Thread: Running lean throwing a "Too Rich" Code?

So whats my next step? Car is running lean.

Is this at wot or idling? If your just idling/ cruising then that afr is perfectly fine. If your wot at almost 16:1 then your engine is going to blow up.

Originally Posted by darkhorizon

You make no mention of a wideband but you are reporting af numbers?

Yes I apologize, should have mentioned that im running a wideband. The AF is 15.6-16.1 at idle, I get 15.6 when put in gear. It used to be 14.8 at idle and 15.1 when in gear. I havent taken it to WOT due to a crappy locked tune with 6* of KR at WOT in 3rd gear.

I will unplug the MAP and see what happens. If the MAP sensor is failed, shouldnt it be throwing a code?

Is there any other reason why I could be running so lean?

Originally Posted by mrfreez

Are you running a wideband O2 sensor or did you just have a tune done? If you changed the O2 sensor for a wideband, did you change both banks 1 & 2 or just one of the O2 sensors? I'm still going to say that the O2 sensor might be bad. Your code said bank 1 (PO172). If that sensor is malfunctioning then it will throw the EGR code too as it relies on the reading from the bank 1 O2 sensor.
If you're running too lean then your engine is making combustion too fast and hot and would trigger your EGR code.

I've had map and maf sensors go bad on me without throwing any code before. However, you are getting an O2 sensor code. Just because you've been through 3 doesn't mean anything. I've replaced O2 sensors that failed within 6 months before. The sensor going into the manifold (bank 1) is a notorious spot on FWD engines to go bad often.

I am running a wideband O2 in a bung as well as the Bank 1 O2 sensor. I have no cats so I got the bank 2 sensor code deleted. Guess I will start by picking up another bank 1 sensor and see what happens. RockAuto has them for pretty cheap, but I think that could be why ive been going through them so fast. What brand do you recommend from RockAuto? Ive been purchasing the "Standard Motor Products" 02 sensors because they had a deal on them.

Quick update.

Finally had a proper day off. I decided to do what all GP owners do when they get a day off, work on the GP. Had some A103s laying around from a while back before I was "advised" to change over to TR6s by a local tuner. Heres what I found:


Needless to say, this may not have been THE problem but its sure contributing. About to take a drive, but it is still sitting at 15.6 A/F at idle. Cleared the codes so lets see.

I'm having the same issue on my mother in-laws bone stock 02 GPGT. Been having fuel system rich for about a year now.

Replaced the o2 last year with a coughboschcough and that didn't matter. I failed a few months later. Just replaced it am month ago. Her LTFT's are solid -12 at idle.
Map is at 32-33 at idle.

Already replaced the FPR a while ago.

Debating on if its the POS bosch o2 sensor and find a stock ac delco or a Denso to throw in there.

I also replaced the MAF sensor a few years ago as it was bad. Not sure if this thing just need a tune since I replaced the maf?

Update:

Repaced EGR Valve
Replaced O2 Sensor w/ AC Delco OEM

Same problem, still commanding lean.

Wanted to give yall a quick update. Pulled the fuel pump after replacing a series of parts isolating the issue(Evap system components not functioning, specifically the purge solenoid has no signal what so ever). Metal shavings in the gas tank and in the fuel pump filter. Talked to a buddy of mine, he as seen this when fuel pumps go bad. It is possible the failing fuel pump is pushing too much fuel into the motor, thus the -20% Fuel Trims.

Got another pump on the way, hopefully this resolves the issue. This is becoming a chore.