I don't know if this is correct or not, but my timing doesn't stay smooth, it kinda jumps a bit each way. When I graph either of the "spart advance" options in TunerRT, it looks more like a live heartbeat then a dead person heartbeat!

Also, when the car warms up to over 195 degrees the timing comes up and get a little more steady, but still doesn' stay on one value. I may jump from 9.5 to 10.5 and down to 8.5?

I would think this isn't normal and that the timing according to the computer should be dead on steady. Someone please clue me in to what it's supposed to be like. I'm trying to find a sluggish power problem and I'd rather get this dizzy out of the way.

I'll post another for my sluggish problem.

Thanks!
-dperk

 

There are a few different things that go into the ECM's timing calculation, and some of them can cause what you're seeing. Make sure you're not getting any knock retard, and make sure idle over/underspeed timing correction is disabled. Those two in particular will make the timing seem twitchy.

A slightly unstable idle can also cause it, because the changes in RPM will cause the ECM to look up it's base timing value from different cells in the table.


On a stock cal, it's fairly normal. The ECM will adjust the timing a few degrees either way to try to compensate for small changes in idle speed, that are too small for the IAC to correct.

 

hmmm, Ok. I haven't checked the idle underspeed/overspeed. I don't have a VSS yet, so that is probably important. Is that a constant?


I am only getting knock counts up to 4 knocks, and that is at start up.


I did notice that my IAC is reading 0 steps at idle. Should it read anything else when at idle?