was an ART to fix a ignition or fuel system problem and there was a 90% chance that with a few tools and a few years experence you could get the old car fired back up and get home on your own. Now its 90% science, You take what ever gizmo you suspect to a parts store where some young man, who has only being supporting his self for 3 or 4 years will do there best to sell you every sub-component in the system you suspect of being at fault. And this is what we call progress!!! Thanks for your input Doug Walker / Whitney,TX
  • zaken1zaken1 Posts: 556

    Thanks for the feedback. I'll try to clarify some of the points you brought up here. It sounds like we may be miscommunicating about the coil wires used to test for spark. Of course the primary (12 volt) feed must be connected between the coil and the electronics in the distributor (which take the place of the good old points and condenser) in order for dwell current to charge and discharge the coil. But I wasn't asking you to make any changes in the primary circuit. What I suggested was for you to disconnect the distributor cap end of the 7mm diameter high voltage wire that goes from the coil tower to the socket in the center of the distributor cap, and hold the distributor end of THAT wire close to ground. This wire is totally independent of the little primary wires that feed 12 volts to the coil to charge it. So the coil will still produce sparks during this test; just like it does when you disconnect one of the 7mm plug wires from a plug and hold it close to ground. The high voltage current from the coil does not need to pass through the distributor cap or rotor in order for the coil to be recharged. It is only the primary circuit's little, 12 volt colored wires and the low voltage electronics in the distributor (that substitute for the points and condenser), which are needed to charge the coil. If the primary circuit works; the coil will produce sparks; regardless of whether they go through the distributor cap or not. (If that was not true; the new cars that have an individual coil on each spark plug and no distributor would not be able to work; as their plug wire goes directly from the coil to the spark plug). It is important to understand that once the coil is charged by the primary current; it will jump a spark anywhere it is strong enough to go; regardless of whether it is a large or small gap. The spark has already been generated inside the coil; it does not depend on the size or routing of the gap in order for it to fire or to recharge. Please trust me on this; I have made a living as an auto electrical specialist for over 40 years, I also taught courses in engine theory at MMI in Orlando, FL, and I have been developing and refining my own electronic ignition circuit since about 1970. I also have owned a 1990 Geo Metro 1.0 since 1992. And I have answered over 1,900 questions on the Edmunds Answers forum in the last 18 months (where I am now ranked # 3 in the last 30 days). Sorry if that sounds like boasting; but my students repeatedly told me that electronics was the most difficult part of the course for them to understand; and I often had to correct misconceptions they had about electronics before they could gain a clear sense of what was going on.

    The reason I wanted you to check for spark at the coil wire instead of the plug wire is that the distributor cap and rotor can sometimes ground out from a high voltage arc breaking down their insulation. If you bypass the cap and rotor; there is that much less chance of a defective external part messing up the test. Also; the timing belt can sometimes slip and still turn slowly; or even stop turning after you put the distributor cap back on. There are several other spark tests which can be made with the cap off; which may prove valuable in sorting out what is going on here.

    You are correct in concluding that it must have been a high current arc which blew the fuse; and that most components would have lost smaller individual fuses if they had failed. Incidentally; the starter is not fused; since it normally draws as much as 100-150 amps, so it could not have been the item which blew the fuse. This pretty much leaves the alternator as the prime suspect. FYI, over the years, I have gotten so many defective rebuilds from O'Reilly that I absolutely refuse to buy any more rebuilt components from them. They apparently have the work done in Mexico by people who are told to not replace anything they don't have to. It is criminal to not replace bearings in alternators; no matter how good they may look. So, in order to remove one more unknown factor from this process, I request that you please disconnect both the power cable and the smaller plug from the alternator, and wrap or tape them up while doing the rest of the testing. If there is a NAPA store in your area; that is a much more reliable place to get rebuilt parts.

    Regarding the distinction between auto repairs being an art or scence; 35 years ago, I would have become a rich man if I had a dollar for every carburetor that someone wrongfully condemned because they weren't able to figure out the difference between a fuel system and an ignition problem. About 90% of the car problems people would bring in to my shop were ones they believed to be fuel system problems; but when I tested and repaired the car; 90% of the problems which the people had reported actually turned out to be ignition problems. And about 90% of the carburetors I adjusted were previously set too rich; because excess richness is a great band aid for covering up improper ignition adjustments. So science was just as important to know in those days as it is today. But I will agree that the old low compression, mildly cammed motors are far more forgiving about tuning errors than todays precisely calibrated, low emission, fuel efficient motors.
  • trmechantrmechan Posts: 5
    Tried moving plugwires. Could not turn dist. far enough to get stated.
    Had to move timing belt off one notch on cam gear to get unit started and timing
    set. Engine still runs rough.
    Need to find out how to set tp sensor on 95 GEO with upgraded emissions.
    Sensor only has 3 wires in the plug. MOtor manual says to use a Tech 1
    scantool and I don't have one.
    I may also have another problem upon inspection of the intake I found the locknut
    on the throttle is loose. I don't know if it has been messed with.
    Please help.
  • zendenzenden Posts: 62
    You need no TECH 1 to set the TPS
    With Key On Use .14 inch or 3.5 mm feeler gage between throttle stop screw and throttle lever;
    If the idle speed control motor plunger is making contact with throttle lever screw, then you must bring Eng. up to normal operating temp so that it will not touch it. Then back probe the TPS with the feeler gage in place. The TPS has 3 wires, using a DC volt meter on low scale puncture the middle wire with your probe; hold it there and probe the outer 2 one at a time until you get your reading. TPS should read between .98 and 1.02 DC volts, if not adjust or replace it. A good TPS will smoothly increase in volts as you increase the throttle. let me know how it goes
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