VT 355 supercharged AFM issue

[VL400]

Is that 87% including opening time? If opening time is not included will be close to 100%. It depends what the1 has set the logged PW item as, stock is normally fuel PW not delivered PW.

Still does not account for the spike in commanded Afr.

The inj voltage monitor spike may have been from fuel cut off if it bumped the rev limit.

[Jayme]

you can see in the log when it starts running up to shit. theh MAF HZ drops off suddenly and then the pcm goes to 16:1 commanded and the injector pulse goes to 57%, then the maf hz goes back up, and injector duty cycle spikes back up to 90% rightt after that. I would say its verrrryy close to 100% DC but injector size would not appear to be the main issue, its the flaky MAF reading above 10,000hz which appears to be causing all of the problems.

[delcowizzid]

can you trust any of the airflow data with stock maf tables and a big pipe with a card maf though

[delcowizzid]

i reckon airflow is dropping from fudged maf tables and it hits decel commanding 16:1 LOL

[The1]

Well the MAF tables were done linear upto 512, so far i havn't had issues on cars pushing 270 - 280 G/S

I did a test log on the bench, varying voltage, steady MAF, RPM fuel cut works as intended pretty spot on.

I think first thing to do would be to retest with rpm limit raised.

[delcowizzid]

that should of been stock tables and big maf not fudged tables

[The1]

though the maf scaled fine on my bench.

[delcowizzid]

its all in the setup as soon as you fit a bend before the maf or a pipe weld or obstruction it reads different than the calibration in the tune thats why vs vt vy etc have locating tabs on the pipes and maf so it only goes in one place and rotation onto the airbox lid.and if it had no screen airflow reading can go haywire

[Jayme]

which brings me back to wondering ... is the wonky air flow due to the MAF itself not reading properly due to location/turbulence or is it not reading properly due to the pcm being faulty?

shane - can you take off the air flow meter and start logging the car with tunerpro, then blow acompressed air into the MAF and see if you can get the HZ to read higher?

[The1]

Im more wondering why RPM dropped after 5748RPM it dropped to 5617RPM, Cylair Dropped but MAF is still steady climbing, cylair is based on MAF and Crank pulses, Narrowband o2's are still steady, so something happened causing RPM drop, After which RPM climbed again but then went commanded 16:1, though with the other log the RPM had no issues. Anyway ive sent another bin to Shane using a different MAF airflow scalar, though ive used both in other models without issues.