mrmtrtrnd

1993 6 speed
While driving at about 40 mph the engine died like it lost all juice, no sputtering or missing just went dead. It would turn over fine but not fire. After setting about 5 or 10 minutes fired right up and ran and accelerated fine for about 10 minutes then died again, like the first as though the key had been turned off. After sitting it fired up and ran fine before dieing again. Each time it started it ran a shorter span of time until now it will not fire at all.
Any ideas where to start to find the problem without just throwing parts at it until I stumble on the right one.

Disarray_kid

Does the motor try to turn over or make any sound when you turn the key?

mrmtrtrnd

The motor turns over just like always but not fire.

Disarray_kid

I'm thinking it in the fuel or more in the way how the fuel is pimped into the motor.

your gas pump could not be working

I had this happen to me with my Firebird.

has this happen before or did it just start this?

mrmtrtrnd

Never had any problems what so ever. I turn key on and let the fuel pump build pressure first then try to start. My first thought is electrical because the way it died without any sputtering or missing and the fuel pump is still running. I know the pump could be bad but I would expect something other than running fine one minute then dieing the next.

Disarray_kid

any warning light come on when it did this?

mrmtrtrnd

No not a one.

Muffin

Assuming you ment it suddenly quits,no sputter, your problem is most likely ignition. Pull a plug wire and check for spark, or use a timing light. If you have no spark my first guess would be the ignition control module in the distributor.

TWISTERUP

It does sound like the ICM---on your LT1 it's located at front of right side head--on the bracket next to the ign. coil.

runner140*

Fuel pump give up the ghost? Mine did with simular symptoms.

mbowers13

My guess is fuel pump bad.

Good thing is: It only takes two things (besides timing) to make an engine run - gas & fire. If you've got a spark, must be no gas.

jaa1992

Might need the coil as well.
I was comming home from work one day a couple years ago. Engine got real hot from sitting in trafic and engine sputtered and car came to a stop. After getting it towed home I thought for sure "opti", a friend with a 92 suggested changing the coil and icm and see what happens.
I did and the car ran fine for anouther 8 months before the waterpump took out the opti.

mrmtrtrnd

Hey guys thanks for the help, checked tonight and had no spark. Tomorrow I'll pick up a ICM and Coil and put them in. I just needed a place to start looking and work from there.

Ryan59

Just seen this post. My guess would have been the Ignition control module also. Hope this fixes you up.

mrmtrtrnd

Hey Ryan what have you been up to. I let the car set a week before I even posted here. Instead of farting around I should have been working on this thing from day one. Hope that gets me going again because I haven't driven it much the last three weeks .

Ryan59

I've pulled mine out of the storage unit on a few nice weekends to charge the battery & run some gas out of it and refill the tank.

We need to get together soon, a weekend or something. I'm getting ready to change heads on my car and finally put that Hotcam in it.

Duntov85

Have someone experienced with an oscilloscope actually test the components and determine a reason for replacing stuff. Replacing things by guessing is expensive, time consuming, and aggravating.

With that said, I suspect you could be losing the distributor reference signal which tells the ECM the engine is running, but that is only a guess.

A good shop will diagnose the problem correctly and only replace a part that is PROVEN to be faulty by testing - not guessing.

pcolt94

I agree at first thought it has the signs of a bad ICM. On the surface it does sound like a heat related problem.

I would probably check for spark off the coil right when the problem happened to ascertain if you’re in the fuel or spark category. If you have no spark, then I might bet on the ICM. Having said that, the 92-93 have a history of defective and weird problems (killing spark) from the ECM. Let’s hope that is not the problem but just keep in the back of your mind for now.

I would also hang a fuel pressure gauge on it or drive with one on especially if you did have spark from the coil.

The ECM might also affect the drive pulse for the injectors and completely shut it down. Just another wonderful item to remember. So you might end up checking injector pulses also.

Al Borman

Duntov(love that name) mentioned it in above post, if the PCM does not see low resolution signal pulses from Opti, the PCM will not send a signal to the ICM(which in turn fires off the coil to appropriate cylinder). You can rule out the Opti as being the problem by getting your history error codes, which takes only a few minutes by shorting ALDL PinA and PinB. If you get one or both of the following error codes, then your Opti has taken a dump:

16 - A low resolution pulse was not detected by ECM within 720 high resolution timing pulses.

36 - ECM detected less than 60 high resolution timing pulses between each low resolution pulse for 5 consecutive cycles.

Your ignition system in your '93 is a closed loop feedback system starting with the Opti ==> PCM ==> ICM ==> Coil ==> Opti ........

If you can't isolate a problem directly(bad ICM or Coil wont throw error code), the process of elimination is the next best thing.

mrmtrtrnd

Thanks for all the feedback. I've been under the weather this week so I haven't gotten anything done on the car yet.