a little background first.

98 ex coupe built y8 on 15psi.
PTE 880s with INLINE 10w 10ohm resistors (had someone solder the resistors in my obd2-obd1 injector harness adapters, they soldered them in the wrong side, so the resistors were going to the colored wires to the injectors instead of the yellow/black wires on the injectors) so i called up precision and they said polarity didnt matter, so i just cut my harness and swapped the yellow/blacks with the colored) hope someone is still with me. basically colored wires from harness now go to opposite side of the injectors and have an inline resistor, and the yellow/black wires are on the other side of the injectors. (reversed polarity).

car was put back together a week ago or so, and all was good, cranked right up, no problems, tuned very easily, put a couple hundred miles on it before yesterday. met up with a friend at the gas station ( i was datalogging), cut the car off, and he says, man smells like plastic burning. look under the hood, nothing out of the ordinary (i cant smell either so i dont know if he was smelling stuff or what). went to crank the car and cranked and immediately stalled, so i added about 10% fuel in the idle areas, cranked right up, all was good. drove around for atleast an hour (raced around a little/alot), never any sign there was a problem, drove home fine. took the laptop in and started fine tuning some areas that needed it and saved the file.

took the laptop out this morning uploaded the file and cranked the car, cranked right up and pegged lean at idle, tried revving a little, same thing, barely running i added 10% fuel 3 times, and still pegged lean. tried to drive it but it was like the pump was barely adequate to keep it running at idle much less any load. so i hopped in my truck and took it to work.

get home this evening and it starts right up, pegged rich on the same tune. rev it and it goes lean, any load dead lean. try to lean out the idle and nothing still too rich. then after about 5 minutes of idle it decides to lean out, just like this morning.

first thing i figure is injector drivers in the ECU, so i pull the ecu (p28, neptuneRTP,demon). take it inside and see no signs of heat, and no clue how to test the injector drivers or any other components i start testing the obvious stuff. resistors i know should be the same across them as any other with the same color scheme, so i start there.

R49 is next to J1, well, its the same thing as about a half dozen other resistors that all show 10ohms on the multimeter. on R49 i get 365ohm..... does that mean its bad, and if so what does it control? is it connected to my issue in anyway?

sorry so long, but i'm at a loss and i'm not the type to just throw stuff at it without proper diagnosis... so i'm willing to learn, try, whatever.

 

tuned in what? Crome? --> export maps, open new base, import & rebuild.

based on what you're saying I'm not thinking hardware.

 

Running Neptune, I've loaded a few different files, all the same problem. My check engine light is out, I'm going to fix that and make sure its not solid before going any further.

I also ordered a walbro since mine was stock and had to be being pushed very hard it could be toast.

I wish I had a fuel pressure gauge in the bay, don't think my snap on fuel pressure tester has the parts to attach to my fuel system for testing but I'll look.

I know all four injectors are firing verified with a noid, also tested resistance across the injector coils through the inline resistors and all are 12.2-12.3 which to me shows no signs of a problem there.

Any suggestions feel free to throw them out.

 

was able to drive it for a minute tonight. was fine for about a mile, AFR was perfect during cruise and WOT, so i turned around and headed home. halfway home it started going real lean, by the time i got home it was back to barely idle (real lean).

pretty sure the fuel pump is trash based on that, so i'll leave it alone until the walbro gets here.

 

sounds like a good precaution, all though that wouldn't explain why you can't get your idle away from super rich...

 

You're right but last night that problem didnt exist, weird.

 

if your problem with lean idle went away periodaclly id have to say pump. did you get it and did it fix your problem. sorry for spelling im a diesel mechanic lol but an inbay B&M gauge is what i have in mine and its very helpful when diagnosing fuel problems. also ive HEARD just heard that p28 is better left untouched...? i run p28 with chrome on 8lbs of boost last summer. never had a problem once.