system to rich

[dbednarsky]

so here is an interesting one thats got me stumped. I have a 420a in a 96 Dodge Avenger. I bought the motor awhile ago and it was built pretty good. Ground Cams, CP pistons, Rods, etc.... I then turbo'd the car and had it tuned etc.. it ran ok but never great, mainly because the compression was to high and stuff, so after all that I decided to just bring the var back to stock and use it as a daily driver. Problem being it had a head gasket issue, so I brought it to my friend who is a long time chrysler mechanic and owed me a favor to do the job, and it was running good for the last few weeks. Here is where things get interesting. When I got it back from him it still had the walbro 255lph fuel pump, the 36LB/HR injectors and the Aeromotive Fuel pressure regulator. It was running very rich and throwing a CEL code P0172 System to rich bank 1. I swapped the injectors out for the stock ones and everything was good for over a week. This past weekend I had to put the windshield washer tank back in the car, and in doing this I decided to eliminate the FPR since I was N/A again I didn't need it. Went for a drive and the car seemed to run even better now that the stock ECU was controlling everything. I parked the car and took my bike for the rest of the weekend. Well this morning on my way to work the car decided to throw the CEL again for P0172 System to Rich Bank 1. Not sure why, also it seems to run very rough when cold, I just thought maybe because of the agressive CAM grinds. Any Thoughts on this rich issue. Also I am running 93 Octane in it. SHould I try a low or mid grade? Any help is appreciated. If you need more info let me know and I will get it.

 

[Shake_Zulla]

Did you eliminate the stock fuel pressure regulator when you went turbo?

 

[bullettdsm]

Did you eliminate the stock fuel pressure regulator (while leaving in the walbro) when you went turbo?

Just an addition.....

MB

 

[dbednarsky]

shake..... to be completely homest, I don't remember it even having one. All I remember is the line from the pump to the rail.

 

[Shake_Zulla]

shake..... to be completely homest, I don't remember it even having one. All I remember is the line from the pump to the rail.

First of all thanks Mark for the addition. You probably wont have any problems running a stock fuel pump without a fuel pressure regulator but with the Wally it will make you run rich. That could cause your rough idle problem too. Either go back to stock fuel pump or put a stock regulator back on it. On a 96+ it should be underneath the car on the passenger side, 95 its in the engine compartment.