I blew an intake tube off the other day, and unplugged the maf so it would run long enough to get home. I put the tube back on, cleared the SES, and forgot about it.

Last night I noticed it was feeling down on power, so I logged a WOT run. I was seeing 5 degrees of timing. No wonder it felt slow! I reloaded my tune, I'm back at 17 now, and everything's back to normal.

Do you guys think it was the MAF code that sent it to low octane table? Did anyone know that our pcm's do this?

 

Yep, the PCM switches to the low octane table when there is a MAF fault. Guys who are tuning in speed density and unplugging the MAF set there low octane table the same as the high octane table to get around this.

 

However, if you just unplug the MAF and not turn the engine on, nothing is reset correct?
Philip S.

 

Gotcha, thanks.

 

Correct.

If you just unplug it to change an intake or something and don't turn the computer on then everything will be fine as long as you plug it back in before turning the key.

 

Yesterday, I was showing off my Airbox mod to someone and forgot to reconnect the MAF. While I was driving home the SES light came on. I got home and reconnected the the cable and haven't driven the truck since. Will this cause my truck to go to a low octane table. I have HPtunning set to 92 octane. What should I do?

 

After a couple driving cycles without the MAF code coming up it should reset back to the high octane table. Either that or reseting the PCM should do the trick.

 

Okidoki, Im gonna go ahead and try to reinstall the tune see if the t works. Thanks XLR8NSS

 

I didn't mean reinstalling the tune. Just meant reseting the PCM like by unplugging the battery or pulling the fuses for it. I don't remember the exact way to reset it but, if you search you can find it.

Just reinstalling the tune won't get rid of the code.

If I misunderstood what you're saying I apologize.

 

If you use good gas all the time, you could just change your low octane table to match your high octane table

The it has no choice