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View Full Version : S15 SR20 problem


soulsynchromachine
02-13-2009, 05:47 PM
I just resently did this swap, motor was square decked head resurfaced, crank turned and polished, new bearing arp bolts apexi head gasket, and ssqv with front mount.

It runs good until you get on it. It will pull (kinda hard) then at 5k it will pull even harder :loco:. And then it will also backfire. It has stock injectors and turbo, just hks hi power exhaust. Any ideas?

rioredstang
02-13-2009, 06:13 PM
I don't know a lot about turbo's but backfiring at high rpm sounds like a lean condition. You need to get someone to hook up a scanner and what O2 sensor and see if its leaning out. You also need to watch map voltage. Backfiring will kill map sensors. Its a good start but need more info to tell much more.

soulsynchromachine
02-13-2009, 06:18 PM
Right now i have the stock o2 sensor in it now. When i hooked up the scaner it threw no codes. It wont anly backfire at high rpms. It will backfire when i shift at 2500 or 3k.

wrxn240
02-13-2009, 06:38 PM
Do you have a boost guage? Does it feel like it's just building more boost? These problems seem quite normal and might not even be considered problems...

WoolyS14DET
02-13-2009, 06:47 PM
Are you sure you cam timming is correct and it didn't jump a tooth ??
Also are you sure that your CAS is installed correctly ??
Hook a timming light up to it and see what is at.

soulsynchromachine
02-13-2009, 07:05 PM
Well i have some crappy boost guage, Greddy in transit awaitin it, But the gauge will read fine. I think the timing is right. I hooked up timing light and it was perfect at about 16-17 degrees. It feels as though it should pull all the way through as it pulls at 5k. i also have some compressor surge. Even not under boost.

fliprayzin240sx
02-13-2009, 07:43 PM
How much boost you running? Also, what fuel pump and sparkplugs?

soulsynchromachine
02-13-2009, 07:54 PM
Ngk spark plugs and a walbro 255. Boost is running at bout 7 psi.