Fuel trims change at random???

[rstchris]

I tune my safc perfect and all the sudden it goes way lean, so I tune it again and at random it will go back to rich. I ended up finding the happy medium between the two but that's about 12.9-13.2 cruise/ idle then 15.5-15.9 cruise/ idle. the only thing consistant is WOT. It's always in rich "mode" when cold then switches and at random while warm will go back and forth. I also noticed my car is not making corrective fuel changes "closed loop" and the only code it's throwing is "MAP" I think i have a bad connection inside the ecu on that cause the signal goes to the ecu connector. Will the code i have keep it in open loop and why does my fuel system jump around?

 

[zhjiln]

did you calibrate the wideband outside of exhaust?

 

[rstchris]

Yeah, but that's not even close to the problem. It's like after driving a while it would seem like my fuel pressure would drop 8-10psi then at random go back up. I know that's not the case but that's how it acts. I have a 170* thermostat, I don't think it would make that much of a diff. though.

 

[rstchris]

So I hooked up a scan tool today and realized the o2b1 volts were "0" so now that my o2 is working properly I can go into CL. I"ll drive a bit later and make sure it's not gonna switch around on me.

 

[rstchris]

Problem solved, I put in the 660's and tuned in open loop, then plugged the NBo2 and it runs like a dream.