Engine shuts off as it comes to operating temps.

[chevybill]

Hey guys, I have a 92 half ton owned since new. Almost 300000 miles, as the truck warms up it shuts off just as if you turn off with the key. What are some things to check, radiator is full of good coolant. Starts right up when stone cold. Thanks for any input.

[speedygonzales]

Ignition module would be the first place I looked.

[chevybill]

Where is the ignition module?

[ChevyTech]

In the distributor.

Many auto parts stores in my area will test the distributor module for free if you bring it in.

Make sure when you install or reinstall the distributor module that you use heat sink compound under it. The compound helps dissipate heat from the module. Without it, the module will fail.

[chevybill]

Thanks for the replies, I will check on the ignition module.
Can I replace the ignition module without removing the distributor?
Is this piece under or beside the rotor cap?

[speedygonzales]

It's the piece the harness plugs into under the rotor. No you don't have to remove the distributor to replace it.

Make sure you don't confuse dielectric grease with heat sink compound. I've never seen dielectric grease in an auto parts store.

[chevybill]

I replaced the module and the truck still will not crank or run. I can hear the fuel pump with the ignition on. Other suggestions, right now I am thinking possibly some other ignition part? Please reply.

[Shady Rascal]

First things first before changing any more parts.

When it dies and won't restart, does it have spark ?

Get one of these from the parts store.



When it dies, unplug the handiest plug wire off of the spark plug, put it onto the checker, clip checker to a good ground, and crank the engine. Does it spark ?

If you do indeed have spark, it's time to check for a fuel issue. Remove air cleaner lid, put a good quick spray of starter fluid down the throttle body and see if it will start and run for a second.

It's either a fuel delivery problem or an ignition problem. Spending any further money on parts before determining which direction to go is a sure fire way to waste money.

[speedygonzales]

Originally Posted by chevybill

I replaced the module and the truck still will not crank or run. I can hear the fuel pump with the ignition on. Other suggestions, right now I am thinking possibly some other ignition part? Please reply.

Above it seems as though you are saying that since you replaced the module, the engine will not crank (as in starter not turning). You did say it won't crank or run.

How about you clarify the situation?

[chevybill]

Clarification, the truck stopped running all together. I replaced the module and nothing changed. Truck will not start, but I can hear fuel pump with ignition on. This is my current status.

[Shady Rascal]

Does the engine turn over when you turn the key to start ?

[chevybill]

Yes, engine turns over fine. Just no starting.

[Shady Rascal]

So this falls to checking spark and fuel like I mentioned above. It should be one or the other missing.

[chevybill]

It appears to be an ignition problem. Bought a spark tester and no fire to plug wire and no fire from coil.
When the truck was running, it would only run for about 5 minutes and shut off. It done this twice before quitting completely. Does this sound like an ignition coil gone bad?
All suggestions appreciated.

[95 S_Trucker]

Check to see if the injectors are spraying.

If you don't have spark and fuel injector pulse, You most likely have a faulty distributor. The PCM/ECM uses the signal from the distributor for injector pulse. Check for play in the distributor shaft. Check for damage to the reluctor/magnet.

[chevybill]

I know how to check for play in dist. shaft.
Someone tell me about the reluctor and magnet.
Location? what to look for etc.

Thanks

[TurnNBurn]

try swapping out the water temp sensor for the ecm. just had the same problem on a 94 k2500 couple weeks ago . Started good cold run it some and try restart and wouldnt go. new sensor and whammo fixed.

[chevybill]

Where is this water temp sensor? Close to thermostat? , engine block?

[chevybill]

Turnnburn, are you referring to the sensor in the intake manifold near the thermostat housing?

[chevybill]

Temp sensor did not fix my problem, whatever it is.
I can hear the fuel pump when the key is on.
I tried some starter fluid , with no luck.

[TurnNBurn]

yes the temp sensor is up by t stat. the truck we had acting up like that was either that , ignition module or ecm. when we watched the live stream data the timing was taking huge swings 50-60 deg changes in an instant.

[95 S_Trucker]

Did you ever check to see if the injectors are spraying?

Did you ever check the distributor for play in the shaft?

If you don't have spark AND you don't have injector pulse, its because the PCM/ECM does not know the engine is cranking. The number one cause of that is a faulty pickup/magnet problem in the distributor.

To clear things up because there is some confusion in earlier posts:

No crank=engine will not go round and round when you turn the key

No start=engine goes round and round when you turn key, but will not run.

[chevybill]

Thanks for the replies,guys.
I am at the no start condition and will probably work on it some this weekend.

Again, thanks.

Does the faulty pick up / magnet call for a distributor replacement?

[95 S_Trucker]

You can replace them separately, but if there is play in the distributor shaft, the entire distributor should be replaced.