Hi All
I have a 1989 2.8 litre V6 Firebird whose engine has started to idle erratically.
The rev counter needle jumps around the gauge but the engine revs do not follow. However the engine seems powerless and whilst it does not stall it does not run smoothly.

Is this Spark Plug Foul?
What is Spark Plug Foul?
What can I do to solve this?

Many thanks

 

Not 100% but it sounds like the ICM, or ignition control module. Does it have a misfire? And does that misfire correspond to the tach jumping?

Also, do you have a book for the car? If you do there should be a page which shows all the different conditions of the spark plugs and what those conditions mean.

Always a good idea to have a book for the car.

 

Thanks for this.

What I did not write last time was that cables on the battery were loose and I tightened the connections. Have driven the car today and all seems to be ok now (until the next time)!!

 

If you still have the original fuel injectors you might want to check the ohms and see if they are your problem. Also check your fuel pressure regulator (FPR) to make sure it's not leaking. Good luck.

 

Thanks for the information - I assume that these are not "do it yourself jobs"?

 

The injectors really arent that hard to do, just take your time. It would be a good idea to grab intake gaskets for when you pull the upper intake off. Also if you dont have a digital multimeter to ohm your injectors, they arent really expensive to buy.

If you want to make things easier a book always helps.

 

Hearing the the tachometer is bouncing all around and your not gaining rpms in real time, it sounds like a ignition issue.

The ICM sends a signal to the tach and if your icm or even the little reluctor/exciter wheel on the distributor is having problems it will run terrible and send a sketchy signal to your tach and to the ecm as well.

I see your across the way but see if any parts stores over there can test your icm. Ignition control module. Also while you in the distributor area check that everything looks ok, as in there isnt anything loose. I had a reluctor/exciter wheel come loose last year and cause problems like you had. The difference is that I was in the middle of a burn out at the racetrack when it happen.....

Its a job that isnt too difficult with a little research.

 

Dear All

Thanks again for the advance. I will check around the distributor and have the ICM checked.

 

This is just a question. Is it possible for a bad ICM to cause a dead cylinder and a fuel injector malfunction?