2008 Escalade intermittent crank no start

[Ncsujrc]

This has been going on for a couple of months now... if we drive it for 1-4 hours intermittently it will turn the engine off when coming to a stop. It doesn’t sputter, it just dies and will not restart until about 1-1.5 hours have passed. It will always restart after that period of time. And I have not touched a single thing. First time, I towed it to a dealership- they would not even test drive it to duplicate the complaint so they couldn’t see anything wrong with it- they kept it 3-4 days and i had to ask them to replace SOMETHING. So they programmed and installed the fuel pump computer, it died a couple days later. I then ordered and installed a new acdelco fuel pump, died again. I installed a acdelco crank sensor and relearned it- died again. I replaced the mass air flow sensor ( no programming needed that I know of)
It has 60 psi fuel pressure and spark when this event occurs. I have removed the engine ecm and tapped it and tried to cool it off- but it still will crank and no start. I have swapped relays in the fuse/ relay center for the ignition and start run circuits while it is messing up- no change. What else am I missing? The only thing I have not done is I haven’t had my noid light to check power to injectors when this event occurs. PLEASE HELP!!

 

[Foggy]

You've really covered a lot. My guess was going to be crank sensor.. When
they are going bad, sometimes they just stop working when hot.. then cool off
and work again.. Maybe a bad one ?????
Cam sensor "could" do the same I suppose, but maybe someone will chime in
on the cam sensor
Is your charging system "good" and have you load tested your battery
when HOT ?? Just spit balling here

 

[OR VietVet]

Welcome to the forum from Oregon.

You have replaced a lot of things with no help. When you do a crank and no start you need to be checking, at the same time, for spark and fuel pressure then. I could give two ***** what it has when it is running. What color is the spark? Blue=good, orange=bad.

 

[thompsoj22]

Ignition switch, inexpensive guess. should not be temperature sensitive, but no power/intermittent power in the run position would duplicate your issue. I personally have never experienced vapor lock but the fuel rail supposedly gets hot enough to make it happen, bleed the shrader on the rail with a rag next time and see if it affects it. Use a rag and dont burn the car and yourself to a crisp, next roadtrip remove the plastic top engine cowl and see if it still does it. It does sound electrical to me, no codes = power interuption, just guessing, but that has got to be frustrating and must be fixed. hang in there! do the ign switch to eliminate it.

edit, just read the post again, if it has spark/fuel pressure it should at least pop/stumble, a complete no start while cranking with spark/fuel would be hard to do? cam position sensor imo would simply create rough idle/poor performance and should throw a code if you want to rule it out start the car cold to prove it runs, shut it off and disconnect the cam position sensor and see what happens. If this is the 6.2 it can be done, you can see the connector behind the metal bracket, simply lift the clip with a small screwdriver and pull the connector off and try to start. id like to know what happens? i say it still starts?

 

[Ncsujrc]

You've really covered a lot. My guess was going to be crank sensor.. When
they are going bad, sometimes they just stop working when hot.. then cool off
and work again.. Maybe a bad one ?????
Cam sensor "could" do the same I suppose, but maybe someone will chime in
on the cam sensor
Is your charging system "good" and have you load tested your battery
when HOT ?? Just spit balling here

It is a new battery with clean connections, although I have not tested it when the problem occurs- mainly because it spins over quick, it just won’t start and it has 12.5 volts while hot and condition occurring ( thank you for the help- just adding all information i can think of to assist with diagnosis)

 

[OR VietVet]

Justin, thankfully you were detailed enough with your initial post to indicate that the engine spins but will not "fire off" when the problem occurs. Again, I am still of the opinion that you need to test for what you DON'T have when the problem occurs.

 

[thompsoj22]

next time it does it tweak the harness on the gas pedal position sender, no change? pull the duct at the throttle body and while someone cranks gently push on the top of the plate and open it slightly, no change? walk to a chili's and order a tall ice cold 20 0z. beer and wait the 1.5 hours in comfort!

 

[Doubeleive]

stop throwing money at it and spend $300 for a clone tech2 off of ebay or china-car-diags, then give yourself a internet 101 crash course on how the tech2 operates and hook it up, re-create your no-start issue and run the tech2 diagnostics that should pin-point your issue. until you know for sure what the problem is your just guessing and spending more money than you need to.
you can also purchase the gm service manual on .pdf off of ebay there like $25-30 that will help you in certain situations where you need to know things like specific voltages and diameters that may be related to your no-start issue.

 

[OR VietVet]

Or, also sign up to ALLDATAdiy.com for a year of info and specs and testing procedures. Wes is correct, I hate throwing parts at something. Get that Tech 2 and do yourself a favor.

 

[Ncsujrc]

Ok, tonight without getting it to act up; I unplugged the camshaft sensor and tried to start it, and it started and ran. I plugged it back in and unplugged the throttle body- it started and ran. The only thing left I can think of is the engine ecm