AFR issues at idle

[99BlownVert]

Hey guys, I have a turbo 93 5.0 fox that is running rich at idle. It runs 11.5-12 at idle no matter how I clock the maf. When you give it gas and air gets going by the meter the air fuel is fine, WOT is great car runs good. Idle is my only issue and it is rich.

Tuner took 80% fuel out at idle just to see what it would do and nothing changed. We unplugged the maf at idle and nothing changed. Its like the maf is not responding until about 2000 rpm. Does anyone have any ideas about this?

I am going to check maf wiring next and see how that looks, thanks.

 

[Blakonblak94]

Where is the MAF located in the piping? Is he able to datalog the voltage that it is reading at idle, and cruise? How is the car being tuned(software)?

 

[99BlownVert]

It in in the fender in the straightest piece possible about 2 feet from intercooler exit. Yes the voltage at idle seemed fine cruise as well. It is tuned with a SCT chip he burned on the dyno.

I have also messed with fuel pressure at idle and it does not change things much either.

 

[Blakonblak94]

Hmmm here's a better question. Where is the wideband mounted? How is your downpipe oriented?

 

[99BlownVert]

Wideband is in the down pipe about 2 feet back from exit of turbo. When on the dyno we kept that one on and put a wideband in the crossover pipe infront of the motor. The AFR matched on each of these locations.

 

[Blakonblak94]

Strange, I know with my longubes my AFR at idle basically means nothing, tuned by feel and vacuum as the pulses are strange. I'm not terribly sure what the issue is. Does it smell like its running fat?

 

[99BlownVert]

Yes it does smell rich at idle, I really dont want to wash the oil down with fuel by letting it idle. Over a long term that could contaminate the oil pretty badly with fuel don't you think?

 

[Blakonblak94]

Its possible, but it would have to idle for some time I would imagine. Maybe try and pull fuel until it kills it, then try adding some bit by bit to get it close.

 

[99BlownVert]

I guess its not a huge deal I will just keep an eye on it and change the oil sooner. Car runs great otherwise

 

[Blakonblak94]

Let us know if anything improves.

 

[gmcconn1]

What injectors does it have? When the tuner changed the maf curve to reduce the fuel, did the injector pulse width change?

 

[99BlownVert]

It has ford racing green top 42's. I honestly am not sure he did everything he could and it did not change.