MS3 Basic 6000 rpm backfire and check engine light
#22
The fact it made it worse is odd, maybe try less filtering?
Again, I don't know just something to try. I highly agree that logging it via composite logger, which is inside TunerStudio, is the best approach.
#26
I thought I'd recap.
No tuning problems but I need a retune due to changes to the intake piping.
Retune going great, then a backfire at 6000 rpm and check engine light.
Next run up on the dyno produces the same backfire and check engine light.
Tuner reloads the tune I drove in with, and the next run has same backfire and light.
We both assume hardware, like crank/cam position sensor.
Car runs great otherwise.
I replace crank position sensor. No change.
I replace cam position sensor. No change.
Pat's tune moves the drop off down to about 4000 rpm.
We confirm I don't really know what I'm doing.
There's not enough beer...
No tuning problems but I need a retune due to changes to the intake piping.
Retune going great, then a backfire at 6000 rpm and check engine light.
Next run up on the dyno produces the same backfire and check engine light.
Tuner reloads the tune I drove in with, and the next run has same backfire and light.
We both assume hardware, like crank/cam position sensor.
Car runs great otherwise.
I replace crank position sensor. No change.
I replace cam position sensor. No change.
Pat's tune moves the drop off down to about 4000 rpm.
We confirm I don't really know what I'm doing.
There's not enough beer...
#32
Boost Czar
iTrader: (62)
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,688
Total Cats: 4,113
your boost cut is set to 180kPa. Increase that to 200 and see what happens. Since you make boost linearly, the MS might think youre going to pass 180kPa and cut you, makes sense given your rotrex and consistent rpm where it cuts.
#38
This might help you for future reference; MegaSquirt<sup>®</sup> and Turbocharging
#40
The car doesn't completely shut off. It acts like it hits a rev limiter, but the check engine light comes on. The previous composite log was done the same way, but the dropoff occurred at 6000 instead of 6800.