I have really bad cam surge below 2000 driving in all gears and I cant seem to get rid of it. Ive tried adding timing to no avail. It only happens under very very slight load. If you barely get on the pedal its fine, but if you back off or take your foot off the car lurches forward like nuts.
What kpa range is this in under extremely slight load? Also should I add more or give it less timing. Ill post my table so everyone has an idea of what timing Im running now...
TriPinTaZ
09-08-2003, 01:40 AM
you need a scan tool to tell you what your KPA range is while surging. However it will be really skewed because of the surging. I fixed mine by setting my closed throttle spark advance to 40 degrees at all times throttle blades are closed.
I have a 260 duration cam so i needed alot of timing. you may not need as much, but if you have not increased this and are using the stock values that may be a big reason. Also once you find the KPA range your cam is in try setting the spark advance tables (400-2000) higher I run32 degrees from 400-1200, 34 degrees at 1600, 36 degrees all teh way to 2000 RPMs.
MY car used to idle in the 30 KPA range. With my large solid roller cam the ca rwould surge so bad it would go from 75 KPA to 100 KPA back and forth during its " trying to idle" After adjsuting the spark on the above tables i mentioned the car finally smoothed out and it idles in the 85 KPA range in gear and 75 KPA in neutral.
Youve got to fix one thing at a time.