Cold start fires right up, let it sit for an hour and it will just crank

[Supermoney]

I am stumped. Starting the truck when its 5 degrees outside (F) it fires up immediately.

If we drive it around, get it fully up to temp, etc, come back in an hour or two when its still warm and it will just crank....takes 2-3 tries and then you even need to give it some gas to help it fully start up.

2002 Supercharged, only run 91+
Fuel pump replaced
Fuel filter replaced
New spark plugs / wires
Supercharger fresh rebuild

Anyone have any ideas? Thanks

 

[19963.4lsr5]

I say you have a dripping injector flooding out the engine.


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[MSRP.]

It sounds similar, but you have a lot more going on that I do.
I suspect starter contacts/starter for my 99 (120k miles), where it starts no issues first thing even in -40F, but if I shut it down, and try to start the truck again after a short stop (under an hour), it will struggle to start.
On the hot-start, sometimes it will start even quicker than normal, sometimes it will just crank 2-3x longer before barely coming alive.

If I don't come back to it for a bit more than an hour, it will be just like a cold start.

 

[Sr Auron]

Every vehicle I've had that did that was the ignition control module

 

[suppra87]

[MENTION=86004]Supermoney[/MENTION] Mechanic here, Ive experienced this a few times on LC80's. Check/replace the 2-pin coolant temp sensor for the computer. I think its front and center of the lower intake manifold on the 5vz.

When they go bad they typically tell the engine to run pig rich on a warm/hot start which will flood the motor and just make it crank. You need a much richer fuel mixture on cold starts.

 

[rich dog]

howdy howdy. I had a similar issue with a 98 tacoma. stumped me for the longest time. turned out the efi fuse would get too hot after the engine would warm up. try swapping it with a different fuse. i think its a big square green fuse under the hood. hope this solves it for ya.

 

[suppra87]

 

[19963.4lsr5]

The easiest way to test the ECT is with a live data scanner and with a cold engine the IAT and ECT should be close to each other and within 10 degrees of ambient.


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[Supermoney]

The easiest way to test the ECT is with a live data scanner and with a cold engine the IAT and ECT should be close to each other and within 10 degrees of ambient.


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Thanks I'll do this this weekend, however I wanted to add one more thing.

Found out why filling the gas tank the gas comes to the top within a few seconds and makes filling it up very difficult. Apparently the evap canister is 'plugged not allowing tank to vent properly'.

Would that have any effect on warm starts?

 

[19963.4lsr5]

Thanks I'll do this this weekend, however I wanted to add one more thing.



Found out why filling the gas tank the gas comes to the top within a few seconds and makes filling it up very difficult. Apparently the evap canister is 'plugged not allowing tank to vent properly'.



Would that have any effect on warm starts?

It may be flooding the intake with vapors. But there should or may be a liquid check valve somewhere near the tank in the vent line to prevent liquid gas from getting into the EVAP during tank filling. I only fill on the slowest setting and use the auto stop.


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[enapa]

I say you have a dripping injector flooding out the engine.


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yep.