6.0 starting great sometimes and crank no start others

[[email protected]]

Hey there,

I have a 2001 Silverado 6.0 that is giving me fits. I've got through every possibility that I can think of from the fuel pressure to the VATS to the crank sensor. I am just not sure whats up.

Here is what it does. Sometimes it starts, idles, runs great. About every other time, when you first hit the key, it cranks but won't turn over. If you turn it off and crank again, it fires right up. Other times it will fire up, but idle low and stutter.

I get an RPM signal every time. The fuel pressure at the rail is 45 before startup and 50 when idling. Just about everything on the truck is new minus the MAF sensor, throttle body and the fuel pressure regulator. I've done the crank relearn procedure and it doe not seem to make a difference. It seams to get worse in cold weather.

I've attached a scan file where it does a shitty startup and a perfect start consecutively. Any help is appreciated as I'm just banging my head against the wall on this truck.



5-15-22 6.0 silverado fireup.hpl

[MRls.us]

I know I'm probably out of my area of trouble shooting but have you turned off MAF and put it in SD (Speed Density) mode
and bypass MAF?

[[email protected]]

I know I'm probably out of my area of trouble shooting but have you turned off MAF and put it in SD (Speed Density) mode
and bypass MAF?

I have not tried this. Can you explain further? Here is the tune if that helps:

2001 Silverado Tune 6.0.hpt

[MRls.us]

https://youtu.be/BXFSJtimxYM


id watch this theres 3 quick things to do make it sd mode

[[email protected]]

OK,

This VE made a lightbulb go off in my head. It is possible that the tune I used to update this truck from a 4.8 to a 6.0 was for drive by wire throttle and the TB i'm using is drive by cable.

If anyone can help, I am not sure exactly what areas where this might be affecting my tune. Does anyone have a stock tune from a 6.0 with a drive by cable throttle body?