2008 tahoe 5.3l in need of desperate help

[petethepug]

Wait, did the technician do an AFM delete and replace the valley cover with a non AFM valley cover?

 

[Nickct203]

Here's a quick update, I ran by my buddy's house just to give an extra pair of eyes and hands. I realized that the dod/afm delete kit did not come with the new valley cover. So I'm gonna guess and hope that's the problem cause that is a simple and easy fix. I will be getting the new valley cover tomorrow and we will see if that does it.

 

[Nickct203]

Wait, did the technician do an AFM delete and replace the valley cover with a non AFM valley cover?

Haha just posted right before I saw this. No he used the same afm valley cover cause the kit didn't come with one so he didn't know

 

[petethepug]

I posted with a question because I can not remember if the DOD delete uses the existing valley cover or the non AFM. Someone will chime in to verify which one must be used.

At least one person has done it the wrong way and posted the results.

 

[Nickct203]

I posted with a question because I can not remember if the DOD delete uses the existing valley cover or the non AFM. Someone will chime in to verify which one must be used.

At least one person has done it the wrong way and posted the results.

From what I read after seeing he used the stock afm valley cover it is the wrong one. Again good chance I'm wrong, but that's where the more experienced people come in

 

[j91z28d1]

huh.. that's an interesting one. let us know if it fixes it.

 

[kbuskill]

I can't see why having an AFM valley cover would have any effect on how it runs. Once it is turned off in the tune the ECM and engine couldn't care less what type of valley cover it has.

If this were the problem then everyone who turns AFM off in their tune would have to replace the valley cover and that is simply not the case.

Now, unplugging the VLOM without turning it off in the tune will definitely cause misfires.

 

[j91z28d1]

I can't see why having an AFM valley cover would have any effect on how it runs. Once it is turned off in the tune the ECM and engine couldn't care less what type of valley cover it has.

If this were the problem then everyone who turns AFM off in their tune would have to replace the valley cover and that is simply not the case.

Now, unplugging the VLOM without turning it off in the tune will definitely cause misfires.

in theory, it seems possible. I believe the lifters are fed oil from the back of the block, so the front 2 would be the last to get oil. if enough oil is getting past the lifter bore, up into the afm oil channels, by the time it hit the front, might not be enough to pump them up?

I think in theory, it's possible. but I'm not sure it would.

 

[kbuskill]

in theory, it seems possible. I believe the lifters are fed oil from the back of the block, so the front 2 would be the last to get oil. if enough oil is getting past the lifter bore, up into the afm oil channels, by the time it hit the front, might not be enough to pump them up?

I think in theory, it's possible. but I'm not sure it would.

If the seals that go on top of the towers were leaking then you would have issues for sure.

 

[Nickct203]

At my buddy's now, the dod kit has a module that plugs into the obd port. It runs a little better when it's plugged in but still sounds and run rough as hell. The misfire codes went away but now it has a p1600. I'm about to give up on this truck.