Light throttle surging...interesting find...
Thread Starter
TECH Addict
Joined: Feb 2004
Posts: 2,826
Likes: 0
Light throttle surging...interesting find... I was having some issues with light throttle surging (really low TPS), and I think I may have fixed mine. This might not apply to everyone though. What I found was that I was dropping in and out of the main spark tables, so I have been doing some experimenting with the main spark table TPS enable and the main spark table MPH enable. The trick will be finding the right method and settings to change. I tried setting it to enable at 1 MPH, but I found that my ignition timing was higher off throttle because of how the main spark table is set, plus it gave me funny negative trims (go figure...I would have thought more timing meant more fuel). I have also tried .1% TPS, but I saw it switch to the main tables at 0% TPS a few times (I think the problem is I cannot see fractional TPS with HP Tuners). I think the trick will be getting the % TPS and hysteresis right. Just thought I would share.
TECH Regular
Joined: Apr 2003
Posts: 413
Likes: 0
From: Atlanta, GA
I have been watching the same thing, I notice that my spark advance is rapidly jumping 4-8 degrees sometimes +/- when it is surging. I have been smoothing the ramp rates of the spark advance tables and notice a much smoother idle and less surging.
Thread Starter
TECH Addict
Joined: Feb 2004
Posts: 2,826
Likes: 0
If you see that you are jumping in and out of main spark at really light throttle, try setting your TPS enable for main spark to .5 with a hysteresis of .1. I think you will find that your idle fuel is set at the same TPS percent as the main spark enable. You should bring that down to .5 as well.
