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Chevrolet/Geo Metro

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Comments

  • No problem: Go for it.
  • ggeeooggeeoo Posts: 94
    Be extremely careful that you put only 3.4 quarts of oil on a crankcase. Tustin Buick
    in California put 4 quarts in and the engine would fail on steep upward hills. Check
    and drain if you are putting to much in. I sold the GEO to State of Calif for
    1,000.00 I will miss the Geo it could still be at Pick your Part in Stanton CA.
    But they wrote Crush all over it.
  • Hello,
    I'm new to this forum. Lots of good info here. I have a problem with my Canadian built 94' Metro TBI 2dr hatchback. A couple of years ago it dropped a valve while crusing on the highway. I have finally purchased a Japanese engine off ebay. I dropped it in and buttoned everything up and now I don't have spark to the plugs. I don't hear the fuel pump either. This is a throttlebody engine with an auto trans. Could this problem be from a defective ECM or coil? The car sat for a long while (3 years) before I replaced the engine so, I cleaned all the grounds and even made new battery cables. I have replaced the dist. cap, rotor, plugs, and plug wires. I tested the coil with a test light. It has power but I don't know how much since I don't have a voltmeter. I don't want to buy a new ECM or coil just yet since I don't know if that's the problem. Any help would be appreciated.
    Thanks,
    Dan
  • Hi there Dan, if you can't hear the fuel pump, check to see if that ground is screwed in properly. It's quite well hidden in the rear of the engine, on top. Also check the relay for it in that black box sitting on top of the fender, driver's side.
  • mljwiremljwire Posts: 7
    Hi everyone.
    I am new to this sight. I have had 3 cylinder Geo's since my first 85 Sprint and I love um. I have always maintained them myself. But I am at a road block.
    The 95 has 150+K and was running fine except the idle got real rough and the idle speed repeatedly goes high to low (pulsing) some times at idle (when coming to a stop). I have cleaned the PCV and have tested the sensors and dash pots and everything seemed fine. The only thing I questioned was the TPS riestance was off from the manual I have but it seems to work and at $140.00 I do not want to replace smoothing that is good. I also have looked for vacuum leaks. I have not written sooner because I want to do the testes again so I could write a better detailed post but I have not had a chance. Also I am afraid I will get chastised because I have adjusted the forbidden screw (what looks to be an idle screw). In my defense I am from the old school and we did not used to have to worry about turning one screw ending the world. Any way with this screw and adjusting the throttle position sensor I was able to greatly improve the idle (although not perfect) of coarse you know this killed the gas mileage. I have tried to adjust it back with no success because of the rough idle. My next step is to do a compression test but the car seems to run fine other than the idle. I also had added cruise control years ago and heard that this may have harmed the ECU, could this be true? If so what would the symptoms be? Thank you for your time. Any one with any ideas on my idle problem and getting my gas mileage back up would be gratefully appreciated. Also any links for parts and repair for this car would be nice, especially on how to adjust the forbidden screw.
    Les
  • zaken1zaken1 Posts: 556
    Since I'm the person who posted the original warning about not messing with the idle air bypass screw, I now feel entitled to suggest that your current problem may be the result of something as simple as a carbon bridged spark plug gap. So before you get too involved in diagnostics, please be sure that all 3 plugs are the right type, and that they are completely clean and fresh. (On my engine, NGK plugs just never seem to run right). And if the distributor cap or rotor has a carbon track, or a crack on the inside surface, it can also create similar seeming problems.

    Otherwise, one item that may be responsible is the electrical or vacuum connections to the MAP sensor. This sensor is a black plastic box, which is mounted near the top of the firewall, on the passenger side of the engine compartment behind the air filter housing. There is a 3 wire electrical connector that plugs into the side of the sensor, and a vacuum line coming from the back of the throttle body mounting flange, that connects to a spigot which hangs down below the sensor. If there is a crack or a break in that vacuum line, it could cause the problem. Or if any of the terminals on the electrical plug have become loose or have bent and are making poor contact (as they tend to do when they age) this could also cause the problem. The same problem could also happen if the vacuum hose connecting between the spigot on the bottom edge of the air filter housing and the idle air control valve has come loose or is broken. Those are the five most likely causes.

    The setting for the idle air bypass screw is dependent on the setting for the throttle position sensor; if one of them is way out of adjustment, it becomes impossible to properly set the other. The GM factory service manual says that the TPS (ON EARLY MODEL STICK SHIFT CARS) can be adjusted with an ohmmeter and a feeler gauge. The early model TPS units can be identified by there being slots in the flanges under the two mounting screws. Later model TPS units, which are not adjustable, have holes in the mounting flanges rather than slots. I expect the TPS on your '95 model is not adjustable. But if it can be adjusted; try setting it exactly in the middle of its travel. That will be a good starting point. The resistance between two of the terminals on the TPS is supposed to switch between zero and infinity when the throttle bellcrank has opened exactly .015"-.020" away from the stop it rests upon at idle. The precise measurement is made by placing different thickness feeler gauges between the throttle linkage and the stop it rests on when it fully closes; until you find the size gauge that matches the linkage position when the TPS contacts switch. These 2 terminals will also switch again as the throttle position approaches wide open.

    Adjust the TPS BEFORE you try to reset the air bypass screw. The proper procedure for setting the idle air bypass screw is to have the engine fully warmed up; and, while the engine idles, slowly turn the screw in (clockwise) until the motor noticeably slows down or becomes much rougher. Turn the screw only about 1/8 turn at a time, and let the engine stabilize. Then turn it 1/8 turn further. Keep going in that direction until you reach the point where the idle quality has obviously become worse, then open the screw back out just until it becomes smooth. Don't be concerned if the idle speed seems to have become a lot faster or slower: The computer will normally put the speed back where it belongs, after it gets used to the new air bypass setting.
  • mljwiremljwire Posts: 7
    Thank you for the response. I have replaced the plugs, cap, rotor and wires. I need to check the brand of plugs that I have installed; I have read a few other threads suggesting that certain brands do not work well. The TPS is adjustable, I have done the feller gauge and reistance setup but moved it again trying to achieve a better idle. I will try it again. I also did mess with the MAP sensor and thought I was seeing some change. I will check the wires and the vacuum hoses again. I have been all over the throttle body and I do not see the idle air bypass screw. I am assuming it looks like an old idle air mixture screw. Or is this the same as the linkage stop screw? I adjusted the linkage stop screw, exactly where is this idle air mixture screw? I am going to print this and go over it again over the 4th weekend. Thank you for your help. I will let you know how it works out. If you have any additional response I would appreciate it.
    Les
  • zaken1zaken1 Posts: 556
    First of all; if you have not previously changed the idle air bypass setting, I would strongly recommend that you leave it alone. Resetting it would just add another uncertain element to the puzzle, and we have enough of those to deal with already. Once you are able to set the linkage stop screw and the TPS correctly, and also find what caused the rough idle and poor economy; the air bypass screw will work just as well in its current position as it used to do. If you change the air bypass setting while the engine is running badly, you'll lose your baseline; which will only make the situation worse. That screw position is super critical; it is set electronically at the factory, and does not normally need to be readjusted. The only time the setting may need to be changed is when the engine is modified or overhauled. Besides, most people are not sensitive enough or experienced enough to adjust it properly. That's why the factory hides it.

    But back to the likely causes of your problem. In addition to what we've already considered, I'd like to add four more items. One of them is that you may have gotten a tank of bad fuel. If the problem began shortly after you bought fuel, this would indicate that bad fuel is a probable cause. And if you bought it at an unfamiliar station, it becomes that much more likely. In that case, you'll have to drive until the fuel in the tank is almost all gone; and then fill up with known good fuel and drive until it smooths out, before readjusting the settings you've changed.

    A second possibility is that dirt has gotten into your fuel injector. If you haven't changed the fuel filter in 150.000 miles, this becomes highly likely. Your car has a fuel filter mounted on the underside of the frame on the driver's side, just in front of the gas tank (about even with the leading edge of the left rear tire). There is a metal skid plate under the filter, which is held on by 2 or 3 small bolts. Before changing the fuel filter, you must vent any air pressure that has built up in the tank, by removing and replacing the fuel filler cap. Otherwise, gasoline will spray all over when you disconnect the hoses from the filter. Even after venting excess pressure, gas will run out of the lines when they are disconnected. I wait until the tank is almost empty, park the car heading uphill, and use a pair of clean bolts which have a long unthreaded portion, to plug the hoses and stop the gas from running out. But this is still a potentially messy job. It may be worth paying a gas station to do it.

    After the fuel filter is replaced, I suggest pouring a full bottle of Chevron Techroline fuel injector cleaner into the gas tank, and driving at least 50 miles so it can do its magic. That is an outstanding product. It can be bought at Wal Mart, Checker, Shucks, Murray, or Kragen; or at Chevron and Standard gas stations.

    A third possibility is that the spark plugs you bought are the wrong model for this car. This sometimes happens if you get the plug number from a cross reference chart, or a store computer, rather than going directly to the plug manufacturer's listing for your vehicle. Also, contrary to popular belief, many brands of plugs DO NOT come pre-gapped. So it is important to be sure that you bought the right plugs and all the gaps were properly set before installation.

    The fourth possibility is that the ignition timing has been readjusted during the tune up; and that the instructions about disconnecting vacuum hoses and/or electrical connectors before resetting the timing were not properly followed. That would make it idle poorly, and ruin the economy.
  • zaken1zaken1 Posts: 556
    There is one other item that neither of us mentioned; which is highly likely to be the cause. The EGR valve may have stuck partly open. These valves get lots of carbon built up in them, which can make the valve stick. Whenever the idle becomes rough, this is one of the first things I'd look at. The valve can be cleaned by unbolting it from the intake manifold, and working the diaphragm back and forth, while spraying it with carburetor cleaner, and scraping out any visible deposits. When it appears adequately clean, compress the diaphragm spring, and then when you release it; you should see it move freely back to the fully closed position.
  • I don't have any way of analyzing the exhaust, and my '95 3 cyl 5 speed Geo gets only 40 mpg when driven mostly in rural driving at 35 to 50 mph. I think it should be closer to 50 mpg. Even after replacing the O2 sensor, making sure the timing is proper, the plugs are in good shape, the compression is good on all cylinders, the EGR valve is clean and there are no manifold leaks (there never were any) I am not able to improve my mileage. I stuck an oscilloscope on the O2 sensor and within a minute of startup it's toggling (albeit rather slowly) between 0 volts and .995 volts.

    The exhaust pipe is still black inside with a small ring of black around the outside end.
    I have seen only one other Geo in the area which had a very clean looking exhaust pipe. What am I overlooking?

    I'd be interested in hearing from other owners comments, especially from cars from 95 and earlier (pre dual O2 sensor models).

    Steve B.
  • zaken1zaken1 Posts: 556
    Steve,
    Your message sounds like one I replied to some time ago. Anyway, here are my takes on this issue. Right now, my 1990 5 speed Metro has a dark brown, dry coating on the inside of the pipe. It turns black in the winter months, when I only do short trips. This happens when the ambient air temperature stays below about 55 degrees Fahrenheit. At those times, my gas mileage in rural non freeway driving drops to around 40mpg. In the summertime, the rural short trip mileage goes up to about 47, and it reaches the mid 50s on freeway trips.

    There are several areas which could make the pipe turn black (which indicates an excessively rich fuel mixture.) One is if the stock 195 degree coolant thermostat has been removed, or has been replaced with one having a colder specification. Similarly, if either the EFI's coolant temperature sensor or the intake air temperature sensor has drifted out of calibration or has developed a resistive connection, it will cause excessive mixture richness.

    The mixture will also go rich if either of the mufflers have been removed, or if they have been replaced with non factory parts. Installing a non standard ignition coil can also create an excessively rich mixture.

    If there are deposits in the fuel injector, or on intake valves; they also can create a rich fuel mixture. The most effective product for removing deposits from those two areas is an exclusive chemical formula called Techroline, which is made by Standard Oil of California. It comes in a black bottle, and is sold nationwide at Wal Mart, Checker, Shucks, Kragen, and Murray auto stores. It is also sold by Standard stations and Chevron dealers.

    Two other things that can create an excessively rich mixture are using an unsuitable brand of spark plug (I've had best results with Autolites, and with Bosch Fusion {although the Bosch Fusions cost about $10 each}), or having a throttle position sensor which is out of adjustment. If your TPS is adjustable, mark the curent position, and try setting it slightly counterclockwise. If you go too far, it will cause a hesitation under moderate acceleration. Your exhaust pipe will tell you when you get it right.

    Joel
  • I have a 94' Metro 2dr hatchback (Canadian built) that I replaced the engine with a Japanese engine bought off ebay. I can't get spark to the plugs. I had the ignition control module tested and it tested bad. So, Ijust bought a new one for it and still nothing! The parts store I bought the module from said they didn't have anything in the computer for Canadian cars. However, the U.S.module looked exaclty like my Canadian module. So, I went ahead and paid the $90 for it hoping it would work. Wrong. Will this module work or not, or what else could the lack of spark be from? I need to get this thing back on the road quickly. Thanks.
  • zaken1zaken1 Posts: 556
    First of all, it is important not to confuse the country where the car was built, with the country where it was designed to operate. The earlier Metros sold in America were built in Japan, but they were nevertheless designed to meet U.S. specs. They were very different from the cars intended for domestic use in Japan. The same goes for the later model Metros, after production was shifted to Canada. There were two different cars built there; one intended for sale and use in Canada, and the other intended for sale and use in the U.S The emission label under the hood should reveal whether or not your car was designed to meet U.S. regulations. Since all U.S. model Metros of that era were built in Canada, the fact that it was built in Canada doesn't mean it is not a U.S. model. And that bit of information can save lots of confusion at the parts store.

    One unlikely thing I discovered about my Metro is that if I connect a jumper wire from the battery to the coil, in order to bypass any possible resistance in the wiring or the ignition switch; it cuts off the spark from the coil (even though the coil is getting full battery voltage). It appears this is intended as an anti-theft device. So, if you're not using the standard wiring to run the car's electrical system; this could be the reason you have no spark. And since you made new battery cables; did you include the auxiliary ground lead in addition to the usual battery negative cable, I mean the one that goes from the battery negative terminal to the bolt in the inner fender well???

    And then there is the infamous ignition disabling feature built into the seat belt system of Metros of that era. If a seat weight sensor either malfunctions, or detects any weight in one of the seats; the seat belt for that seat MUST be fastened; or the car will not start.

    If the fuel pump does not run, there may be a problem with the fuses in the fuse box under the hood, or possibly with a power relay. The fuel pump normally runs for about 3 seconds when the key is first turned on. After that, it runs as often as required by engine demands.

    This may sound obvious, but it has baffled many people: If the timing belt on your replacement engine has broken or come off, it will cause the distributor shaft to stop rotating. And then the coil will not produce any sparks.
  • Thank you for the response Zaken. What would be a good way to identify my Metro as a car built to operate in the US? I can't find an emissions sticker anywhere under the hood. I haven't made a jumper wire for the coil and I did make a new secondary ground wire to the fender. The old one was very corroded. Could there be any other grounds I'm not finding or that need to be cleaned? One of the first things I did when I got the new engine is to change the timing belt. So, I'm good there. I still can't hear the fuel pump when I turn the key. I have checked the fuses and they all seem to be good. I may have the relay checked to see if it's working. I will take the back seat out and see if the pump is getting power. I am at a real loss here. Thanks for the help. Could use some more though.
    Dan
  • mljwiremljwire Posts: 7
    You can quickly check your fuel pump relay by swapping it with another one that is the same number like I believe your head light relay. They are the same and should be in the same box under the hood. At least they are on my 95. I got home from the store by doing this. Other than that I suggest you take Zaken's advice.
    Les
  • zaken1zaken1 Posts: 556
    You can find out whether your car is a U.S. model from the VIN. That is the number on the plate on your dashboard, on the driver's side, by the windshield. If you give that number to the parts department at a Chevrolet dealership, they should be able to tell you if you have a U.S. model. If you can't get a satisfactory answer from the dealership, I would try calling a larger dealership, finding a more highly motivated employee, or contacting the regional customer service center for General Motors. Another possibility is to contact the Department of Motor Vehicles in your state, and give them the VIN.

    Sounds like you did a professional quality job on the battery cables! The fuel pump probably has its own dedicated ground wire, which goes to a point located near the pump. I have seen that connection on other brands of cars become corroded enough to stop the pump. So by all means unbolt it and clean the terminals. I doubt you can access the pump from under the rear seat. You'll probably have to do it from underneath the car. It doesn't require a hoist. I just remove the left rear tire, and support the body on a jack stand, to gain easier access. But it might even be possible to do it without removing the tire.

    Regarding the 'no spark' condition; it might be useful to see if there is any spark coming from the coil, rather than checking at the plugs. It also would be useful to go through the fuse box in the engine compartment, and see if you can light a test light from the terminals for the fuel pump fuse (at least; I personally would check every fuse and circuit in the whole box) There are lots of points in and around that box which are vulnerable to corrosion.

    And see if all the usual electrical accessories appear to be functioning normally: the headlights, taillights, brake lights, directional signals, heater blower fan, radio, horn, windshield wipers, instrument panel lights, and the 'check engine' light. If there is a pattern of failed items, it might be illuminating.

    Joel
  • zaken1zaken1 Posts: 556
    A few more thoughts came to mind. No offense intended here; but even though you just replaced the timing belt, have you taken off the distributor cap and looked to see that the rotor spins while the engine is cranking, just to prove that everything is still solidly connected???

    There is another part called an ignition pick up unit, which if it were defective could be causing this problem. But rather than throwing another hundred bucks at the problem, I think it is a better idea to methodically go through the steps that were previously mentioned, and eliminate all the other possibilities we can think of.

    There is a parts source called Rock Auto, which has an online catalog that includes photo images. I looked up your model Metro there, and found several different types of ignition modules. One of them was for Canadian vehicles, and the others were not. It was very difficult for me to tell the difference between the appearance of the parts; but my computer has display problems, and I have not personally seen your module. You might find it helpful to go to their website, and see if anything can be gleaned. Clicking on the blue icon in a listing will bring up the image.

    Joel
  • zaken1zaken1 Posts: 556
    Dan,
    I just thought of an easier way to determine if this is a U.S. model. Open the driver's side door, and look at the body panel just below the door latch striker. There should be a plate there, which lists the place and date of manufacture. If that plate contains a statement about the vehicle meeting Federal specifications; then it is a U.S. model. If the plate refers to Canadian specifications, then it is a Canadian model. And if there is no plate, then we have an ongoing problem.

    If you can find a serial number on the distributor, the parts department at a dealership should be able to determine from that number whether this is a U.S. or Canadian model; but it the distributor has previously been replaced, then there still would be a mystery.

    Joel
  • Thank you so much for the advice guys! I will try the headlight relay since I know they work. I did watch to see if the distributer rotor was turning to make sure the belt was still on. No offense taken ;) . That was one of the first things I did. I learned a long time ago to check the little things that would be obvious like that. It helps. :D A buddy of mine has a voltmeter that I could borrow this week. I'll check every fuse in the engine compartment. As for the battery cables, I am very picky and neat when it comes to that sort of thing. I rewired my 69' Olds 442 from bumper to bumper and made sure everything was neat and professional. Soldered and heat shrunk every connection. :shades: This Metro is new to me because it has more electronics to it. So I'm more confused as to what the problem is. I know it has to be something simple. I'm staying positive. Thanks again guys and I'll try the advice you gave. May have more questions though. LOL!
    Dan
  • I just went to the Rock Auto website. I must have the Metro XFI 61ci. L3 TBI model becuase they list the very same ignition module as mine in the XFI catagory. It has the same numbers on it and everything (J121). However, I just bought one from a parts store here. Oh well, I'll see if it will work. I also checked the sticker on the inside of the driver's side door just below the striker. It reads
    " MFD. By CAMI-AUTOMOTIVE INC. Canada
    Date 11/93
    This vehicle conforms to all applicable US Federal Motor Vehicle safety, bumper, and theft prevention standards in effect on the date of manufacture shown above.
    VIN # 2C1MR2462R6728129"
    So, I beieve this car was built in Canada but was intended to be operated in the US. Am I right? I also found the ECM (Engine Control Module) on their website and thought I'd see what mine has. They look the same but, I will call them tomorrow because the numbers on mine don't quite match the ones they list. I just want to make sure they are the same in case I need a new computer. Is there any way to test it? Can a parts store or a dealership do that? They cost just over $300 so I want to make sure mine is defective before I buy one.
    Dan
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