Taropatch Posted May 11 Share Posted May 11 (edited) Hello all, I am having trouble finding the cause of my current issue. I rebuilt my 05 OBXT last summer and had an uneventful break-in period. I then began tuning the car with the guys over at cryo and without making that much power we were maxing out the MAF on the stock air box. I thought this was strange because almost every post I have read on the forum states that the stock air box is capable of 300ish hp. The logs were not putting up much more than stock boost. Fast forward and I changed the air box to the Cobb intake with enclosure and now were back with the same issue just with more boost and it has begun to lean out at the high end causing knock. I have double check all connections, smoke tested it, and it looks to be getting good vacuum numbers so I don't think it has anything to do with that. I installed a new MAF during the rebuild and have cleaned it a few times since with out any change. I have zero issues with normal driving, but generally keep it out of boost. To summarize current issues are: 1. MAF sensor maxing out (looking at the tune it has been scaled up 13%) 2. leaning out at higher RPM 3. and the knock around 3800 Here is the short list of relevant mods: RA short block Rebuilt stock B25 heads all new vacuum lines and in bay fuel lines new in tank fuel filter Fuel: DW 750cc injectors Tomei FPR set to 3 bar DW 65c pump intake: stock manifold with phenolic spacers and TGV flap delete Grimmspeed top mount intercooler Kinugawa 16g Mishimoto turbo inlet Cobb intake Grimmspeed BCS Exhaust: Stock headers with Grimmspeed cross over some aftermarket catless uppipe Grimmspeed down pipe and custom catback exhaust Here is the last log after I made sure everything was tight. I probably wont make another pull until I find an issue. Any help is appreciated! R2 3rd gear pull after fix.xlsx Edited May 11 by Taropatch Link to comment Share on other sites More sharing options...
rhino6303 Posted May 11 Share Posted May 11 You might have a fueling issue. The pump might not be supplying enough fuel or getting enough current. Do you have a way of tracking fuel pressure? Link to comment Share on other sites More sharing options...
Taropatch Posted May 11 Author Share Posted May 11 I can see my fuel pressure while idling but i am unable to see real time. I can get a sensor and gauge in the cabin, but Im unsure if RR is capable of logging more than one additional signal. Link to comment Share on other sites More sharing options...
Taropatch Posted Saturday at 07:44 AM Author Share Posted Saturday at 07:44 AM Okay I bought a new gauge and mounted it inside so I could capture a video while logging. At peak boost, 19.7psi, I'm seeing a fuel pressure of 61 psi. Looks like from ~17psi on it stops being the 1:1 ratio that you would expect to see and is a slightly decreased by 2-3 psi. From peak boost till 6000rpm the there is also a 7% increase in injector duty cycle with an increase in AFR from 9.8 to 12.5. Based on the info from the log I don't think it is the FPR. Voltage wise I am reading 14.0V while driving normally. I guess my next move will be to look in the vacation pics for the procedure to test the wiring for the pump and if it checks out order a new pump. Link to comment Share on other sites More sharing options...
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