New here with my new 07...problem?

[NJ Denali]

and it continues...
pan dropped and oil pump replaced per GM.
Bearings and crank inspected and all appear as new. All tolerances within spec. Everything reassembled and waiting for startup Monday am. One hint of noise and I'm looking for a new engine. I'm not sure what else to do here.

 

[NJ Denali]

Finally got her back today. New lifters, new oil pump and none of it worked. They followed GM's instructions to the letter. Yesterday they did a simple fuel induction service and that did the trick. There was carbon build up on top of the pistons that caused the knocking. I've read about that (among 10 other things) related to the fix and that did the trick. I still don't understand it, but that did the trick. The GM regional doubled my extended warranty to 6 years or 72,000 miles to thank me for being patient. That's the kind of stuff that will will bring me back to GM. Acknowledge the problem, and fix it.

 

[chris12]

Off topic, but how much did you pay? I'm looking at a '07 denali with low mileage now..

 

[ProStreetCamaro]

Finally got her back today. New lifters, new oil pump and none of it worked. They followed GM's instructions to the letter. Yesterday they did a simple fuel induction service and that did the trick. There was carbon build up on top of the pistons that caused the knocking. I've read about that (among 10 other things) related to the fix and that did the trick. I still don't understand it, but that did the trick. The GM regional doubled my extended warranty to 6 years or 72,000 miles to thank me for being patient. That's the kind of stuff that will will bring me back to GM. Acknowledge the problem, and fix it.

Glad they got it figured out for you. Makes me wonder what kind of cheap junk fuel the previous owner used. If I were you I would run a bottle of redline SI-1 fuel system cleaner through it every 10K. That will prevent it from happening again.

 

[NJ Denali]

Off topic, but how much did you pay? I'm looking at a '07 denali with low mileage now..

$31,900...and it may be the biggest waste of money ever.

Glad they got it figured out for you. Makes me wonder what kind of cheap junk fuel the previous owner used. If I were you I would run a bottle of redline SI-1 fuel system cleaner through it every 10K. That will prevent it from happening again.

I spoke too soon. It's back after a week. And nowfor the second time in two weeks, it will not start. It wont turn over; not a click. There's full power at the battery even load tested.

I'm starting to get pissed.

 

[ProStreetCamaro]

Man Jeff I am sorry to hear that. Starting to make me wonder why somebody got rid of such a nice low mileage SUV and you might be finding that reason out right now. The starter issue should be fairly easy for them to figure out. All they have to do is start checking power at the starter then work there way back through the starter electrical system till they find the guilty culprit.

As for the lite engine knock under load we know its nothing major because the bearings and oil pump are good. This leads me to think you are getting some lite spark knock. These engines are known to have knock sensors that go bad and if yours are sending false signals to the computer it is very possible that is what is causing the knock. When they cleaned up the little bit of carbon in the chambers it was enough to stop the spark knock and once the carbon started to build up again it came back and the computer is not pulling enough timing to stop it.



Just thinking out loud here.


EDIT: What octane fuel are you running?

 

[NJ Denali]

I'm running 91, but this isn't that kind of knock. After all I've read I'd liken it more to CSK.

 

[ProStreetCamaro]

I'm running 91, but this isn't that kind of knock. After all I've read I'd liken it more to CSK.

CSK? Carbon spark knock? To be honest I really do find that hard to believe would be the case because these LSX engines are not known to carbon up very easily and yours has such low miles I just cant imagine that would be the case. Try running 93 if you have it in NJ and see what happens. If I am not mistaken the 6.2 in the Denali's call for premium which in most areas is 93. Some sunoco stations sell 94. The 6.2 has high compression and really does need the 93. My 99 SS Camaro LS1 would knock and ping if I didnt run 93 in it.