2.3 quad 4 ignition problem

[Rockett30]

The other day just as I was getting off the freeway, I lost a lot of horsepower. When I stopped, the car would stall out. After I got home, based on some information I received from a co-worker who had similar problems, I pulled the IDI ignition cover and checked the spark plugs. Cylinders 1-4 were flooded with gas and 2-3 were clean. Assuming that the problem was with the coil, I replaced the one for 1-4. That didn't fix the problem. I then proceded to replace the coil housing, all 4 spark plug boots and the ignition module. All parts used were new. The car is still only running on cylinders 2-3. Anyone out there know what the problem might be?

Thanks

[GMMerlin]

Check the wiring from the IDI module to the coils. If there is an open on that wiring the effected coil wont fire.
Also, are you sure that you replaced the coil for 1-4 and not 2-3?

[Rockett30]

Originally, I swapped both of the coils to see if the problem would move fro 1-4 to 2-3. Nothing changed. I decided to replace the coil anyways, just in case. I also rang out the harness to make sure it was ok also. Its fine. I was kind of curious as to how the crank position sensor works with the ignition module. You'll have to excuse me, I'm an electrical engineer that likes to work on cars.

[Rockett30]

I just did a bit of brainstorming....is it possible that the computer is the one with the problems? I can get a new(remanuf) one for $75, but I want to make sure before I throw any more money at the problem.

[GMMerlin]

According to the schematic (since I don't know the year of your car, I'm basing this info on a 96 schematic), there is a control circuit for each coil from the PCM. A poor connection, open wire or a bad PCM could cause your problem

[Rockett30]

the car is a 1988 Calais

[GMMerlin]

If I can locate the 88 book, I'll check the schematic for it.

[Rockett30]

Well....it turns out that I'm and idiot and made an assumption. I did not check the obvious before I started buying parts. Today I verified spark to all the spark plugs. I pulled off the ignition cover, pulled all 4 plugs and put them in the rubber boots and laid them across the valve cover. Upon turning over the engine, I found that all plugs were sparking just fine. This means that I replaced all the ignition parts for no reason. I talked with co-workers brother-in-law and he suggested that I check the injectors. With nothing else better to do, I pulled the fuel rail with all 4 injectors. I had my wife turn the key to the run position and the injectors for #1 and #4 started spraying. Not good. Just to be sure that I didn't have bad infectors, I swapped 1 & 4 with 2 & 3. After turning the key to the run position, 1 & 4 started spraying again. Looking at the electrical diagrams in my Haynes manual, I found that both of those cylinders are controlled by the same single wire from the Powertrain Control Module (ECM). Looks like the ECM is telling the injectors to spray all the time which is flooding out my cylinders.

If I'm way off on this one, then I'll have spent another $75 for no reason because I just called the parts store and ordered another ECM.

I'll update later after I put in the new computer.

[Rockett30]

The new ECM is installed and it looks as though my problem is solved.

GMMerlin....thanks a lot for posting some replys and trying to help me out in my time of need. Looks like you've been a fantastic help to quite a few people.

Thanks again.

[jd4410]

I may be having a similar problem with my 91 Beretta GTZ. Thought I had a bad plug, the one I did not change last time because the old one was siezed! This is number 2 from the chain side. Number 1 is now also stuck! Number 3 and 4 are removable. After letting run a minute or so, still missing on one or more cylinders, I looked and number 3 and 4 plugs. # 3 was fine, #4 looked sooted and wet, and fuel vapor was coming out of that plug hole. I put a new plug in #4 and seem to run on all cylinders for several minutes up and down the driveway and then began to miss again. I would like to get it running as cheaply as possible and go ahead and sell it.

Does this sound like the Powertrain Control Module? Where is this one one the car, does it come from the dealer only? Can it be taken off a used vehicle? Any other tests I can try to verify the problem?

Thanks

[skauaihilo]

iam looking for the firing order for a 86'olds cutlass ciera with a 4 cyl.?