Need help trouble shooting P0171
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Need help trouble shooting P0171 This code is for lean bank 1. I just did a TEA S2 head swap on my LS1. The last EFILive had the average for B1S1 at about .450 and B2S1 at about .500. The car smells pig rich. I know the heads will make me lean and I need to add more fuel but I figure I need to fix this first and get the O2s reading close to the same values.
I just got back from a local exhaust shop and they found no leaks in the exhaust. And they confirm that I have no apparent header or EGR/AIR block off plate leak.
So, the excessive lean condition on bank 1 must be coming from the intake. What do I need to be looking for? I will check that the vacuum connection to the EVAP is good as well as the back of the intake. Not sure where the vacuum line goes after that but I will follow it. I will check the vacuum hose for breaks.
When I took the intake off for the head swap I left the fuel rails on so I imagine that the injectors are seated OK. I guess I will check those too.
What else should I be looking for? If I had a intake leak wouldn't that affect the MAP reading? MAP readings seems to be OK.
I just got back from a local exhaust shop and they found no leaks in the exhaust. And they confirm that I have no apparent header or EGR/AIR block off plate leak.
So, the excessive lean condition on bank 1 must be coming from the intake. What do I need to be looking for? I will check that the vacuum connection to the EVAP is good as well as the back of the intake. Not sure where the vacuum line goes after that but I will follow it. I will check the vacuum hose for breaks.
When I took the intake off for the head swap I left the fuel rails on so I imagine that the injectors are seated OK. I guess I will check those too.
What else should I be looking for? If I had a intake leak wouldn't that affect the MAP reading? MAP readings seems to be OK.
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Re: Need help trouble shooting P0171 My LTrim on B1 is at 25 thus the code. But B2 is 0. So, I imagine that it has to be related to B1 somewhere, like injectors. What else could cause a lean condition on just B1? I have search for P0171 and read all the post.
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Re: Need help trouble shooting P0171 I check and followed the vacuum line that originates from the EVAC. It goes all the way around the read of the intake, over by the PCM, and then all the way around the front of the car and comes out just behind the left front wheel well (just under the clutch resevoir) and I followed it around the back of the brake booster and it ended. It is not connected to anything. I did a clutch swap with the head swap and loosened the brake booster to to remove the master cylinder.
Does this go to the brake booster?
Does this go to the brake booster?
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From: CLARKSVILLE,TN
Re: Need help trouble shooting P0171 I may be all wrong here, but since nobody else is giving their $.02 here is mine. I would think if it was a vacuum leak it would effect all the cylinders, not just the drivers side.
I would probably switch the 02's around and check it again to see if it changes just to rule out a bad 02. Also check to see if the header may have burned through the wiring.
Then I'd go and look at each spark plug and see if one looks worse than the rest to try and narrow it down to one cylinder.
Then double check all the wiring connections for the injectors etc.
That's just a stab in the dark, hope it helps...
I would probably switch the 02's around and check it again to see if it changes just to rule out a bad 02. Also check to see if the header may have burned through the wiring.
Then I'd go and look at each spark plug and see if one looks worse than the rest to try and narrow it down to one cylinder.
Then double check all the wiring connections for the injectors etc.
That's just a stab in the dark, hope it helps...
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Re: Need help trouble shooting P0171 Thanks for the suggestions. The line I found was for the washer fluid. I must have pulled it out during the master cylinder swap.
I swapped the O2s before. I think I will do it again or get new ones. These have 54K on them so probably not a bad time to replace. They seem to be working in the AutoTap logs.
I did check the injector electrical connections. I think I will try pulling the intake and fuel rails and make sure the injectors are seating good. Then my friend suggested putting white lithuim grase on the intake gasket and make sure it is seating on the heads.
Thanks again for the suggestions.
I swapped the O2s before. I think I will do it again or get new ones. These have 54K on them so probably not a bad time to replace. They seem to be working in the AutoTap logs.
I did check the injector electrical connections. I think I will try pulling the intake and fuel rails and make sure the injectors are seating good. Then my friend suggested putting white lithuim grase on the intake gasket and make sure it is seating on the heads.
Thanks again for the suggestions.
