Erratic MAF readings on DS

[Dean]

Looking through some DS files from last weekend, I see erratic readings from the MAF (highs & lows) with no corresponding reading from other sensors, like O2, RMP, & TPS.

Example: 12.22 run, top of second, MAF @ ~400 (Extender Chip)
- Next frame (6.1fps), right at the start of the 2-3 shift, the MAF spikes to ~510
- Next frames, ~380, ~370, ~350, during 2-3 shift & RPMs drop ~500
- Next frame, MAF dumps to ~40
- Next frame, ~360
- Next frame, ~40 again
- Next frame, ~360 and it appears “normal ‘till near the end where it spikes to ~510 @ ~100mph, and then 14 frames later it dumps to ~40.

I saw a similar “dump” reading on the previous 12.24 run, but just once a few frames before the 2-3 shift. No spikes. On a the previous 12.39 run, there were no dumps, but multiple spikes @ 39, 66, 102, 107, & 109mph. No popping on any of the runs, 0.0KR, O2s in the 770-790 range.

I'm wondering where to look, and I'm thinking the 3" itself.

 

[Dean]

Snapshot of the file:

http://home.pacbell.net/sfnelson/12-22_113mph.jpg


:-Dean

 

[Dean]

I was directed to this:

http://www.thrashercharged.com/chips_htm/cal_hints.shtm#16

 

[TurboBob]

This is typical of MAF dropout. You will see it affect the MAF trace but will not see it affext LV8, injector pulsewidth, or timing.

The extender chips Anti-dropout software prevents these dropouts from affecting the fuel or spark delivery, but they will still show up sometimes on DS.

It's no big deal. Your MAF is fine.

Bob

 

[Dean]

Dang you are smart. Thanks for putting that in the chip!

:-Dean