411 swap cmp -40*

[9851Chevy]

Hi,

I have a 98 Tahoe 5.7 with a 411 pcm and just got my V1 commercial so I did a relearn and everything is running fine. When I checked the CMP retard(vortec) it read avg -40.75.

I tried to adjust it by moving the dist. one tooth forward and then it read between -80 and -50. Then I tried the reverse direction and was able to get -35, so I moved it back one tooth and tried again and it wouldn't start at all. I ran out of time so I just put it back where I started at -40. It starts fine and doesn't throw a code, so is the scan tool reading incorrectly? Or is it really -40 off and I just need to try again?

Maybe I'm using the wrong PID but I didn't see any others that seemed correct.

[Taz]

Hello 9851Chevy,

Have a look at this thread regarding Camshaft Position Retard …

http://forum.efilive.com/showthread.php?14762-Camshaft-Position-Retard.

I believe zero (+/- 2 degrees) is the required tolerance ...


Regards,
Taz

[9851Chevy]

If I move the distributor closer to 0, it won't start at all just back fires. That is why I am wondering if the displayed value is incorrect or if something else is wrong.

[Taz]

I rarely work with the Gen I based Vortec engines. I was merely trying to point you in the right direction. You may want to send a PM (private message) to Forum member “ZR2_350” who started the thread linked in post #2 above. He finally got his camshaft position properly oriented, and appears the engine ran well afterward.


Regards,
Taz