Why do I have Knock Retard after replacing my PCM?

[Mr. INTENSE]

This can happen if you replace your PCM and fail to have the Crankshaft Position Variation Learn procedure performed. Without having this done, there's no way for the PCM to be synchronized to your engine's crankshaft position sensor, and the PCM has no way to command the exact amount of ignition timing it determines to be appropriate.

For 1998 through 2005 vehicles, you MUST perform the Crankshaft Variation Learn procedure if you physically install a new PCM, replace the crankshaft, camshaft, timing chain, crankshaft position sensor or balancer. For 1997 cars, just swap the Knock Modules and you're all set.

Now that you know you need it, how can you get it done? Just see the following thread:

How Can I Get a CASE Learn Done?

[k0bun]

You need to get a case learn with the install of a new cam? I wasn't aware of this.

[canuck]

Originally Posted by Mr. INTENSE

This can happen if you replace your PCM and fail to have the Crankshaft Position Variation Learn procedure performed. Without having this done, there's no way for the PCM to be synchronized to your engine's crankshaft position sensor, and the PCM has no way to command the exact amount of ignition timing it determines to be appropriate.

For 1998 through 2005 vehicles, you MUST perform the Crankshaft Variation Learn procedure if you physically install a new PCM, replace the crankshaft, camshaft, timing chain, crankshaft position sensor or balancer. For 1997 cars, just swap the Knock Modules and you're all set.

Now that you know you need it, how can you get it done? Just see the following thread:

http://www.3800tech.com/forum/showthread.php?t=3

The thread does not work. Can you assist?

[Mr. INTENSE]

Above link is now fixed.

Sorry about that!

[NickT'sGTP]

I've never had it done after all of my mods....Is that bad?

[Quick6]

Don't feel bad, neither have I 3 Cams later

[NickT'sGTP]

I'm getting it done tommorrow. Hopefully I will notice the difference....Also....is there such a thing as resetting the pcm? I heard If you take off the negative battery terminal and press on the brake. It will relearn the TPS curve and a bunch of other stuff....is this true or BS?

[FreemenGMTech]

little known things that gain you big differences...

thanks for enlightening them Scott... hey this is easy i can replace all this myself... why doesn't your product work right????

[NickT'sGTP]

CASE relearn is done......All I've noticed is that it doesn't hesitate as bed when I accelerate, and it doesn't have as rough an idle as it use to. Spark advance, when they had it hooked up to the snap-on scanner, jumped to 36* when they reved it up. When I got it scanned at the track I think the max we saw was around 22-24*. Might of been more....But I definitely noticed a difference after the CASE relearn. Only cost $26.00.

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