Bank 1 bank 2 running rich

[GSkiner]

I have a 2014 2500 6.4 and am having trouble fixing a P0172 and P0175 fuel system rich on bank 1 and 2 . I have replaced MAF, PCM update, throttle body and now 4 O2 sensors that the dealership diagnosed. Non have fixed the issue. It will idle fine but dies when I come to a stop . Any info would be appreciated.

 

[2003F350]

Sounds to me like an injector issue then, or possibly a dirty air filter that isn't letting enough air in. Fuel system rich is either a sensor, you're getting too much fuel, or not enough air.

 

[crazykid1994]

May need to get a live data scanner so you can check the injectors as well as check the o2 sensors to see if they’re functioning properly. Could be as simple as a computer malfunction. May need to do a full reset on the computer. 2 ways to do that. Pull battery or get Alfaobd and go into the engine computer and hard reset it.

 

[62Blazer]

I question exactly what was involved in the "diagnostics" of the dealership. Don't take this the wrong way, but what reasoning did you have for replacing all of the other parts? Was some sort of diagnostics/trouble-shooting performed to make you believe the parts had issues, or were did you just start replacing parts? After you replaced those parts and the problem was still there, did you reinstall the original parts? The reason I ask that is just because a part is new doesn't mean it's good. Especially if you start replacing OEM parts with generic chain parts stores stuff, electronics and sensors are the worst. I've actually seen "new" parts causing more issues or hiding what the original issue was.

 

[GSkiner]

It started when I got my oil changed and they replaced my air filter. About I week later I drove to work and it ran fine when I started my truck after work it stalled and would not idle . I opened the hood and found the intake was off the throttle body so I put it back on and it didn't fix the issue. So I looked up possible issues to cause it to throw those codes and at the top of the list was mass air flow sensor. That did not work and the next was a possible PCM update that's when I took it to the dealership and they diagnosed it with 3 bad O2 sensors and one lazy one and wanted to charge 1600 . So I ordered the parts my self and changed them out in about an hour and saved my self a 1600 charge but unfortunately am no closer to a fix

 

[csuder99]

Ah the classic "parts cannon".... Clearly the dealership is incompetent, they can't even change an air filter without screwing it up so their "diagnostics" isn't worth the electrons it's stored in. What's the likelihood all 4 O2 sensors develop an issue at the same time ?

As already suggested, a scanner with live data will be helpful. The rich condition is a symptom so look at the inputs the PCM uses: Intake and coolant temps, MAF readings and see what the fuel trims are.

 

[GSkiner]

So my buddy checked that with his scanner and he didn't see anything or any reason it would be doing it . Nothing indicating the injectors are possibly clogged or not working correctly.

 

[62Blazer]

It started when I got my oil changed and they replaced my air filter. About I week later I drove to work and it ran fine when I started my truck after work it stalled and would not idle . I opened the hood and found the intake was off the throttle body so I put it back on and it didn't fix the issue. So I looked up possible issues to cause it to throw those codes and at the top of the list was mass air flow sensor. That did not work and the next was a possible PCM update that's when I took it to the dealership and they diagnosed it with 3 bad O2 sensors and one lazy one and wanted to charge 1600 . So I ordered the parts my self and changed them out in about an hour and saved my self a 1600 charge but unfortunately am no closer to a fix

The air intake tube coming off would point me in that direction. If everything is running fine, and than suddenly you have issues that start right when the intake tube comes odd, I would concentrate on that area. Anything else, like the O2 sensors, going bad at that exact moment would be a huge coincidence.....and as said above what are the chances that all 4 O2 sensors went bad at the same time....
Back to the intake tube, MAF, and throttle body area. I would take a close look around the area to see if anything was damaged in that area when it came loose. Are there any wires, connectors, or hose in that general area that may have gotten pulled out or loosened, either when the tube came off or happened accidentally when you put it back on? The MAF is on the air box housing and I could see wiring getting damaged. Maybe just leaning up into the engine compartment when putting the parts back on snagged something?
Back to the codes and ones that point at sensors. Keep in mind that codes do not specifically say the sensor itself is bad. Rather is says the signal from that circuit is bad, which means it could just be a bad wire or connector and the sensor itself is fine. In my experience of working on cars over the years I would say at least half the time you get a code related to the signal coming from a sensor, it's not the sensor itself but rather something to do with the circuit. I've personally seen a guy replace an O2 sensor 3 times and still get a code. I'm by no means a mechanical genius, but it took my about 2 minutes to find one of the wires going from the O2 sensor up to the engine bay was frayed.

 

[GSkiner]

So ended up fixing the issue yesterday. It ended up being the MAP Sensor I changed it out and could tell instantly it was fixed . 23 bucks and it fixed the issue. Thank you everyone for your input and assistance it is greatly appreciated

 

[2003F350]

So ended up fixing the issue yesterday. It ended up being the MAP Sensor I changed it out and could tell instantly it was fixed . 23 bucks and it fixed the issue. Thank you everyone for your input and assistance it is greatly appreciated

Glad you got it fixed.

Lesson for the future, though: Just because you have a code for a sensor doesn't mean the sensor is automatically bad. I can go on for hours about how I got various codes for various sensors that weren't actually bad.

Instead, those (4) O2 sensors were simply telling you it was running WAY too rich and that you had a problem. Couldn't tell you what the problem was though.

The latest issue I had was on my old truck, it would not idle, heck after a while it wouldn't even run enough to give the tech any data. Turned out to be a MAP sensor gone bad, but because they couldn't get data and there's no real test for the MAP sensor unless the truck is running per their training, what would really point them toward it? They ended up putting in a call to the Chrysler Proving Grounds, got a call back to replace the MAP sensor (which was on backorder for like 3 weeks), and the truck fired right up and ran great again. In the meantime, I'd already bought a new truck and they gave me full trade value for the old one.

Long story short, when you have a rich condition, you've gotta start at the other end and work your way through.

 

[crazykid1994]

My work van throws a running rich code occasionally and you can feel it stumble or buck when you try to accelerate. It’s been to the dealer and a seperate mechanic as well. Originally the dealer replaced the transmission saying the bucking was the trans failing at 20,000 miles but i had not thought that to be the issue. I’m at 65,000 miles now and it’s been checked on 3 different occasions. 2020 gmc savanna 2500 with the 6.0 v8 and 6L trans. When they reset the computer the issue is “resolved”. It comes back a week or 2 later after the computer is relearning everything which points me to an electrical issue like a sensor failing. They won’t listen because it goes away or they can’t duplicate and the computer doesn’t show any bad sensors. Glad you got yours taken care of. I hate to say that I’ve had 2 vehicles that were gm products with stupid failures. Had a used 2000 Chevy classic that overheated because the ac didn’t work. When the ac failed the cooling fans wouldn’t turn in until around 220-230° and they would cycle off around 210°. Ended up loosing the lower intake gasket around the water jacket. I had fixed the ac once in it but it was a beater car so we had been planning on trading it in anyways. I used jb weld epoxy to patch the intake. Worked good enough to get to the dealer and trade the car. Drove all the way there with the heater on. My father had a 03 Silverado 2500 that the computer took a crap on him. “Reduced power” light would pop up on the dash occasionally and you could tell it was running rough. Reset the computer and it would drive fine again.