Looking for help: Fuel trims maxed & Timing advance going nuts?! Stock engine!
08-09-2008, 12:19 PM
#1
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Looking for help: Fuel trims maxed & Timing advance going nuts?! Stock engine! Hey Everyone.
ive got an 89 iroc-z w/ a '03 5.3L motor.
The engine is stock except for:
1 5/8" LT headers
No cats
LS6 intake
LS1 injectors
CAI
LS6 valve springs
Magnaflow catback
O2's are just into the y-pipe, bout 4-5" behind the header/y pipe collector.
The car's LT Fuel Trims are reading 25 at idle. They move as i move the RPM's up (Please see my Scan ive included) but they stay pretty high.
Also at about 1500rpm the timing advance is going sky high and at idle the advance is jumping everywhere causing teh engine to surge.
The only changes ive done to the tune are deleting vats, setting up my fans, and changing my tire height for the speedo.
Despritly seeking help!
Im attaching a copy of my scan.
ive got an 89 iroc-z w/ a '03 5.3L motor.
The engine is stock except for:
1 5/8" LT headers
No cats
LS6 intake
LS1 injectors
CAI
LS6 valve springs
Magnaflow catback
O2's are just into the y-pipe, bout 4-5" behind the header/y pipe collector.
The car's LT Fuel Trims are reading 25 at idle. They move as i move the RPM's up (Please see my Scan ive included) but they stay pretty high.
Also at about 1500rpm the timing advance is going sky high and at idle the advance is jumping everywhere causing teh engine to surge.
The only changes ive done to the tune are deleting vats, setting up my fans, and changing my tire height for the speedo.
Despritly seeking help!
Im attaching a copy of my scan.
08-09-2008, 09:02 PM
#4
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They are maxed at + 25%.
I thought i might have an exhaust leak before my O2's, so i checked all & re-did my seals, no dice.
The tune is an OEM 5.3L tune, with my injectors ajusted for the LS1 injectors, Vats Delete, Fans ajusted, wheel height changed.
Tune is attached
I thought i might have an exhaust leak before my O2's, so i checked all & re-did my seals, no dice.
The tune is an OEM 5.3L tune, with my injectors ajusted for the LS1 injectors, Vats Delete, Fans ajusted, wheel height changed.
Tune is attached
08-10-2008, 08:27 AM
#5
Where did you get this tune? It has had a lot of things changed. I looked at a stock tune in the hp tuners repository and it is not even close to yours. Your ve table looks more like a gto or z28 than a 5.3l truck. You might want to do a compare to a stock truck table to see what I mean. Have you cleared the long trims in the scanner and aloud them to start over from scratch.
08-10-2008, 06:08 PM
#6
why are the O2s in the Y pipe instead of the headers? There is so much heat loss back there, even if you find a real problem, this one will present more. The trims may be + from a tiny air leak at the point where the Y pipe and headers meet... Also, they are guaranteed to be lazy being that far back in the pipe from heat loss. You can work the integrator delay to help the fact that they will be updating "late", but the heat loss is gonna be a killer at idle. It could mimic heater failure and be a large contributor to the + trims as well.
