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intermittent problem, need help; Very intermittent problem no codes
Topic Started: Aug 8 2014, 07:01 AM (957 Views)
MightyMonte88
New Member
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Hey guys new to the forum here, having allot of trouble with my metro and need some help. The cars a 1995 Geo metro LSI 1.3L auto, 114,000 miles. Been a solid runner since i owned it at 64k millage.

Recently i've had to replace the timing belt and map sensor, other than that i just keep up with basic service.

The problem i'm having is that intermittently the car trys to shut off and "buck" when im driving, i'll come to a stop light and shut the car off, start it back up and it's fine for anywhere between 1 mile to a day later. In the mornings the cars pretty much ok, and i make a 45 mile trip to work and it normally doesn't act up, today it started acting up right as i pulled into the parking lot of my work.

On the way home it usually starts doing it about halfway home. Last night i let it sit and idle once i got it home, and i noticed what sounded like a very VERY slight popping sound, as if it where out of time. So i checked the timing belt, no problems there and it's still in time. Did a compression test and everything checks out, got a 175 - 180 PSI on all four cylinders. I checked voltage at the battery, key on i'm at 12.7, running it sits between 13.6 and 14.1 .

When this problem first started i swapped the ignition coil for a new one on a whim, hoping it would be a quick fix but was not. So i switched back to the OEM coil for now. I'm in the dark because i cannot get the car to throw any codes, the check engine light will not come on. I tried replacing the bulb but it just won't work.

I tried swapping the ignition module as well, no prevail so again i put the OEM module back in.

I'm going to test fuel pressure next, can anyone tell me what the correct key on/ running fuel PSI should be for this car??

After that i'm going to check the coil with a meter, as well as the TPS.

At 85k millage i replaced the spark plugs, wires, dizzy cap and rotor cap. radiator (corrosion issue) , fuel and air filters. as well as the PCV valve

Any help would be MUCH appreciated, i need this car to get to work and this problems snowballing into a real nightmare :x , if i lose my car i lose my job....
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Metromightymouse
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Powdercoat Wizard

On the check engine light, you need to track the issue down. It's either a bad wire or connection somewhere or an indication of a problem in the ECU. Do you have a FSM?
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MightyMonte88
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No i don't have an FSM, can't seem to find any online refrences either..

I'm pretty sure it's a bad connection, the check engine light has been inop since i bought the car with 64k millage two years ago
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Metromightymouse
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Powdercoat Wizard

Find and order one. They are usually available on Ebay for less than $30 and it is invaluable for working on this car. I am not at home so I don't have access to mine at the moment. You need to trace the output from the ECU and confirm it is sending the signal to the light and fix where the issue for that is. That light gives you access to the codes in the computer and is invaluable for troubleshooting an issue like this.
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geogonfa
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:gp
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MightyMonte88
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Alright i'll trace the issue after work today, or during lunch. I'm at work right now, if yall don't mind can one of you lookup an ECU for a 95 metro LSi 1.3l Auto ?
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Metromightymouse
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Powdercoat Wizard

If I don't get to involved in my trans issue when I get home, or distracted and forget, I will pull out the big green book and see which terminal it is for the CEL light.
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geogonfa
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Just my $.02...99% of the time the ECM is not the problem...usually it is a ground, open wire, or a bad sensor...after you get the check eng. light working you can get a better idea of where to go from there....here is a good post to start:
http://geometroforum.com/topic/638390/1/#new
:type
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Metromightymouse
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Powdercoat Wizard

I agree it isn't likely the ECU as the car has run for a long time without the light, but it is one of the indicators of a failed ECU. More likely a break in a wire between the ECU and the light, or the light and ground or 12v, probably 12v since most things are switched to ground by the ECU on this car.
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MightyMonte88
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Thanks guys, this has been a real headache so far. The only place i have access to the internet is at my work, i'm cut off from the world when i'm at my house so i have to reference and save as much info to this PC as i can
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MightyMonte88
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caught a second in between services here and ran out and swapped the bulb again to verify it wasn't just a bad bulb out of the box, still not light or codes with a fuse in the diagnostics port. If anyone can reference me some info on how to isolate and check the signal wire to the light from the ECU that would be a huge help
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Metromightymouse
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Powdercoat Wizard

Ok, pin 18 at the ECU is the MIL pin and the wire should be a purple with yellow stripe. If you unplug the ECU and put a volt meter between pin 18 (on the wire side, not the ECU) and ground it should read 12v. It is a purple with yellow stripe wire all the way to the cluster. If you have 12v at pin 18 with the key on then it may very well be the ECU. Use a jumper wire between pin 18 and ground and the MIL should light, that would indicate some issue with the ECU. If that isn't it you will need to check to find where you do have 12v. The MIL gets power through the IG Fuse and it should be a black wire with white stripe going to the cluster. There may be more than one black with white stripe wire into the cluster, if you follow the trace on the back of the cluster you should be able to figure out which one it is. Pick a place to start and check for 12v on either wire with the key on. The wire is supposed to be hot all the time with the key on and the ECU provides the ground. You are looking for a place where there is not 12v after finding where there is 12v. If the problem is in the purple/ yellow wire you will have 12v at the cluster and the purple/ yellow wire pin at the cluster but not at the ECU. If it's in the cluster you will have 12v at the black/ white wire pin at the cluster but not at the purple/ yellow pin. When you find where the break in the circuit is, fix it and the MIL should work.
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MightyMonte88
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Thanks a million friend, i'll get back o you guys somehow over the weekend with what i find
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Metromightymouse
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Powdercoat Wizard

Good luck, good hunting!
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ssssteve
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Might be cataletic converter. Sorry i cannot spell it.
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