I swear I don't have that tab. MS3 Basic.

 

Hmm, well that didn't work! Don't use that then, go back to your original tune. I don't use a MS2 anymore, but I remember having to mess with filtering when I had one. I don't know all the differences, but MS3 doesn't have a filtering tab as best as I can tell. I suppose the different input hardware negates the need for it, but not 100% on that.

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.

 

 

I'm a big dumbhead...

 

Jeez... I pulled my head out of my *** and here's the file

 

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...

 

Firmware version?

 

MS3 Release 1.2.0 2012228 23:46 GMT

 

Is it possible there is something in play now due to the increase in boost that was in already in the tune that wasn't in play before?

 

are you making more than 11psi of boost?

sounds like youre just simply hitting your boost cut limiter at 6K.

 

Max boost went from 7 to 9 psi, and I'm cracking through 7 at 6000 rpm now.

This is what the Rev Limiter page looks like.

 

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.

 

Yes. Isn't that ~26 psi.

 

no. 180kpa is 11psi.

 

This might help you for future reference; MegaSquirt^® and Turbocharging

 

I set 200 kPa. No change.

 

Given the change in Pat's tune, I turned off Noise Filtering. She rev'ed to ~6800, then did the same thing. I took a composite log.

 

Very nice. Thanks.

 

Is that a composite log of the issue happening? We need a composite log of the rev and shutdown.

 

Is it not? I pulled over, started the log, did the pull to where the dropoff occurs, then pulled over and stopped the log.

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.