Well, here is the story. Car has been running great, no problems.
Then all the sudden, start it up, runs for 10 secs and fizzles out.

I can start the car, but it only runs for 10 second or so.
If you step on the gas and keep reving it, it will stay running, but soon
as you let go of the gas, it fizzles out.

Took to a local shop, he is a good shop, has a couple of race cars.
He thinks it might be the opti-spark and distribution system, but then
he said it would cost $1000.00 dollars to replace since you have to
take apart the whole front of the motor to replace.

Now, I don't want to spend $1000 if he is wrong, but the car cannot run
long or stable enough to get a code out of the engine.

Is there anyway to be sure that it is the distribution system / opti-spark?

Any advice is appreciated.

 

Sounds like the IAC is not working correctly. When you first start the car the IAC setting is a high step value, then it decreases until it finds the pcm programmed idle setting which takes around ten seconds. The IAC is what controls the idle. Are you getting a trouble code?

If this stalling condition is repeatable and consistant; running smooth and then crapping out after the same time period, it's probably related to a sensor or servo which the pcm is turning on as part of the start-up sequence.

A bad opti will give a trouble code unless it is a physical defect such as a broken rotor, but a physical defect should exibit itself all the time. Same for wires. Wires usually show themselves with high humidity conditions first, and they too would not be ok just for the first 10 seconds of start-up.

First suggestion would be to clean the carbon out of the IAC passages. Only cost you a can of carb cleaner. You can find dozens of posts here where guys have changed expensive parts and not found the problem. Your mechanic is probably good and taking his best guess. If you do let him go ahead with repairs ask him to do the wires first and see if that fixes it. Wires will only last so long anyway and is much cheaper than an optispark. Good luck.

 

OK, thanks for the advice.

But to be clear on something, when I start the car it starts perfectly fine, run
for about 5 -10 seconds a the idle just quickly diminishes.

Now, if I rev the accelerator before it total dies out, I can keep the car running.

Sometimes it will run a VERY low idle (about to stall) for a few seconds longer.

I guess the point I am trying to make, is that I can keep it running by flooring the acclerator.

Tom

 

What if he unplugs the IAC motor to bypass it. That would disable it, it will set a code for sure then, but it might let the car continue to run.

And do you REALLY have to floor it, or you just have to feed is some gas to keep it going (like part throttle will keep it running)?

 

Hello,

I would say you have to push the pedal down 1/3 or so to keep it running.

What I am not sure of is if it really is the opti-spark, hate to replace that if
it does not need replacing. And its strange how it was running perfect and
now is running like total crap.

But what is even stranger, is the it starts up fine and runs perfect for a few
seconds and then loses idle very quickly.

Tom

 

like brutal bird said...the IAC is going to allow extra air in when initially started for about 10 seconds before going down to normal PCM programmed idle (the IAC is what lets air in for the engine to be able to idle when you aren't pressing the gas pedal since your throttle plates are closed off not letting air in the engine). So i would definitely check that out first. I'm not sure why an opti would let the thing run for 10 seconds then die that doesn't make much sense to me.

 

Try unplugging the electrical connector from the IAC motor and see if it will run.

 

OK, I found out what is was.

The air box assembly and parts of it literally fell apart.
Debris from the airbox was stuck in the throttle body.

But, no big deal I was putting in a CAI anyway.

Thanks
Tom