Hello,

What is an acceptable amount of variance in the rpm signal when viewing a log file? I'm seeing fluctuations in my rpm signal as it climbs through the gear. It is consistent regardless of the gear. THe variance is sometimes as high as 400 rpm. I have my box wired directly to the battery and the connetions are soldered. My ck sensor harness isn't next to any high current items or the alternator. Any help would be greatly appreciated. Thanks.

P.S. I had my box wired to a distribution post and a sheetmetal ground before and the noise was terrific!!! Re-wiring it made it a million times better, but it still isn't right. I've even looked at another buddies log and he is only seeing little spikes (maybe 30-40 rpm)....

 

On my last log I had rpm spikes in the 20-90 range.

Rob

 

Thanks Rob

 

make sure that you graound the crank and cam sensor shields.

 

They are both grounded at the front of the head. The more I think about it, I should just borrow a Fluke scope from work and look at the ground and the ck signal. Obviously should be noisy so I can try different things and re-check. My only worry is if I have to load the car to get the problem to show up. I have't tried doing a datalog at idle/cruising around so I don't know if it is only under load or not. If it is, I guess I could do a recording and try to load it on the street. Hate doing that as the car hooks for shit on the street. Anyone else try watching some of their signals with a scope? My only experience has been OEM stuff---should be the same I would imagine....