2005 Tahoe Ls stalling

[Bacon83]

Truck has about 280k on it. From a cold start it will run and drive for 20 minutes then stalls and won't restart. I've already changed the crank, cam, map, mass air, oil, and coolant sensors. Along with the fuel pump, fuel relay, ignition relay, and the ecm. Plus cleaned the throttle body. The truck has no check engine lights on. And at this point I'm completely lost. When it dies I have 54 psi at the rails. Throttle body is at 4% at idle and opens to 14% after it dies. Also showing pluse width on the injector. Any ideas please comment.

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[OR VietVet]

Welcome to the forum from Oregon.

I am assuming that when you say it will not start that you mean it cranks and will not start/fire off.

You said that you have 54 psi, at the rails, when dies. Do you have spark at that same time?

 

[Bacon83]

Honestly that's the one tool I dont have to be able to test the spark. So I don't know if it is the spark that is cutting out

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[Bacon83]

And correct when it dies it will crank but not start until about an hour later and will run for less time then from a cold start

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[PNWYukon]

Whoa, that sounds like you dropped a nuclear parts bomb on that rig. You really need to have live data during these episodes to know what is actually happening to your Tahoe. From your description it seems money is not an issue, so buy yourself a really nice scan tool and solve the issue. Replacing all the parts might be a good refresher for our older Tahoes, but you also might be chasing it for a long time without the live data or proper scan tool to talk to your Tahoe.

 

[Bacon83]

I'm using a snapon Apolo d8 and watching the live data. Nothing seems abnormal. When it dies it shuts down like I turned off the key except everything stays on bit the engine. I'm not normally one to throw parts at a car but I have no where to start from. So I started with the common issues and tried process of elimination.

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[Bacon83]

I have a good running twin to this truck so I've been able to swap parts and not spend the money. I've only been buying the parts I know are bad

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[PNWYukon]

There has to be something the ECM is doing or seeing to make this happen. Does your scanner have Mode 6 Data? Fuel trims? I don't know how in depth your scanner is, but your should be able to monitor electrical live data as well, if this is not a fuel issue.

 

[PNWYukon]

From quickly looking at that snapon tool's specs it said it has bi-directional communications. Try talking to each module possible and and monitoring any data live or stored that they give you.

 

[Bacon83]

Basically the only thing my scanner doesn't do is graphing and reprogramming. I am able to see fuel trim. Off hand I can't give you the numbers. I'm headed into work and can't get back to it until tomorrow. I can tell you I do have random misfires but it doesn't seem to be shutting down because of that

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[Cbncanada]

It sounds like you have an electronic part that is heating up and shutting off the engine. Once it cools enough the engine restarts but for shorter time makes sense as the part will not take as long to reheat. Not sure which part it is but sound electrical to me.

 

[OR VietVet]

That was a big problem with the old ignition modules.

 

[Bacon83]

Lol. That's the way I'm leaning. But I don't know what else is left

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[Bacon83]

From what I can find there is no ignition module on these. It was moved into the ecm

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[OR VietVet]

From what I can find there is no ignition module on these. It was moved into the ecm

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Yea, I know that. I was just saying your symptom is just like that problem with the modules.

 

[TollKeeper]

With everything he has replaced, I am not sure there is much left that a "heatsoak" would cause errors with. The one exception would be a vaporlock in the fuel rail, and I cant remember if the 2005 models were return, or returnless fuel systems. I know there was a change right in those model years.

If he had a older truck, than I would suggest fuel injectors since the older trucks run in batch fire.. or the older ignition modules (like previously mentioned). But neither of these are relavant here..

Unless the ECM has a crack in the board, and heat soak is causing it to spread apart.. But even thats a stretch.

 

[Bacon83]

I just replaced the ecm today

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[S33k3r]

Unless the ECM has a crack in the board, and heat soak is causing it to spread apart.. But even thats a stretch.

I see what you did there...

 

[OR VietVet]

Crack it or stretch it, probably not good either way.

 

[Matthew Jeschke]

Honestly that's the one tool I dont have to be able to test the spark. So I don't know if it is the spark that is cutting out

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For a few bucks you can get a tool to test spark at the parts store. It goes inline with spark plug wire.

Most all of these parts have a diagnostic procedure so you dont have to guess if they are working or not.

Do you have a fuel pressure tester? what about your fuel pressure regulator? Maybe it is defective and cutting off fuel somehow?

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