AlphaAssault
15+ Year Contributor
- 480
- 1
- Sep 5, 2007
-
Tyler,
Texas
Ive been having an ongoing problem with lean-induced knock in my GSX during WOT. Im using a TMO logger on my laptop. Important fields are:
small16g: 11psi
knock: 11-17counts above 4000 RPMS
CO2: ~.73-.83V
Timing: dont remember the exact number, but it was being pulled slightly
battery: 14-15V
throttle position is in spec, all other fields are where they should be. Ive made a few other threads where I though some aspect of the fuel system was to blame. Since those posts, I have replaced the fuel pump (old one was a denso 150lph, replacement was the same; no rewire), fuel filter, and injectors (stock). I have also removed the FPR, cleaned and inspected it and its vacuum line, and there is no indication that either are malfunctioning.
The question I come to you with is, what could be causing this lean condition? Im having trouble discerning weather the problem is electrical - something a rewire might fix- or if theres something else wrong with the fuel system. the only reason i am STILL, after replacing all those parts, considering there to be something wrong with the fuel system is that the car slowly loses fuel pressure as it sits. it did this before the fuel system over-haul, and after. on this note, when i replaced the pump, there are three pieces that connect the pump to the car: a lower plastic adapter, an o-ring, and an upper plastic adapter. on my vehicle, the upper adapter was split. i ignored this for 2 reasons: 1) the piece retained its shape, even if some small amount of fuel got through under pressure, it wouldnt be able to leak back into the tank because: 2) it sat above the o-ring, meaning that even if fuel got through that small crack, the o-ring was still in place, preventing fuel from going back into the tank. other than this, i found no fault with the fuel system itself. fuel lines are in good shape, as far as i can tell, and i can neither see nor smell any fuel leaking, weather or not the car is running. as you can see, ive got a wealth of information on this problem, but none of it really adding up to a solution. For the love of god, can someone help me figure this out!
small16g: 11psi
knock: 11-17counts above 4000 RPMS
CO2: ~.73-.83V
Timing: dont remember the exact number, but it was being pulled slightly
battery: 14-15V
throttle position is in spec, all other fields are where they should be. Ive made a few other threads where I though some aspect of the fuel system was to blame. Since those posts, I have replaced the fuel pump (old one was a denso 150lph, replacement was the same; no rewire), fuel filter, and injectors (stock). I have also removed the FPR, cleaned and inspected it and its vacuum line, and there is no indication that either are malfunctioning.
The question I come to you with is, what could be causing this lean condition? Im having trouble discerning weather the problem is electrical - something a rewire might fix- or if theres something else wrong with the fuel system. the only reason i am STILL, after replacing all those parts, considering there to be something wrong with the fuel system is that the car slowly loses fuel pressure as it sits. it did this before the fuel system over-haul, and after. on this note, when i replaced the pump, there are three pieces that connect the pump to the car: a lower plastic adapter, an o-ring, and an upper plastic adapter. on my vehicle, the upper adapter was split. i ignored this for 2 reasons: 1) the piece retained its shape, even if some small amount of fuel got through under pressure, it wouldnt be able to leak back into the tank because: 2) it sat above the o-ring, meaning that even if fuel got through that small crack, the o-ring was still in place, preventing fuel from going back into the tank. other than this, i found no fault with the fuel system itself. fuel lines are in good shape, as far as i can tell, and i can neither see nor smell any fuel leaking, weather or not the car is running. as you can see, ive got a wealth of information on this problem, but none of it really adding up to a solution. For the love of god, can someone help me figure this out!
