EVO IX
26,000
Injen hard pipe intake W/ K&N AF
Perrin turbo back exh (test pipe)
stock map
stock O2's
looks stock otherwise

act's sort of like it's in fail safe, won't rev over 1500 on accel and will go to 4,000 if you blip the throttle in nuetral but then drops back to 1500 if you hold it WOT (in nuetral). Sounds just like a rev limit bounce but at 1500.

customer says it happened suddenly just driving on freeway.

no MFI codes (readiness tests not complete?)
all data list looks normal, O2's, short and long fuel trim, MAP, VAF, inj, timing, TPS

coils firing ok (timing light), injectors seem to be clicking ok, cam timing ok,

plugs very sooty rich, cleaned, no difference.

fuel sample ok, fuel pressure ok

pulled the BOV and capped BOV holes, no difference.

 

Sounds like the MAF came unplugged or there is an intercooler pipe that came off.

Good luck scoping the problem

 

Yeah, Mitsu calls a MAF a VAF, and the readings looked normal. When the BOV was off you could feel pressure build. There's no boost gauge, maybe should hook one up.

 

Hmm pull off the intake and take a look at the MAF see if that screen got sucked in and is scewing out the airflow readings.

 

screen looks okay, the MAF data list readings are exactly as the SM calls for

 

When the MAF is disconnected seems to run a little better, like it's in a failsafe with a 2800 rpm limit and it doesn't stutter to get there.

starting to think bad ECU also, pulled it and the board looks okay, no burn spots

 

time for speed density?

could be a few problems, i think u have highlighted most. recheck ur fuses and electrical grounding.

a local evo VII had a similar problem, the car would not rev part 3000rpm. this was due to bad gas.

 

did you reset the ecu? (disconnect the battery)

 

yeah, checked fuses and grounds- all okay, pumped a qt of gas at the return, very clean.

I would do speed density if I could but Mitsu might not buy it

tried ECU reset, no difference

 

feeling sort of silly

it was the intercooler ducting hose came loose at the intercooler inlet. The only connection you couldn't see without moving the splash shield. There was 2 of us working on it, that's my excuse.

 

damn i hope thats my issue. after doing a few log pulls i got a loud pop noise thought it was fuel/boost cut. then the car runs like car had to do like 10 mph home. AFR all over the place and cant rev the car and while im moving if i try to give gas its like i hit a brick wall and car almost wants to die.

 

^ sounds like you popped an ic pipe...if not check the hose for the fpr...might have came off the intake manifold...causing weird afr's