Grand Cherokee ignition timing

Ignition timing on cylinder 1 at idle is bouncing around 9 degrees and while driving when I leave a from a stop just touching the throttle it jumps up too 36 or 38 degrees and comes down in degrees the faster I go. That doesn't seem right too me. I would of thought it would start around 9 and go up in degrees the faster you go. I have the 4.0 liter in the grand Cherokee. If the timing isn't working right what should I look at first?

Hey Jasondo! I've been looking at some of my old captures, and I'm not sure that you're necessarily looking at a problem. To be honest, I don't look at spark advance all that much on most vehicles, except on some cases of low power. Is there a specific symptom you're experiencing? Or are you just concerned about the spark advance by itself?

What year is your Jeep? For comparison, this is a capture I took off an '02 Grand Cherokee, no issues. There's a couple times where the spark advance goes up to around 30 degrees on initial throttle application.

www.scanshare.io/share/Iynbp_Qx8EKduuTRHGeVIA



Since the MAP and TPS are the primary load inputs on this engine, they're the ones that the PCM will look at for spark timing. For comparision, I also looked at a 4.7L from a 2000 Grand Cherokee, and it has the same kind of spark advance behavior.

www.scanshare.io/share/Jf4XS3bVRk2RD71Ij3K2cw