Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Geo Metro Engine Questions



  • depattdepatt Posts: 6
    Problems that come and go with no logical pattern are often electrical connections. I had a bad connection to my fuel pump under the rear seat. Intermittently it would cause the engine to barely run, spit and sputter. After the car cooled off, everything was fine again.The connector was fine most of the time, but when it got hot a poor connection was only making good enough connection to keep the engine barely running. I pushed the connector together tighter and all my problems went away. If I had mounted a fuel pressure gage where I could see it while driving, I'm sure I would have seen the fuel pressure drop low when the problem occurred.
  • depattdepatt Posts: 6
    I think I found the problem. The connections to the fuel pump under the back seat was loose. The problem would go and come with no logical pattern. I've got 150 miles gone by with no problems. Thanks for the help guys, Nobody hit the problem on the head, but you gave me enough courage to keep looking.
  • jmar6jmar6 Posts: 3
    edited November 2010
    I recently purchased a 91 metro 3cyl 5speed no a/c. I guess it ran ok. I did the usuall tune up plug,wires, cap, rotor,fuel and air filter. It ran a little better. So I started to dig into it further,o2, cts, tps and found 2 things kind of odd. I cannot find the EGR valve and the voltage to the tps is just under 5.....0 at idle...then just under 5 off idle. Voltage should sweep gradually from about 0.5v to 5v, right? To me that sounded like too much. So I replaced the tps. Installed acording to the chiltons spec. Still the same. Just like the old one. I am estimating that my milage will be around 20mpg. Power does not seem to be lacking, a little boggy at take off then runs fine. Just crap milage! Currently 140mi with a quarter tank left. Any help?
  • zaken1zaken1 Posts: 556
    The TPS is different on manual transmission cars than on automatic transmission cars. The linear response you expect is only found on the automatic transmission vehicle's TPS. Manual transmission TPSs switch suddenly just off idle; exactly like yours does. There is a second switching point at about 7/8 throttle, which richens the mixture.

    The EGR valve is normally mounted on the rear of the intake manifold runner for # 3 cylinder; close to the throttle body. Here's a link to a photo: ( If there is no valve there; but you can see a block off plate on the manifold; then someone has removed the valve. If there is no block off plate on the manifold; then the engine you have was originally intended for a non-US application; or else is a mixture of US and non US spec parts. Such a motor will never run properly; because there is no computer that is calibrated for use without an EGR valve.

    Whether or not you locate or install an EGR valve, I would strongly recommend running a compression test on all cylinders. The normal compression pressure on this motor is 195psi. The minimum allowable pressure in any cylinder is 165 psi. If any cylinder pressure is below the minimum limit; the motor will not be capable of producing good fuel economy, regardless of adjustments.

    Other things which make this motor impossible to tune properly are the use of an unsuitable spark plug. NGKs just do not run well in Metros. The only plugs that run well in these motors are Champion # 322 (RN11YC4), Bosch Super Plus # 7907, Bosch Platinum # 4219, Autolite # 63 or # AP63, or AC Delco Rapidfire # 4. The plug gap should be checked before installation and adjusted to .041" if necessary.

    If the compression is within the above specs; and the recommended plugs are being used; disconnect both vacuum advance diaphragms on the distributor, plug the hoses, and check the ignition timing with a strobe light at idle. It should be set to 6 degrees BTDC at <850 RPM idle speed. Check both vacuum advance units to make sure they do not leak or bleed down when a vacuum is applied. Check the centrifugal advance mechanism by turning the rotor counterclockwise by hand to make sure it moves through the entire range of travel without binding; and springs back to the retarded position when it is released.

    If all the above items are correct, and the mileage is still that poor; the fuel injector is probably leaking at the seals. Rock Auto has an exchange process for reconditioning Metro injectors.
  • jmar6jmar6 Posts: 3
    I will check compression in the next couple of days. And will look for a block offplate for EGR. I know what one looks like and it is not there. I did put NGK plugs in, will change back to the bosch that I took out, they did not look bad. The car also has new exhaust from manifold, cat, muffler. I will keep you posted.
  • jmar6jmar6 Posts: 3
    Checked the compression today and holy sh_t!!! My guage must be wrong...100 on all three. I do not belive that for a second... I am used to driving with hp under my foot and this 1600lb, 3cyl, 5sp has enough hp to cruise @ 70 with little pedal and then some. There is no block off for the EGR. It just does not have one.still @ 22mpg is better than my 460 gets so I guess I can not [non-permissible content removed]. Run it until it blows, then run it over with my truck with the 460. All the componets test out whith-in spec, but it still idle hunts....anymore input?
  • depattdepatt Posts: 6
    edited November 2010
    I have a possible solution. Good news is it's free and easy to try.

    I had a similar problem that drove me nuts. After driving 10-20 miles without a problem I would suddenly lose power and was barely able to keep it going. Drop the car in neutral and it reved up fine. Put it in drive and it would spit-sputter, and barely run. It felt like I was running out of gas, when I knew the tank was full. Under the back seat (inside the car) there is a connector that goes to the fuel pump. A bad connection here is like shutting on and off the fuel pump (or down the road maybe just low fuel pressure as it makes and breaks) After the connection cools down and makes a good connection again the car is miraculously cured til you hit a bump or the connector heats up again.

    Connecting a fuel pressure gauge in line and taping it to the window where you can see it will pinpoint or eliminate fuel pressure problems. But for the connector, just clean or replace it and make sure you have a solid connection.

    BTW...low gas pressure may not produce any computer code.
  • If you connect a fuel gauge in line and tape it to the windshield so you can watch it as you drive, you can pinpoint or eliminate fuel supply problems. I had a bad connection to the fuel pump under the back seat that drove me nuts. The problem would go an come with no rime or reason. Felt like I was running out of gas with a full tank. Drop it into neutral and the motor reved up fine. Back into drive and it would spit and sputter and barely run.
  • trocatroca Posts: 3
    Owned '98 1.0 5 spd car for 8 years, 130K, problem just started. Will start and run normal when cold for about 5 minutes, then dies, no fuel from injector. After cold start all functions are normal. Have checked out TPS-engine wouldn't run for first 5 minutes throughout range if it was bad, movement looks normal on analyzer, injector measures about .8 ohms, resistor about 2.2 ohms, fuel pressure goes to 21-22 psi with igition, holds, pressure is constant at about 20psi at idle and running and maintains as engine dies. Once it dies, won't restart, no fuel from injector, gauge still will show good fuel pressure with ignition. Good spark at all times. If let alone to totally cool off, will repeat cycle again with perfect start and run for first 5 minutes. Any ideas?
  • zendenzenden Posts: 62
    when no start; Check for injector pulse with a noid light, You can get a free rental of one at Autozone
  • trocatroca Posts: 3
    Thanks for the reply, Zenden. I'll check for injector pulse tonight, also other basics loose wire, grounds, relays, etc. If no signal to injector when engine dies suspect ECU? No codes showed at any time through this "cycle" as we were hooked up to the OBD port and watching the whole time.
  • zendenzenden Posts: 62
    I assume that your car has no AC unit that helps control the idle? if so; I would test injector with a noid light first. If the injector signal is fine. It could be EGR sticking open after it worms up: that is if that car has an EGR; or the Idle Control Air Valve ( IAC ) As the eng warms up it is suppose to idle down the eng. If it closing to far it will stall out; take it out and clean the hole out where the pintle seats also clean the pintle. Do not turn the key on when the IAC valve is unbolted and plugged in. It will over extend and come apart; and good luck trying to put it back together again. Sounds like EGR or IAC to me! When the eng. is running good, ( in this order )shut it off then unplug the IAC Valve, then restart eng; see if that fixes the problem, if so clean or replace the IAC
    NOTE: If this car has an air conditioning unit the defroster runs off of AC unit and will affect IAC Valve
  • trocatroca Posts: 3
    Well, in usual fashion I went through more of the basics last night and after swapping relays, checking and cleaning the wiring connections under the rear seat, cleaning and checking the ground connections the car started and ran fine at idle for 45 minutes, never died so I never got to check the injector (although if it's running, the inj is working). Now thoroughly warm I took the car out and it ran great. Came back, had something to eat and then took all the test equip off and put it back together and went out and drove it hard for an hour and absolutely no problem. I am getting a better picture, however, as when this problem first surfaced, I had started the car and driven off with no warm up, as I usually do. Even after it seemed fine i noticed what seemed to be a stumble in that short off cold idle but not yet fully warm area and that may be where the problem lies. Normally I'd get much more into the details of this but the car will be scrapped in spring because of rust in the subframe even though it runs great. I'm just looking for 4 months out of it and it appears that if I let it warm up (gauge at normal warm position, takes maybe 7-8 minutes), all is well. Drove it to work, 25 miles freeway, today no issues. EGR moves easily (but don't know if it is actually sealing) and have thought about IAC. No A/C on this car. So for now, I'm learning how to make things work and may look at a few more components as I have time. Thanks for the input.
  • zendenzenden Posts: 62
    Sounds like you fixed it. On my GEO I had a bad wire connection under the back seat one time also; it was doing the same thing as yours. All cars need gas and spark to run. When turning the ignition switch to the on position, cars with electric fuel pumps will activate pump for the first initial 2 to 5 seconds then shut off automatically. When first diagnosing you can hear the pump run thru the tank fill whole, or under the car with your ear to the tank.
    By the way I have a manual trans. in my stock 94 GEO Metro LSI 1.0L, I never average less then 63 MPG at a steady 59MPH on a flat road with regular gas. Avg city is 47. You may not want to junk your car in the spring time because of rust. If it is the frame that is rusting near where the left front control arm bolts on you could sand blast and weld a patch to it before it brakes.
  • i have a 1991 geo metro, we have put a 1996 motor in the car, but we ended up putting the distributor from the 1991, but there is no vacuum hoses and there is no place on the intake for vacuum, what do we do? help!!
  • I have a 94 Metro and it will not start. Its on the verge of starting. It looks like the Crank Shaft sprocket is bad, but I was told by the dealer that they never go bad and that it is another problem connected to the crank. Do you have any ideas?
  • zaken1zaken1 Posts: 556
    Starting problems come from either low compression (which will happen suddenly if the timing belt slips or breaks), or from lack of fuel or too much fuel being injected into the motor, or from weak ignition.

    The professional way to sort out these possibilities is to first buy or borrow a compression gauge, or pay someone to check the compression in all cylinders. On the Metro; it should be at least 160 psi (normal compression is 195 psi). If any cylinder pressure is below that figure; the motor will not start or run reliably. Low compression in all cylinders often indicates the timing belt has slipped out of position.

    If the compression is good, look at the spark plugs. The electrodes which project into the motor should be clean and dry. If they are wet or the porcelain insulators are black; the plug will not be able to ignite the incoming fuel. The electrode gap should be .040" (1.0 mm). If the gap is significantly larger than that; the motor will be liable to not start. Install a new set of spark plugs if there is any doubt about their condition. I recommend Autolite # 63 plugs (use #5503 on motors with 5/8" hex plugs).

    Distributor caps and rotors will keep the motor from starting if they become too dirty on either the inside or outside surface. Spark plug cables must have less than 1,000 ohms resistance per inch of length. The battery voltage should not drop below 10 volts while the starter is cranking (if you don't have access to a meter; turn the headlights on, and watch the lights while trying to start the motor). If the lights dim substantially or go out when you run the starter, the battery is too weak to start the motor effectively. This can come from an old or worn out battery; or from an alternator that is not properly charging the battery when the motor runs.

    If there seems to be no problem with the compression or ignition; remove the air cleaner lid, and spray a two second burst of engine starting fluid into the throttle body air inlet while the throttle butterfly is held partly open. Then release the accelerator, quickly put the lid back on the air filter housing, and try to start the motor. It it starts and then stalls; the engine is not getting enough fuel. This may be caused by a clogged fuel filter, by the car being out of gas; or by a bad fuel pump or fuel pump relay.
  • NEVER SPRAY A 2 SECOND SHOT OF STARTING FLUID(EITHER) INTO A MOTOR! You will bend the piston rods if it fires. You should never use more than 1/2 second shots at a time while some one else is cranking the engine over. If the car does not start begine by trouble shooting the ignition system first. What gives you the impression the crank sproket is bad?
  • zendenzenden Posts: 62
    edited February 2011
    These pullys dont where out, but they do crack when over tightening the lower belt pully bolts also they will become damaged by the front crank shaft bolt being to loose. Many times the front crankshaft bolt will fall out or brake off when driving these cars, in turn the Wood drift key will brake and you will jump timing. You can tell this by: When turning over the eng. watch for the lower pully to wobble. Any wobble or lose crank bolt is a sign; and will most likly be the reason for the keway to have become broken. In this case you will need a new wood drift key and a new or used lower timing pully. NOTE: When testing timing; Never turn any engine counter clockwise; it will jump timing, In fact at times when an eng backfires it can easly jump timming.
  • I have a 3cyl 5 speed that has stalled out and I can't get it to start. new fuel pump, distributor rotor and cap, plugs. my compression is now at 90/60/60, obviously too low. the timing belt is new, and is set on normal specs, but I'm using a deltacam economy camshaft grind... not sure what adjustment I may need to make here... any ideas?
  • zaken1zaken1 Posts: 556
    This engine can never run with compression that low. Normal compression is 195, and minimum allowable compression is 160. If it has been running up until now and nothing else has been changed except the timing belt; then either the rings and/or valves have become worn to the point that they don't seal adequately anymore. Or, if it ran well before you changed the timing belt, and the engine is not excessively worn; this means the timing belt was not set properly (even though you believe it is). If that cam is a regrind; it may have been ground on a different centerline than the stock cam. In that case; you'll have to determine the proper cam indexing by splitting the valve overlap.

    The way to split the overlap is to remove the valve cover, and turn the crankshaft until the nose of both lobes for #1 cylinder are pointing upward. Then, using a caliper or a dial indicator; carefully rotate the crankshaft small amounts in either direction until both the intake and exhaust valve for #1 cylinder are opened an equal distance. You may need to reference the amount the valves are open against a fixed object; or lay a straightedge across the flange on top of the head and measure from that. Once you have determined the crankshaft position where both valves are open equally; look at the timing notch on the pulley, and read the mark on the timing cover degree scale that the pulley notch lines up with. That is the mark which should be used for setting the crankshaft position where the marks on the cam sprocket line up with the flange on the top of the head. The timing belt should be installed in that position. If the mark is way off the stock position (which I expect it will be) please check to see whether the woodruff key that locates the crank pulley on the crankshaft has been left out or sheared off. If that key was overlooked or improperly aligned when the pulley was installed; it would throw the marks way off and make it impossible to set the cam timing.
  • thanks for the breakdown...

    if the car was running though, and drove a bit (not a ton) on the new cam as is, would that have happened if it was that far off? Just seems like I would have never had it running in the first place if that was the issue.
  • race003race003 Posts: 2
    I have a 99 geo metro that came to me barely running.It started once when I had to move it. It was hard to start, had no throttle response until it warmed up.The next time I got in it it wouldnt start. I pushed it in the shop replaced plugs wires timing belt.It cranked but was hard to start , never would accelerate. 180,000 on the car never had any work done to it.My next step I replaced the fuel pump.After to replacing the fuel pump I lost spark no fire except as the key is released from the crank position.The crank sensor was oil soaked from the seal on the crank I replaced the seal when I replaced the timing belt and replaced the crank sensor. I have voltage to the coils with the key on and a good ground no spark.I have yet to locate the ingition module,where is it hidden on this car?
  • zaken1zaken1 Posts: 556
    I assumed that you replaced the timing belt since the time it last ran. If that is indeed the sequence of events; then it is likely the cam is now not timed properly (even though the marks appear to have been correctly lined up) This means that either there was an error made in lining up the marks; or the woodruff key on the crank pulley sheared off when the pulley was reinstalled, so now the timing marks are not reading the true crankshaft position. The other possibility, which I mentioned in my previous post, is that the stock marks may not be the proper place to time it with the new cam. If that is the case; you'll have to ignore the marks and set the cam position by splitting the intake and exhaust valve overlap (as I previously explained).

    Whatever the cause; it is futile to try to make the engine run with such terrible compression. If your gauge is correct, and the low compression is not the result of the cam being out of time; then it is caused by burned valves and/or worn piston rings. If that is the case; the compression may have finally dropped below the level which was necessary for the motor to be able to start at all.
  • zaken1zaken1 Posts: 556
    The ignition module is a small black plastic box with two mounting bolts and a three terminal electrical plug on the side. It is probably mounted on the firewall, near the ignition coil. Here's a link to a photo of that module ( These modules are one of the most reliable parts on the car; so I really doubt that it would be worth replacing it without first proving it is defective.

    But some very worthwhile tests you could run are to measure the voltage at the positive primary terminal of the ignition coil WHILE THE STARTER IS RUNNING. Testing the voltage at the coil when the motor is stopped will not give you meaningful information; because there is essentially no current flowing through the coil primary when the crankshaft is not turning. (The module automatically shuts the coil current off when it does not receive trigger signals from the crank position sensor). A defective camshaft position sensor will also shut the spark down.

    If you find that the 12 V supply voltage at the high side of the coil drops way off when the starter runs; this means that there is a resistive connection in the ignition switch or the battery cables; or the battery is too weak to start the motor.

    If the voltage remains unchanged at the coil during cranking; then the module is probably not receiving a trigger signal. You can create a known good trigger signal by momentarily connecting a 1 1/2 volt flashlight battery to the two wires that go to the crank position sensor while the ignition key is in the on position. The flashlight battery polarity may need to be reversed to create a good spark. If this test creates consistent sparks from the coil; then the coil is not receiving a signal from the crank position sensor. The clearance between the crank sensor and the trigger wheel is very critical. I have heard of people who replaced the oil pan gasket with a thicker one; and found that it shut down the crank sensor (because the thicker gasket moved the sensor further away from the crankshaft).
  • race003race003 Posts: 2
    I got back to your post late zaken , thank you for the info I will run the tests tomorrow.
  • geo26geo26 Posts: 1
    96 Geo Metro with 174,000 miles cranks but won't start when it rains.
    Facility tested battery - great
    Facility replaced starter Saturday - it rained Monday and would not start. Today it rained and again won't start. In between it did not rain and started.
  • have a 95 geo that will not start, will not even click the cylinoid battery at 12.89 V, fuel pump comes on every time, lights are intermitant may or may not come on or work, then when the key is turned to start it looses all power every thing gos off, all fuses and relays are good, hope some one can help .
  • zaken1zaken1 Posts: 556
    These symptoms are a classic sign that the battery posts and the inside of the cable clamps need cleaning. It is also important that the ground cable is connected to a bolt that threads directly into the engine (NOT into a bracket) and that there is a second ground wire running from the battery negative terminal to a bolt in the inner fender. If the second ground cable is missing; it will be necessary to buy or fabricate one and install it. After cleaning the battery posts and cable connectors; the cables should be reinstalled and the clamps tightened until they cannot be moved by hand.
Sign In or Register to comment.