Hey guys, I was wondering if anyone has had this problem happen to them, or knows what to do?

Problem:
Every time under hard acceleration the car builds boost (later than usual) and holds it at23(ish) PSI all the way up, however over the course of every thousand RPMs the car seems too bog (not backfire). For example, in second gear when I floor it the car builds boost and at 3K it starts going (like usual) but at around like 4K the car loses all the power then the power is back on around 4.5K. The weird thing about it is that my boost gauge reads 23 psi the entire time. The car shakes a lot under heavy acceleration. I took the car to AutoZone to get my error codes read, and the only one that came up was the one for not have a cat.

Modifications:
-Helix TBE (catless)
-Walbro 255
-Apex'i Intake
-Xede (V.2)

I have read other people with similar problems, stating that it was some sort of vacuum line leak or an issue regarding the fuel pump. I have checked all the intercooler hoses and all appear to be fine. I have only checked the top connections of the fuel pump and made sure those were good. Tomorrow I am going to take the entire pump out and check the filter.

Thanks for your help
-Gonzalo

PS: I am hoping to get this problem fixed by thursday. Since, my family and I are evacuating to Dallas due to Hurricane Rita. And I really don't want to leave the Evo behind.

 

is your map tuned for your intake? Are you running a vta bov?

 

No, its not tuned. I was planning on getting it tuned Nov. 5 when vishnu is coming down to Texas. However, I have been running without a tune and with the intake for over 3 months and I haven't had any problems.

 

Are you using the stock fuel pump or aftermarket?
If you still have the stock pump change it.

 

A friend of mine, mentioned checking/changing spark plugs ?!? Could this help?

 

I just finished changing out the spark plugs. Somehow this made the problem a lot worse or created a whole new problem. After installing them (NGK BPR7ES) and checking the gap the car turned on but backfired 2 times. The idle was extreme rough (sounded almost like I had a pair of HKS 280 cams). I quickly turned it off and rechecked everything. turned it back on, same problem. Does anyone know what might have gone wrong?

 

What octane are you running with 23psi?

What are the plugs gapped to?
Too much fuel maybe?
MAF gone bad?
Tune for the intake!!!

 

EVOONYOASS:
-I am running 93 oct.
-They are gapped to .27

I am leaving tonight and taking my dad's car up to Dallas, hopefully when I come back I will be able to figure this out. For the meantime the car will be staying in my garage.

 

are you sure this isn't a clutch issue? any slippage going on here?

 

.027, right? Im sure thats what you meant.
That issue aside, it doesnt sound like spark blow out.
Though a visual inspection of the couplers is fine if one is blown off, Id do a true boost leak check, but again... if the gage is reading 23psi, chances are that isnt the problem either... Im leaning towards the ecu pulling timing, wether its true knock or phantom, your guess is as good as mine...

 

You should also post in the Vishnu forum too. Or even better call Vishnu and talk to Dustin or Shiv, see what they say.

 

ive had bad ngks out of the box....
that will make you sh.. your pants

last car though, not evo same style of plugs though(different model)
the car was fine until about 3500 rpm