Guest rhd_2jz Posted September 20, 2007 Share Posted September 20, 2007 ok i have a jspec tt engine with Decat,3in dp&ex,restrictor ring installed,fmic,and a BC.. Now i have a decent wideband 02 meter that is telling me that i am getting into 14-16 to 1 fuel mix under WOT but i am only running 12-13 psi 14 on a spike.. any ideas what might be causing this.. not hitting fuel cut either:search: Link to comment Share on other sites More sharing options...
Homer Posted September 20, 2007 Share Posted September 20, 2007 If you're hitting those sorts of AFR figures on WOT at 12+psi then you would have a melted engine by now. Are you sure the wideband sensor is working correctly? Where is the WB sensor mounted? What sort of rpm are we talking about, and what gear? Link to comment Share on other sites More sharing options...
n boost Posted September 21, 2007 Share Posted September 21, 2007 U might have a dodgy sensor. U haven,t dropped the sensor as they can be very delicate and can easily be damaged. Link to comment Share on other sites More sharing options...
Guest rhd_2jz Posted September 21, 2007 Share Posted September 21, 2007 If you're hitting those sorts of AFR figures on WOT at 12+psi then you would have a melted engine by now. Are you sure the wideband sensor is working correctly? Where is the WB sensor mounted? What sort of rpm are we talking about, and what gear? Well im in the midst of getting another one to verify and no it hasn't been dropped or mishandled its about 12-14 inches back from the turbo's.... obviously i havent been beating the car due that.. i gave everything a once over plugs dont look bad no sparkles on the porecilen no drastic changes in compression only few 2-3 psi down the line... the afr starts to go south about 4000ish 3rd & 4th gear and im sure 5 and 6 also Link to comment Share on other sites More sharing options...
Ian C Posted September 21, 2007 Share Posted September 21, 2007 Well if they are short bursts at 14:1afrs it won't have time to heat up too much but it'll still be detting so that's not good. Maybe your fuel pump is weak or there is a blockage in the line, filter perhaps? Is it a US car and runs off a MAF sensor? Do you have anything that can datalog injector duty cycles? -Ian Link to comment Share on other sites More sharing options...
TLicense Posted September 21, 2007 Share Posted September 21, 2007 ok i have a jspec tt engine with Decat,3in dp&ex,restrictor ring installed,fmic,and a BC.. Now i have a decent wideband 02 meter that is telling me that i am getting into 14-16 to 1 fuel mix under WOT but i am only running 12-13 psi 14 on a spike.. any ideas what might be causing this.. not hitting fuel cut either:search: Have you got an aftermarket fuel pressure regulator? Do you have any means of measuring the fuel pressure and the inlet air temps? Link to comment Share on other sites More sharing options...
Guest rhd_2jz Posted September 21, 2007 Share Posted September 21, 2007 Well if they are short bursts at 14:1afrs it won't have time to heat up too much but it'll still be detting so that's not good. Maybe your fuel pump is weak or there is a blockage in the line, filter perhaps? Is it a US car and runs off a MAF sensor? Do you have anything that can datalog injector duty cycles? -Ian Yes there is an safc installed in the car but as of right now its bypassed because i just wanted to make sure i wasn,t having issues there.... i haven't watched it really closely but im pretty sure nothing over 80-5% duty....there is an aftermarket fpr brand name not a cheapy, set at stock fuel pressure and increases 1:1 with boost pressure...this is a j-spec engine with the map sensor... and im running a walbro 255 which is relatively new (year old) and i have checked the lines and installed a new filter..that is where i went first thinking i had blockage Link to comment Share on other sites More sharing options...
Chris Wilson Posted September 21, 2007 Share Posted September 21, 2007 Monitor the fuel pressure? Link to comment Share on other sites More sharing options...
Ian C Posted September 21, 2007 Share Posted September 21, 2007 Well if you are running lean it's either: 1) unmetered air getting in 2) duty cycle too low 3) not enough fuel reaching the injectors 4) O2 sensor reading wrong. 1) is almost impossible on a MAP spec to have this happen but if your lower intake runner gaskets are leaking air, that's where it'd be. 2) This would be caused by the stock ECU getting the "wrong" signal. Could be the AFC having a bizarre influence, I've seen that before. Could also be a wiring issue giving the ECU bad signals. 3) This would be incorrect fuel pressure, which can be caused by a weak pump, a blockage, a malfunctioning fuel pressure regulator... 4) This should be easily provable with common sense if it's 3 to 4 full points out. If you find you are idling smoothly at 18:1 it's probably buggered -Ian Link to comment Share on other sites More sharing options...
b_have Posted September 21, 2007 Share Posted September 21, 2007 Well if you are running lean it's either: 1) is almost impossible on a MAP spec to have this happen but if your lower intake runner gaskets are leaking air, that's where it'd be. -Ian If it has an air leak here it will run rich (would have to be a considerable leak) Link to comment Share on other sites More sharing options...
Ian C Posted September 21, 2007 Share Posted September 21, 2007 If it has an air leak here it will run rich (would have to be a considerable leak) On boost yes, but on vac it'd be lean, however in this case as we are talking about on boost, you're right Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted September 21, 2007 Share Posted September 21, 2007 If it only after 4,000 RPM open loop, then it has got to be a MAP sensor problem or injector related, or drooping fuel pressure anything else would either show up as soon as + boost is reached, IE FPR, or air and water temp sensors would have an effect, IE rich on low RPM - boost. Link to comment Share on other sites More sharing options...
Guest rhd_2jz Posted September 22, 2007 Share Posted September 22, 2007 alright iv'e gotten a lot of info from everyone here... thanks a bunch guys it is appreciated.. i checked my fuel pressure today i got 32 at an idle and 45-47 under boost pressures...I guess i just need to start at ground zero with the electronics and work my way up Link to comment Share on other sites More sharing options...
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