Turbo 95 going EXTREMELY lean (23.8) under tip-in
05-09-2013, 12:27 AM
#1
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Join Date: Oct 2011
Posts: 27
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Turbo 95 going EXTREMELY lean (23.8) under tip-in
INFO about car:
95 Running MSPNP2
99 Swap
6 speed
BEGI S4 Turbo Kit (mostly) with GT2560
Innovate LC-1 with week old sensor.
Stock Coilpacks
Rather New NGK Wires
MSM Plugs with the stock gap (.040?)
550cc injectors - TLFPerformance - under warranty.
No MAF, only IAT.
Okay. As of Sunday I didn't have this issue. Nothing has changed in the engine bay or tune. I did a track day that day and by the end of the day I was having a tip-in stumble and some idling issues. It was very slight, but noticeable. I drove the car home fine with 0 issues.
Monday it got slightly worse.
Tuesday it got pretty bad.
Today was hardly driveable.
When I tip into the throttle, it will go lean for 5-6 seconds before it finally gets fuel and goes again. All other sensor readouts are normal: MAP, CLT, RPM, TPS, everything! There are no corresponding readouts that would cause this as a symptom. (To my knowledge)
Overrun Fuel cut makes no difference whether it is on or off.
My options so far are to
a.) test the fuel pressure - possible pump failure
b.) replace the fuel filter
These seem like an unlikely cause though, since it only happens at tip-in. If I haul *** in the car it still runs pretty damn good. AFRs are good too.
Screenshot:
LINK TO DATALOG>> CLICK HERE For some reason the upload fails every time I try to upload even though it is within the size constraints.
95 Running MSPNP2
99 Swap
6 speed
BEGI S4 Turbo Kit (mostly) with GT2560
Innovate LC-1 with week old sensor.
Stock Coilpacks
Rather New NGK Wires
MSM Plugs with the stock gap (.040?)
550cc injectors - TLFPerformance - under warranty.
No MAF, only IAT.
Okay. As of Sunday I didn't have this issue. Nothing has changed in the engine bay or tune. I did a track day that day and by the end of the day I was having a tip-in stumble and some idling issues. It was very slight, but noticeable. I drove the car home fine with 0 issues.
Monday it got slightly worse.
Tuesday it got pretty bad.
Today was hardly driveable.
When I tip into the throttle, it will go lean for 5-6 seconds before it finally gets fuel and goes again. All other sensor readouts are normal: MAP, CLT, RPM, TPS, everything! There are no corresponding readouts that would cause this as a symptom. (To my knowledge)
Overrun Fuel cut makes no difference whether it is on or off.
My options so far are to
a.) test the fuel pressure - possible pump failure
b.) replace the fuel filter
These seem like an unlikely cause though, since it only happens at tip-in. If I haul *** in the car it still runs pretty damn good. AFRs are good too.
Screenshot:
LINK TO DATALOG>> CLICK HERE For some reason the upload fails every time I try to upload even though it is within the size constraints.
Last edited by dhyde9; 05-09-2013 at 11:17 AM.
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05-09-2013, 02:20 PM
#4
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Join Date: Apr 2006
Location: Athens, Greece
Posts: 13
Total Cats: 1
Wow! what a smooooth map reading. Looks like map sensor is very lazy, propably due to clogged, pinched vaccuum line or if you have an inline filter to this line , it is way too restrictive... Map readings usually are more responsive than tps readings. Your log shows the opposite.
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