2007 Yukon Denali Intermittent Crank No Start

[Doubeleive]

No, I never cleaned the throttle body. Has 220k miles on it. Should I clean or replace? Whats the goal with cleaning and could it cause a crank but no start condition?

definitely clean it....and the maf and a new air filter

 

[rdezs]

are we confusing cam with crank sensor? he replaced cam sensor but these will run without a cam sensor. they won't run without a crank sensor?

I'm a bit lost lol

Aftermarket camshaft position sensors are notorious for a crank no start symptom, with no codes thrown. The last time I run into that was with a Wells brand. Tech 2 said it was getting the signal.... Swapped it out for an oem ACDelco, and it fired right up. Personally, I would look no further until I replaced the camshaft position sensor with an oem unit followed by a CASE relearn.

 

[donjetman]

no need for CASE relearn after a CAM position sensor change. I changed mine last summer.

 

[rdezs]

It will run forever without doing the relearn.... But it just won't be as efficient as it's capable of without it

 

[donjetman]

It will run forever without doing the relearn.... But it just won't be as efficient as it's capable of without it

my Yukons efficiency/mpg stayed good without a relearn.

 

[rdezs]

The mpg is probably a pretty good indicator that it's right on.

I was thinking it's a lot like when I was working on my first small block Chevy, setting the point gap and the dwell. It would fire up and run okay. Put a dwell meter on it, and realize I only got it close.... Was off maybe 10° on the dwell. Just like setting the distributor to get the engine to fire up. Always follow up with a timing light to get it perfect. There's nothing better than absolutely knowing it's on the money. (Sort of like checking the push rod length)

But yeah, if fuel mileage is staying the same, that's probably the best measurement overall

 

[Maxpower_454]

It was an oem camshaft sensor. Thars not the issue.

No info on grounds?

 

[rdezs]

The important ground is where your negative battery cable goes down to just above the oil pan on the driver side. Don't just clean and reattach.... Check the resistance of the negative cable to make sure it's serviceable. Then the ground strap from the back of the engine up to the firewall. Depending on the year, you'll probably find another ring connector where the battery cable attaches to the block. Normally that is routed to near the front of the frame rail on the driver's side. Don't forget to also check the resistance of the positive battery cable.