SkyEyes Posted July 21 Report Share Posted July 21 ::Backstory:: Car has been down for a while. I had a reverse polarity incident that fried the DME relay, but nothing else appeared to have an issue. Recently replaced radiator fan resistor wiring all the way to the central electrics box, but that has nothing to do with the ECU wiring harness. Tried to drive to the gas station today to fill it up and could barely drive 500m before I had to turn around. I didn't have my laptop with me so I couldn't get any logs of the driving behavior, but I did get some logs of similar behavior in my garage after I got home. Car ran pretty much perfectly fine before (recently drove to Laguna Seca for Rennsport Reunion and didn't have any really major issues with driveability) so I'm confused as to what happened... It's obviously getting lean, and I noticed my IAT reading high. I don't have IAT correction enabled, but I'll investigate the sensor after work (ran out of time today). My work keeps me extremely busy, so I haven't checked firmware status, but I can't see that causing these issues. I'm at a loss as to why, out of the blue, the car is borderline undriveable. I am mediocre at best when reading datalogs and looking for signs of issues, and was hoping the experience here could help point out anything in the data that I didn't see. Thanks! PC Datalog - 2024-07-21 2;26;49 pm.llgx PC Datalog - 2024-07-21 2;42;43 pm.llgx PC Datalog - 2024-07-21 2;47;49 pm.llgx 05202023 Rev 2.pclx Quote Link to comment Share on other sites More sharing options...
Adamw Posted July 21 Report Share Posted July 21 I would check fuel press and the 12V supply to the injectors. The only odd clue that stands out to me in one of your logs the lambda suddenly changes from richer than target at the beginning of the log to leaner than target, when all parameters related to airflow and fuel flow were quite stable. So this suggests there may be an external influence on fuel flow that the ecu is not aware of. It appears to get leaner and leaner as load increases so a lack of fuel flow/pressure fits that. It would pay to check there is 12V on pin A5 also (Ign on, ecu unplugged). Quote Link to comment Share on other sites More sharing options...
SkyEyes Posted July 22 Author Report Share Posted July 22 23 hours ago, Adamw said: I would check fuel press and the 12V supply to the injectors. The only odd clue that stands out to me in one of your logs the lambda suddenly changes from richer than target at the beginning of the log to leaner than target, when all parameters related to airflow and fuel flow were quite stable. So this suggests there may be an external influence on fuel flow that the ecu is not aware of. It appears to get leaner and leaner as load increases so a lack of fuel flow/pressure fits that. It would pay to check there is 12V on pin A5 also (Ign on, ecu unplugged). Ok, don't have time to check fuel pressure today, but I did verify 12v at each injector and 12v on pin A5 (ign on, ECU unplugged). I have an adjustable FPR and pulled the vacuum line to verify the diaphram hadn't ruptured. No fuel present on vacuum side so diaphram should be good. Also saw no change in AFR or engine behavior with vacuum removed from the FPR. My DME relay is a pump prime relay and pump comes on as expected when I turn the key, but will need to do further testing on it to verify adequate supply after engine start. Looking at snagging a different FPR to try as well, but only want to do one thing at a time. Quote Link to comment Share on other sites More sharing options...
Earnhart Posted July 26 Report Share Posted July 26 Are you the one buying all the cars on bring a trailer? Quote Link to comment Share on other sites More sharing options...
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