2005 Envoy XL 5.3l AFM Valley cover gasket replace?

[Karl Gant]

Hello everyone, looking for some guidance...getting a p0340 code, so was going to take off the intake to get a good look at the cam position sensor. During the evaluation, I was thinking of doing valve cover gaskets, new injector o-rings, oil pressure sending unit, new plug wires, intake manifold gaskets, coolant crossover pipe seals, and the valley cover gasket. I've done the same stuff on a 2003 5.3l Ascender I used to have, but, of course that engine was not AFM and the valley cover was "easy". If I proceed with the '05 valley cover re-gasket, do I need to do anything special because of those solenoids? My local tuner guy already tuned out the AFM, but all the components are still there. I don't want to open a box of "whoops" by messing with that cover, if that is really even a possible out come. Doing this stuff more b/c the vehicle is 18 years old, and we plan on keeping the car. Thanks!

Karl in Arizona

 

[Mooseman]

Hey Karl, welcome!

The P0340 should be fairly easy. The sensor is in the valve timing cover so all that you're planning to do isn't really necessary. However, if you still want to replace the valley cover, you can use #12538832. It blocks off the DOD lifter towers in the valley and eliminates that pesky filter in the oil pressure sensor.

How's your oil pressure? There is also the oil bypass in the oil pan that can bleed off pressure. In both that I did, I had to replace the pump with a high pressure and volume version to overcome it. When I did the full delete in my Saab, I was getting a P0521 because my pressure was lower because I had used the wrong oil pump. That one I used the replacement valley cover. My 08 Avalanche wasn't triggering the code however it just had lower pressure than I was comfortable with. That one I only tuned out the DOD leaving everything in place. I have not heard of anyone just replacing the valley cover leaving the DOD lifters in place. DOD is activated by applying oil pressure to the lifters via those towers so by blocking off them off, it should be OK.

 

[Karl Gant]

Hey Karl, welcome!

The P0340 should be fairly easy. The sensor is in the valve timing cover so all that you're planning to do isn't really necessary. However, if you still want to replace the valley cover, you can use #12538832. It blocks off the DOD lifter towers in the valley and eliminates that pesky filter in the oil pressure sensor.

How's your oil pressure? There is also the oil bypass in the oil pan that can bleed off pressure. In both that I did, I had to replace the pump with a high pressure and volume version to overcome it. When I did the full delete in my Saab, I was getting a P0521 because my pressure was lower because I had used the wrong oil pump. That one I used the replacement valley cover. My 08 Avalanche wasn't triggering the code however it just had lower pressure than I was comfortable with. That one I only tuned out the DOD leaving everything in place. I have not heard of anyone just replacing the valley cover leaving the DOD lifters in place. DOD is activated by applying oil pressure to the lifters via those towers so by blocking off them off, it should be OK.

Thanks Moose...I figured since I'm gonna pull the intake, I might as well do the usual suspects while I'm in there, since we're keeping the car(and I don't know if it was ever done by the prior owner). Eventually, we will do the full-on AFM delete procedure, but for now I was gonna do the extra stuff until I got to it. Was worried about jostling that valley cover with it's extra "stuff". Thanks again!

Karl in Phoenix