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yet another new dsm problem to me

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icuinmyrearview

20+ Year Contributor
41
0
Jan 6, 2003
port st lucie, Florida
ok after sitting for 2 months my 2g fwd is back on the road. and in two months devised yet another way to piss me off. im cruising...about 50mph, lo throttle, and i throw a CEL. i scan..p0170...fuel trim malfunction in bank 1. i understand the code, its sayin im running too rich, lean, blah blah blah for the ecu to compensate. so i start looking at other things...o2 voltage is pretty much .93 across the board (rich for the sunner heat in fl) egt's rising at a normal rate holding around 840C. everything seems to be in order, gas mileage has taken a huge drop however. i reset the ecu, and go on my merry way. all of a sudden fuel cut 15psi@4500 on my Tiny25. i been driving around on lo boost now (10psi) for the last few days, and cant take it anymore. the cel has come back on, i dont always hit fuel cut but now its starting something new. at 4500rpm it feels as thought i have 100,000,000cc injectors. car starts slowing down majorly, and o2's are jumping to the .99-1.05 range. so i go to the trust s-afc and lean out...to about -8% which would of been pretty lean from my past experiences with the 440's and t25. but nothing has changed, still rich up top, o2's havent dropped a bit, doesnt matter how lean i go. as far as fuel.......255hp pump, -6an lines, and an s-afc (1000: 0, 2: -2 3:-3 4:-3 4.5:-3 5:-6 6:-6 7:-6) i know i know the 255hp woth no pump? im still at 43psi at for fuel pressure and i know thats not it. i just dont understand......none of my settings have chhanged whatso ever, but now all of a sudden im richer than bill gates, and regardless of how much i change the s-afc...the o2's do not change. HELP!
 
just re-read what i typed, sorry bout the typos...and i meant to say "255hp with no fpr" somebody's had to of gone through this prob before...i hope....anyone out there? help!
 
fresh set of ngk's new tank of mobil 93, and a new denso o2 sensor........and while the car does feel a little better........it's still very very rich!...only other thikngs are the mas or stock fpr are bad.....fpr should be ok tho....43psi at idle as normal, and 60psi at w.o.t. (12psi) anyone know how to check to see if u have a bad mas? not many local dsmers around here to swap one with
 
watchin my egt's they seem to climb at a decent rate under 25% throttle, even when barely spooling. my o2 voltage ( based on s-afc - i know i know its not acurate but i figured at least it gives me an IDEA as to what my o2's are doing (even if im not exactly at .98 volts at 20% throttle i still know that its running rich)) its ranging from .97-1.05v now according to the s-afc, and the only time the o2's drop below (around .935-.96v) is when im at 100% throttle on 10psi. what the f? im lost on this one. somebody out there please help!!!!!!!!!!!! NO MATTER WHAT SETTINGS I CHANGE ON THE S-AFC...THE CAR FEELS NO DIFFERENT!!!!! I could drop to -50% across the board if i wanted to, and it'd strill be rich. someone help!
 
not that anyone has been responding to this post...but i swapped mas's and the prob was not fixed, on to the fpr...
 
I had a similar problem and come to find out, one of the safc wires had come loose at the ecu. I could go from all + to all - and made no difference in the way the car ran.
 
I had a similar problem, I replace both my o2 sensors with oem ones. If that doesn't help, u might want to try a different ecu if you have a spare one. And yes, check the wiring on the safc, a wire might have came loose. But what I would check first is to see if you have an air leak, while the MAS is reading mad amounts of air coming in, if you are leaking air you are going to run rich, and hit fuel cut while your boost guage shows low boost pressure.
 
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