P0171 and P0174 codes. Please help

[JoshH]

The guy I asked about the speedo problem a few days ago is now having a check engine light on. I told him I would try to fix it for him, but I don't even know where to begin on trying to fix it. I do not have a wide band O2 sensor, but he does have an AFR gauge in the truck. From what I've read, the codes come up when the LTF trims add more than 3% fuel for more than 10 minutes. How do I adjust that?

[stroker97k1500]

Maybe have him replace the fuel filter and check fuel pressure and the level of fuel in the tank when this happens for a starting place

[JoshH]

Anyone know if there is any way to tune without a wide band O2 sensor? I'm kind of lost on all of this.

[izaks]

Conditions for Running the DTC

The DTCs run continuously once the following conditions are met:

DTCs P0171, P0172, P0174, and P0175

•

No Throttle, Fuel Injector, Air Flow, Purge Control, MAP, or other Heated O2 Sensor faults active.

•

The engine coolant temperature is -40 - 139°C.

•

The MAF signal is between 1 - 250 g/s.

•

The MAP signal is between 15 - 105 kPa.

•

The IAT signal is between 0 - 152°C.

•

The engine speed is between 400 - 6500 RPM.

•

The vehicle speed is less than 130 km/h.

•

The fuel tank level is more than 10%.

Conditions for Setting the DTC

DTCs P0171 and P0174

The following conditions exist:

The average Long Term fuel trim value is greater than +24%.

[joecar]

I think it's not a matter of adjustment but rather finding and correcting the problem (airleak, fuel delivery,...)...

Did the LTFT's just start pegging recently, or did he add mods, or were they always like that...?

[JoshH]

I think it's not a matter of adjustment but rather finding and correcting the problem (airleak, fuel delivery,...)...

Did the LTFT's just start pegging recently, or did he add mods, or were they always like that...?

AFAIK, the truck has been setting the code since he installed the S/C and purchased the tune for it. I don't think there is a mechanical problem. I'm sure it is a tuning problem, but I have no idea what to adjust or how to adjust it.

[joecar]

If it's a MAF tune then do AutoMAF (same as AutoVE, but applied to B5001 with B0120 set to zero).

If it's a SD tune then do AutoVE.

Either way, a wideband is required.

[JoshH]

If it's a MAF tune then do AutoMAF (same as AutoVE, but applied to B5001 with B0120 set to zero).

If it's a SD tune then do AutoVE.

Either way, a wideband is required.

I guess I'll have to tell him to get a WB02 then. Thanks.