Hey - could us some more of your advice on this forum. The problem is my 91 lumina occasionally stalls when warm and now is getting harder to start when warm only. Starts and runs great when cold.

After reading other complaints about the same problem on these earlier luminas I replaced most things that were recomended but with no avail. I have already replaced the ignition control module, the CPS, the fuel pressure regulator and PCV valve. ALso replace fuel filter and fuel pump relay. Also replaced plugs with new ones, wires are new too.

Last nite after relearning the idle the car was good and warm and after shutting it off it would not start. Well it fires and run for about half a second and dies. You can keep trying to start it but with same results, fires and dies. I have never been able to get this car to not start in the garage its always been on the road somewhere. I checked the fuel pressure at the rail and it was normal 34psi with key on /no start and about 35 or so when cranking. I unhooked the fuel pressure regulator vacum line and pressure jumped to 40 like it should so I am assuminmg the fuel pressure is Ok. Then i checked spark with a spare spark plug and layed it on the motor and it sparked even though car didnt start. The spark was blue but does seem a little weak. SO basically I have spark and fuel but it will not stay running. It only fires and dies. This morning after sitting all nite it started right up and ran great. Also I tried tapping on ECM last nite when car was running good cold before this problem reoccured but it ran great. Any help would be appreciated Thanks

Try heating up the ECM with a hair dryer while the car is cold, then see if the problem occurs, then you know what you gotta do.

Make sure all your grounds (Battery, motor, chassis) are solid too....

Yeah I thought about that. I can give that a try. I did feel the ecm last nite when car was failing and it is of course much cooler than anything directly on motor which made me think it could not be ecm but its worth a try. Thanks

Same guy here: when you say ECM you mean the black box on passenger fender well behind radiator fluid reservour right?? As i looked up price on Autozone .com and they give a price for a ECM 70 bucks and then also a ECC(E control computer) which I think is the main computer for 150 bucks.

I took your advice and heated up the ecm on the firewall with car running cold but could not get it to stall at all. Also tried tapping on it . I heated ecm and occasionally would shut car off and try to start it and it started everytime??

It is the cheeper ecm (70 dollars) so I think I am going to replace it anyway to eliminate that possibility.

Oh and I think I understand now that the ecm IS the main and only computer. I was thinking it was only for the injectors and there was a main computer inside the car under the dash. I think newer Luminas have their computers inside car away from all the elements.

I will let you know if the new ECM does the job.

I would look at the EGR valve. The EGR may be stuck closed causing the car to stall when warmed up. The EGR should be closed when cold, and open when warm. If it's stuck closed after the car is warmed up, it will throw off the fuel mixture to the point of not allowing the car to start/run. I wouldn't waste my money on an ECM yet, as I seriously doubt it's the problem since it passed the heat and tap tests.

I am glad I read this as i was on my way to the parts store. I already took the old ecm out of car but its pretty easy to put back on. I will look at the EGR first. I did clean the penum last weekend where it looks like the EGR would let some exhaust back into intake as it was restricted but not plugged. but I didnt check the EGR valve .

I am just wanting to get this darn thing going again as I dont know if I can trust driving this car anymore as it is such an intermitent problem that seems to be getting worse.
Thanks for the advice

One thing, that EGR valve is EXPENSIVE (like $200+), so if it's bad, ouch. But I'd hate for you to waste money on an ECM, only to find out it's another part you need, albeit a more expensive one.

Ok so how do you tell if The EGR is bad. ? I loosened it up last nite with car running and it wanted to die so I couldnt tell if any exhaust was coming thru the valve or not. I guess it shoudnt be with car cold right. Only should open up with car warm. I do have the right valve dont I? . Its close to the intake opening behind throttle plate in plenum on windhield side of plenum. Has I bolt and 2 nuts holding it on and then there is a sensor with wires on the end and also a metal tube 1inch or so in diam (about 6 inches) long going down to exhaust manifold.
I dont have a scanner but the check engine lite never comes on unless the engine actually dies but then it should come on right as the engine is dead just like on start up when you turn key on before you turn it to start all the dash lites are on and then go off when engine starts.

One more thing . This car has actually only stalled twice.(not that -that is good) The main problem is a very intermitent start up and usually when it acts up it has been driven for say 30 minutes(or good and warm) and then sits for 45 minutes or so and then when the conditions are apparently just right it will start and then instantly die Usually if you keep trying to start it, it eventually after 5-10 start/ die episodes it finally starts and acts like nothing has ever been wrong.Runs like a top.
If the EGR was bad and stuck wouldnt it act up while car is running cause I think you could drive this car till you run out of gas and never act up till you actually shut it off and then it sits awhile.

Do you mean the EGR affects start up signals to the computer and then apparently shuts off injectors.

Yeah 180 bucks at auto zone. Thanks again for everyones advice.

yes you have the right part. It's a 3-solenoid electronic valve, and if it's just starting to act up, the multiple key on/key off cycles will sometimes unstick it. It has no position sensor per say, so it normally won't trip a code.

Ok I finally got back to this . I took the EGR off last nite and it seems all the valves are not stuck as they push in easily. But this is also when the engine was cold. Perhaps one of them sticks when hot.Also all the passages seem clean and not carboned up. I did read in the Hanes that you could use a good scanner and check each selinoid individually but I dont own one. DO you still think it could be the EGR?

This car acted up on me big time last weekend as I had driven it 45 mins then let it sit again for awhile and when I came out to start it would not start. I had to let it sit for a hour before it would start and then it was fine but on the way home it started cutting out under acceleration but never died. Do you think ignition coils could do this? Break down when hot. They are the original coils with 185 k.

Coils are a possibility, as well as the Ignition module and ECM. All three will break down when hot, and cause your condition. Even though you changed the ignition module, it could still be bad.

I put 3 new coils on and a new EGR valve last nite so we will see. Ran fine on way to work today but then it did before . Has to be hot then off for half and hour or so before it usually acts up. Ill keep you informed if it fixes it.

Well back to square one. The coils and EGR DID NOT fix it. I called the shop and there going to take a look at it tomorrow. I cant beleive it could be 2 bad Ignition modules that have exactly the same problem but weirder things have happened.??? I did pull the codes and there were no fail codes stored. I also(against your advice did replace the ECM) but also no fix. I give up! It does act exactly like a bad Ignition module though. Or some other sensor. Maybe the shop can look at things better with their equipment hooked up to it when its acting up. It seems pretty consitent now. Just let it sit about 40mins after it is good and warm. Thanks for all your advice so far.

The crank position sensor would be my next guess, or a corroded harness somewhere.

Already did the crank sensor. yes the plastic sheathing around wiring harness is getting brittle and falling off- well not the wires but the plastic sheathing around it. i have replaced as much of the flexible plastic sheathing around it as i could but yet there are many places where you cant get to. Hopefully they can find it in the shop tomorrow. thanks

Yeah the car actually failed in the shop. Wouldnt start. They traced it down to the fuel injectors. Said the 2 they could get to, had unbalanced resistances. 1400 bucks to replace them all including labor.
I said no way I will do it my self. I will bug them first with car hot and see if i can find a bad one. I read a nother forum that said bad injectors is very common on these older luminas and if they short out when hot they will draw excessive current and then the computer will shut car down.Sounds like mine.
I had plenum off last weekend as I did replace the fuel pressure regulator. My question is how do you get injectors out. DO you leave them attached to the rail and pull all of them out as one unit ? Or do you take off the little clip on each injector and remove rail seperately and then pull each injector out seperatelly too.What if you want to only do one or 2 of them do you need to pull them all out. ? Also do you need to split the rail in to 2 halves and remove regulator too. I tried pulling on rail and injector assembly last weekend and even though they were loose they seemed very hard to pull up so i didnt mess with them. Sorry for so many questions. Thanks again.

It's easiest to remove the injectors with the rail as a unit, then remove the individual ones you are replacing from the rail. I would replace all the o-rings to prevent any chance of fuel leakage. Those injectors are pricey ($85 each wholesale), but attempting to charge you $1400 is rediculous. The upper plenum is pretty simple to remove, and the injectors are right there after it's removed. There are, I believe, 4 bolts securing the rail to the lower intake, and the two fuel lines to remove and the rail is in your hand.

Did you ever find the cause of this? I am having the same problem with a 89 bonnevillewith the 3.8L.

Ill have to get back to you on that as I am in the middle of working on it now. But did bug injectors lastnite with engine hot and not starting and did find one injector that only bugs 4 ohms. Rest were around 12 as I understand is normal.I am going to replace the one bad one and go from there.

Well, I checked my injectors, they are between 14.2 and 14.5 ohms. I am going to check them again later when it gets warmmed up. Also going to check my EGR out. I was told to cut a pop can and seal it off from the engine to see if it helps. I am ready to try anything right now. I have also noticed it idling a little rough also, does yours when it's cold?

Thanks for the info and help. Please let us know how your injector swap goes.

Well, my problem is not the injectors. I have a fuel pressure issue. Injectors checked fine when starting problem occurs. Bled a little pressure from fuel rail and it started.


Thanks for the info on the injector problem. Hopefully won't need it in the future.

Well the injectors seem to have fixed the problem. Its started twice now when it usually didnt before. I went ahead and replaced all the injectors as they do have alot of miles on them and dont want this happening again when another one goes bad. The one obviously bad one measured 4 ohms and the rest were all between 11 and 12. The new ones are all 12.8 to 12.9 so pretty close to each other.

Thanks for all the advice. This is my first time to work on a multi port fuel injection sytem and all the sensors that go with these newer cars..(old carburator man). Is pretty easy once one actually figures out the exact cause of the problem.(which can be tough sometimes) I have learned alot.