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01-22-2004, 05:06 AM | #1 |
Scooby Specialist
Member#: 32118
Join Date: Jan 2003
Location: Houston, TX
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Crazy AFR's
I was out with a couple of high-rollin' domestics tonight playing around because I just poured in some C16 for some fun. I ended up running a LS1 Formula Firebird on slicks in the back, skinnies up front, no exhaust, race gas and a decent shot of gas. We went from a 20 punch and I ended up putting about 2-3 on him.. I have a vid I'll link soon, but that isn't the point of the post. Well about end of 3rd gear, my motor pops and detonates.
So I pull into the gas station and check everything.. seems okay. I change maps to a more conversative one. I go for a test run. 50 punch, 3rd gear. The turbo screams, and the exhaust is deafening.. but I'm not going anywhere. I look at the boost gauge, 1.7bar. ***?! I look down at the wideband.. 16.1:1 AFR!!! I let off. I turn down the boost. Stand on it. Same thing. 16:1. I turn off the boost controller and switch my map to my pump gas map.. which is EXTREMELY conversative especially on C16, then I floor it. 15.5:1. Something's wrong. The car kept buckin' and popping and hesitating. No bueno. Even at wastegate boost (about 12-13psi, it's my secret sauce wastegate ), the AFR's would jump straight to 15:1-16:1 on my wideband. I know it's the wideband because at cruise and partial throttle everything seems normal. This leads me to believe that my front air/fuel 02 sensor went out on me. Probably clogged up from all that lead. What do you guys think?
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01-22-2004, 06:59 AM | #2 |
Scooby Newbie
Member#: 9976
Join Date: Sep 2001
Location: Atlanta, GA
Vehicle:2003 Subaru WRX Blue |
Could be any number of things. Is it running right in closed loop, with your wideband displaying around 14.2? I would check the maf sensor first. Then check the fuel pressure. The front O2 sensor should not impact full throttle mixtures as the system is in open loop. The only way it might do that is by using long term fuel trim offset. I haven't seen any evidence of that happening in my experimentation.
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01-22-2004, 09:26 AM | #3 |
Moderator Member#: 922
Join Date: Feb 2000
Chapter/Region:
MWSOC
Location: Schaumburg, IL
Vehicle:16 WRX (white) 04 FXT (red) |
What year is your car?
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01-22-2004, 10:02 AM | #4 |
Scooby Specialist
Member#: 5994
Join Date: Apr 2001
Location: Fort Collins, CO
Vehicle:2004 Impreza WRX STi Java Black |
Check your vacuum line running to your FPR.
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01-22-2004, 10:07 AM | #5 |
Scooby Specialist
Member#: 32118
Join Date: Jan 2003
Location: Houston, TX
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My car is a 2003. I'll check that out.
Well *** do you know. Sure enough, it came off. How did you know? |
01-22-2004, 10:12 AM | #6 |
Scooby Specialist
Member#: 26568
Join Date: Oct 2002
Chapter/Region:
NESIC
Location: Brighton, Mass
Vehicle:2003 Yellow Bugeye Version 8-Vf37 |
FRP is located on the passenger side of the manifold right? I put a small clamp on mine because it was the spot i use to run my boost guage off.
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01-22-2004, 10:47 AM | #7 | |
Scooby Guru
Member#: 8512
Join Date: Jul 2001
Chapter/Region:
South East
Location: St. Pete, FL
Vehicle:2002 WRX chassis... stage-infinity.com |
Quote:
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01-22-2004, 11:24 AM | #8 |
Scooby Newbie
Member#: 13461
Join Date: Dec 2001
Location: UK, bbs.22b.com
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I had the same problem a few years ago. The rolling road operator had T'd a boost gauge into the FPR line for a power run and had not properly secured (with a zip-tie or similar) the FPR reference line back onto the manifold afterwards. The first chance I had to run some boost, the unsecured FPR line blew off and the engine let go within seconds, having melted two pistons.
It sounds as though you may have been more lucky, in that your engine is still running. I hope you haven't sufffered any significant damage to the internals in the process. I'll cross my fingers for you. |
01-22-2004, 12:48 PM | #9 |
Scooby Specialist
Member#: 32118
Join Date: Jan 2003
Location: Houston, TX
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I think the reason why I didn't suffer too much damage is because I had C16 in the tank. And I was running off my pump gas map so that it was extremely rich. Thank goodness. The motor seems fine. I just did a quick pull through the gears and it pulls as hard as before.
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01-22-2004, 12:48 PM | #10 | |
Scooby Specialist
Member#: 32118
Join Date: Jan 2003
Location: Houston, TX
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