Its a 305 TPI engine, everythig has been changed but car still dies out after 5 minsof running. Wondering if it could be the ECM, anyone know what coulod be the problem.

New ignition (all MSD)
New fuel pump
New ignition module
New TPS

 

what happens to the oil pressure right before it stops running?

 

Im not sure , what could be the problem if the pressure drops?

 

there is a oil pressure switch which will kill the engine if the pressure drops real low.

Not sure at what PSI it will cut out at though, maybe 5 or 6 PSI.

 

Ahh, do you know where the switch is located? Is it the oil presure sending unit?

 

http://www.chevythunder.com/fuel%20i....%20pg%20B.htm

this is a link to a good site, a lot of useful information....

pic of the switch (left) and sending unit (right).
they are located on the back of the block, drivers side.

 

Cool thanks for the info, I will definatley look into it & Ill let you know how it goes.

 

no problem
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no problem

 

Karl, the oil pressure switch does NOT sound like your problem now.
And let me clarify one thing out real quick (even though we discussed it in another thread) to avoild confusion: the oil pressure switch is NOT a shutdown switch for the engine in the event of low oil pressure.
And on the 90+ engines, it will be located on the block just above the oil filter. It is integrated with the oil pressure sensor too so there are not two sensors anymore, just one.

Anyway, Karl, you need to tell us more about how the engine shuts down:
- does it sputter to death?
- does it just quit like if you turn off the ignition?
- can you restart it after?
- and if so, how long does it run after?

Did you measure/check fuel pressure?
Battery voltage?
What's the temperature of the engine when it shuts down? Does it feel like it's overheating?

Your answers would give us something to go on.
Lou

 

What is the fuel pressure at startup and when the engine shuts down?

Maybe the fuel pump is overheating and shutting down,,, just a guess, but its a very important point in your case.

Whenever the engine has trouble starting, or no start, or shutting down after x minutes, the first thing that you should check on an EFI car is fuel pressure.

EDIT: BTW, ECMs will not work at first then quit x minutes later, either they are good or bad, they do not cycle good bad good bad etc. So, dont buy another ECM. You could pull one out from a similar car, and try it, but I think it is a waste of time.

 

k this is all I know, I dont have the car with me, its just wha was told to me.

--It dies out like when you turn ofthe car, no sputtering
--It starts again, then dies out after 5 mins.
--Bat voltage don't know
--Fuelpressure don't know

This is just what I kno when I went to look at the car. The kid said it just happened out of the blue. It took hin like an our to get home instead of the usuall 20 mins. cause it kept dying out. I'll try to find out more from him.

 

Hmmm, based on this information, I would tend to rule out fuel or voltage.

This might not be easy to troubleshoot. Usually, if a car dies, it can't be restarted for some time. That way, you have time to look for lack of fuel, spark, timing etc. In this case, that cannot be easily done.

Did the kid tell you when this started happening? What did he do to the car just before that?

Is the shutdown interval shorter if the car is driven?
Does the engine start immediately or does it take some cranking?
Does anything else shutdown with the engine? Like lights, radio, etc?

Lou

 

heres what he did to fix it
--new coil
--new pick up coil
--new ignition module
--new re wire
I'll try to find out more info from him when I get a chance.

He said he has to wait a while to restart the car, he said it has to cool down. I don't know if he means it overheats wich I don't think it does. He wouldn't push the car like that, it was his baby.

 

only thing i know of to do that is the ignition module. gets hot, shut down , cool off runs, heats up shut down. take to autozone have check for free

 

Good info, Karl, now it sounds like something is overheating and needs to cool down. I originally thought that the car could be restarted immediately which would be a whole anther problem.

I agree with George, one possible thing causing this could be the ignition module in the distributor. It can be tested at AutoZone. If it doesn't have enough heat transfer paste underneath, it will overheat and shut down.

Test for spark after the car shuts down. If there is none, it could be the ignition module (also called ESC - Electronic Spark Control).

Lou

 

Ok I'll check into it, we don't have an Auto Zone here, just NAPA, Checkers & some other spots. He changed the ignition module thinking it was the problem, but the problem is still there.

 

Hmm, if he already changed the ignition module but the car still behaves the same way as before, we can rule the module out.

What else is there that can overheat in 5 minutes and shut down?

As I asked before, what's the temperature of the engine when it shuts down? Some engines can overheat in 5 minutes easily. And the computer shuts them down to protect them. So if you can check the temp gauge, that would help. Also, if you can open the hood and "feel" how hot the engine is (it might be hotter than the gauge says), that would help too. What if there's no coolant in it? It would heat up badly and the ECM would shut it down. (just clutching onto straws now)

Lou

 

Well if it was less than 5 minutes to restart I would say maybe stuff was getting stuck in the fuel sock etc. Or maybe vapor lock?

I had an issue w/ my pickup coil, but it was missing before it would stall/die.

 

Lou, can you tell me more about the ESC module? I'm having an ongoing no-spark issue for the last six months. Please clarify, is the ESC module the one located under the cap?
See, my car used to be TBI, and it had the module under the cap, but another, probably 2" square module located on the relay bracket on the drivers firewall.
I converted to TPI a few years back, and the car has run great. I used parts from a wrecked but running 92 Z28. The thing is though, I don't have the other module on the firewall like when it was TBI (but I remember it was ignition related). Is this thing's function built into the TPI ECM or do I need to keep looking for another module? I don't remember there being one at all...

Sorry to hijack the thread!

Dave

 

Dave, your new TPI system does not need that extra box, you're good.

Karl, have the kid check the fuel pressure. I just realized he hasn't done that yet. Although, since you said that the engine just quits (doesn't sputter to death), I would rule out fuel starvation. But it still wouldn't hurt to check the fuel pressure.

Lou

 

 

Thanks Lou I'll let him know, probably this weekend, I'll keep you posted.
Thanks again.

 

He said theres fuel pressure & oil pressure & it doesn't drop b4 dying. The just shuts off like your turning it off. Could it be a relay or ECM problem?
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Also where would the fuel pump relay be located?

 

Try this:
- unplug the 4-prong connector on the distributor (there should be 4-prong and 2-prong)
- crank the engine and check for spark
If there is no spark, it's in the distributor and not the ECM.

Lou

 

So it could be a bad dizzy if thats the case?

 

Yes, IN the distributor. Either the pickup coil or the ESC module.
Those two CREATE the tachometer pulses and send them to the coil. So if either of them is bad, the coil won't get grounded and produce spark.
Well, ok, so if it's not the distributor, it can still be the coil.
But you can eliminate the coil easily if you have a second one. Once the engine dies, replace the hot coil with a cold coil quickly (takes 20 seconds). If the car restarts, it IS the coil.

Lou

 

it sounds like the feul pump is over heating which i beleive is an in the tank feul pump, How much gas dose he have in the tank?, if it is low tell him to fill it up and try it again since the feul cools the pump

 

So we can rule out fuel.

Well, to rule it out completely, one could spray some carb cleaner into the intake after the car shuts off and try to restart it. If it starts, it would be a fuel problem. That would be the 100% test.

Karl, any update? I forget, is the kid getting a spark?

Lou