85 SE with 2.8L V6. I have been triing to solve what appears to be an over rich problem. After reading what others have gone through, I replaced the fuel regulator (I had replaced the fuel pump one week prior to my problems). Problem still not solved. I took a car to a mechanic to run the computer codes. He says that it will only flash 12. The check engine light does come on, I don't understand why there are no other codes showing. I really what my car back. Any help PLEASE!!!!!!!!!!11

I would check the cold start switch, It may be leaking . It only works while the starter is engaged, but if the vale is leaking then it would cause a rich condition. also it would not show a code. Take it out and plug the hole, if it runs good then you have found the problem. I noticed that you are in calif. so you really don't need it.
Don

I have thought about the cold start valve. IT seems to start just fine at first, runs for about 3-4 minutes then the problems start. If I remove the cold start valve, I presume that the hole in the intake manifold can be plugged with a standard type plug. How do I plug the the cold start valve itself so that fuel does not spill out?

Try replacing an O2 sensor. Possibly this canbe throwing off prpoer readings...It is only like $20.

Hank

Try starting it at night and see if the manifold glows cherry red. Mine was doing that and was not giving any codes what-so-ever, and it kept fowling out the sparkplugs.

There are several threads in the archives on "glowing manifolds" if it is.

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"Never offend people with style when you can offend them with substance."
--Sam Brown

I have never had one of these cold start valves off, but i would have to think that you would have to undo the fuel line also that goes to it and plug it. I tried to find some pictures of it but could not find a picture of the valve. maybe someone else can help like OGRE.
Don

We think that we have found the problem to be the MAP or MAT sensor. However; my machanic can not find the location of the MAT sensor. Does anyone know where it is?
Thanks

Here:

Next to the vapor canister on the opposite side from the battery (under the louvered vent.)

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"Never offend people with style when you can offend them with substance."
--Sam Brown

You guys are too cool!!!

I I usually go to Paso on the weekends and would be glad to meet with you and go over your car and answer any questions you may have. Send me an email at terry@tgowens.com and let me know how to get in touch with you.......

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Classic Fiero Owners Group International

Code 12 can also be a problem with the ignition system if you can get a code 12 to come up with the engine running.

Phil Pettus

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GTDude's 86GT

Thanks for everyone's help. tgowens: We already know each other. You knew my wife at Kragens, and we have both been at your shop up north. I will keep trying anything and everything to get my car running. My mechanic was informed that on the earlier V6 models, that if an injector shorts out and sticks open that it could fry the ECM. Anyone know anything about this? Also, the car seems to run fine for about 3 minutes before the trouble starts. I am thinking about the temp sensor. Funny thing is that the codes won't give us a problem, just keeps flashing 12. The O2 sensor has been checked and appears to be ok. It says that the engine is running rich -- we already knew that.
Steve

Steve, I knew that was you. I was just thinking that maybe we could get together and get your car going good when I am down there.

I have yet to see a sticking injector fry an ECM. It is possible that you have a malfunctioning injector which can cause it to run rich (I had that happen on one of my '87GT's - when I removed the fuel rail I found 5 Bosch injectors and one Lucas injector - the Lucas was causing it to run rich.) Let me know if you need any 2.8 injectors, I have a bunch I'll donate to your '85.....

It could very well be the coolant temp sensor that is the culprit -- and that is an easy thing to change. And, you said that the O2 sensor is good but, have you changed it? If not, I would, I change mine once a year.

For the code 12 - that indicates the engine rpm reference signal with the key on and the engine not running. The reference signal also triggers the fuel injection but if the signal isn't present the car won't run so I doubt that the code 12 is the problem. It is possible for an O2 sensor to fail without giving a code 13.

Make sure also that the wiring from the sensors is in good condition and the plugs are not loose.

Tell your wife Hi for me, haven't seen her the last few times I was in there so I guessed she is no longer there.

quote Originally posted by ichifiero: I have thought about the cold start valve. IT seems to start just fine at first, runs for about 3-4 minutes then the problems start. If I remove the cold start valve, I presume that the hole in the intake manifold can be plugged with a standard type plug. How do I plug the the cold start valve itself so that fuel does not spill out?

I know that you already traced it to the MAT sensor (I hope that's all it is!), but if you want to disable the cold start injector just unplug it. There is no reason to completely remove it.....then you will have fuel leak issues to resolve. The plug is identical to the injector plugs, so just push in on the metal clip and pull off. Getting it back on will be a PITA......the distributor is sort of in the way (but it isn't impossible).

At any rate......by unplugging the cold start injector you can at least eliminate it from the list of possible culprits.

Good luck!