Need help with a P0171 CEL

[Skarkull]

I looked on the forum, and in most cases people got a P0171 and a P0174 together. I have just a 0171; Bank 1 too lean, any thoughts on why just one side of the car would go lean? My wideband showed way lean, around 17:1, so I shut it down. Any thoughts on why just one side would be lean? Only thoughts that come to mind is the fuel rail cross over line, bank 1 fuel rail, or a bad injector on bank 1. Car was running good, I deployed for 6 months and I came home to this issue. Any suggestions?

 

[skwerl]

exhaust manifold leak?

 

[BruceH]

I looked on the forum, and in most cases people got a P0171 and a P0174 together. I have just a 0171; Bank 1 too lean, any thoughts on why just one side of the car would go lean? My wideband showed way lean, around 17:1, so I shut it down. Any thoughts on why just one side would be lean? Only thoughts that come to mind is the fuel rail cross over line, bank 1 fuel rail, or a bad injector on bank 1. Car was running good, I deployed for 6 months and I came home to this issue. Any suggestions?

O2 sensor went bad? Swap with the other side and see if the cel travels.

 

[Skarkull]

O2 sensor went bad? Swap with the other side and see if the cel travels.

I'll guess I'll start with that. Maybe I'm just looking for an excuse to buy new fuel rails.. lol

 

[TexasBlownV8]

O2 sensor went bad? Swap with the other side and see if the cel travels.

Absolutely try this first. Clear the codes, run it a couple days and see if the code changes.

 

[Renesis07]

...

 

[Alfiedagr8]

What are your fuel trims at idle on both banks? Just cause you have one code it doesn't mean that both banks aren't lean. You need to be I've 20% on fuel trims to set a code. You could be over 20% on one bank and about 19% on the other. So make sure what they are.

What is your baro pressure in psi or HZ if you have a scan tool than can view in HZ.

HZ spec should be about 150-160 HZ KOEO
Or In psi should be 14.0-14.7 psi.


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[Skarkull]

Main issue is that it was good when I parked it 6 months ago so I don't think it is the tune, and I used to run this tune in Germany during the winter as well, so I don't think it is the cold. I was thinking sensor or a fuel system issue. I cleared the codes and drove her some without making any changes. I never got another code, but she got so lean she started to stumble really bad. I kept out of the throttle the keep out of boost, but my boost gauge was showing nearly -20 inHg. Once the AFR seemed to balance out some, I bumped the throttle some but barely saw the boost move. When I got back my car wasn't charging, and Autozone said that my diodes in my alternator had gone out. I went to a shop to get my alternator rebuilt. However, after that drive; over 25 miles; the car was fully charged and starting well. The guy at the alternator shop said that AZ cannot truly tell you what is up with the diodes without ripping the alternator apart. The guy said that he would rebuild it for me, but that if it was charging, there probably isn't an issue. I know the alternator can cause "phantom" codes but can it actually cause issues? I would think that if it was the O2 sensor and the computer saw the bank lean it would enrich the system, so I would be seeing a low AFR like 10-12:1 and still be seeing the lean code. I have an SCT X3 and should be able to log the data. What data should I be logging?

Additionally, why would my boost gauge keep showing vacuum? I know there is an actuator at the back of the S/C that keeps it out of boost at cruise, possible that it is stuck open? Or would the false reading be a symptom of an electrical system issue that would be cause by the alternator.

Lastly I'm about 1/2 tank into that 6 month old gas, but I put some Sta-Bil in it before I parked it, and my other car that I parked isn't having issues, and it's a old Neon.

Thanks for all the help guys, I need to make sure I get this right. Really not looking to replace the motor.

 

[TexasBlownV8]

Check your BPV; it may be stuck open or gone bad.

I nearly fell out of my chair when you were listening to some shit autozone said about your alternator. That's not your problem here anyways.

Observing your afr as you are is a great reason to have an AFR gauge: imagine not having one!

Seriously though, it sounds like a serious vacuum leak (or bpv open), or a fuel issue, including a possible clogged filter (not able to deliver the requested gas the pcm is trying to push through to the injectors). Since you can datalog, you should check the fuel pressure and see what it's doing.
But try the fuel filter if you havent replaced it recenty, and pump out all the old gas while you have it apart, carefully and safely of course.

 

[Alfiedagr8]

Have u checked your MAF to make sure it's not bias in anyway? Cleaning it doesn't mean it's good after. Look at baro pid.


Take a fuel sample.



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[Skarkull]

ok, so what should I be data logging to figure out the issue? There are like 660 different bits of data that I can record, and I have no idea where to start. I had cleared the code, and it came back with the exact same one, so I know it wasn't a fluke. There are like 10 different fuel trims and I'm limited to how many I can record at a time.

Thanks for all your help again.

 

[Skarkull]

So, now I feel like an absolute idiot. I started to work on the car, got her up on jack stands, and started to do an inspection on the exhaust, and swap the O2 sensors to see if the issue switched banks. I opened the hood, and put my light bar up under it, and it was staring me in the face.

The coupling that connects the intake tube to the supercharger had come disconnected from the intake tube. I had air free flowing into the engine with out the MAF accounting for it. So now I have a different issue: hood clearance.

Thanks for all y'alls help, that isn't something that I would have even looked for.

-James

 

[skwerl]

BMR 1/2" engine lowering K member.

 

[Skarkull]

BMR 1/2" engine lowering K member.

I already have steeda motor mounts that will lower the engine, but I'm concerned that my Pypes long tubes will hit my steering shaft if I lower it, so I haven't done that yet. I'm still waiting to hear back from Brenspeed about this as I bought both products from them, so see if their Techs know about any clearance issues. Other option is a cowl hood, and I'm looking into that as an option as well.