P0171 Engine Code

[BrettxReitz]

P0171 Mean Lean On Bank 1 Of The Engine. My Cars A 1996 RT/10 ROE Supercharged. My Car Has 19,700 Miles On It. Well, I tested my bank 1 sensor 1 o2 and was like brand new. Hits a whole volt. Tested my map and hit the spec numbers from 0-20psi. I went over the motor with propane and no rise in Rpm. My pcv was good but don't matter since its blocked off which is a ROE doing. There's no exhaust leak. 55psi fuel pressure so I assume a good fuel pump and filter. Cleaned Air box. And checked the bank 1 injectors. I didn't unplug them I back probed the harness wires and they all hit the same x.x volts. I don't know what else to do. It comes on every 70 miles or so and my long term fuel trim hits plus 33%. Engine runs perfect all the way thru. Is there any more feed back you can give me. This Is Not A Easy Task To Solve Anymore. All other fuel trim was with in + or - 10% when the light came on. Third Time The Light Came On This Year.

 

[speedracervr4]

Have you tried adding fuel via the VEC? Aftermarket headers? Where are the O2 sensors located if they are aftermarket headers?

 

[speedracervr4]

Also have you checked the plugs lately,specifically the two rear ones? The Roe manifold will foul out the rear plugs easily compared to the other cylinders.

 

[BrettxReitz]

I got Belanger Headers, the upstream o2 sensors are where all cylinders join as a whole pipe in the back of the headers. I actually just thought about checking plugs earlier today for blackening. Would that be a cause or effect to the problem. Also I never bought the software for the vec2 so I never thought about adding fuel... Didn't know that could be done. I sent my programmed card to ROE when I first bought the car to see what gas it was set up for and he said it was a custom set up and didn't mention anything was wrong with it except high timing for the most power. I also thought of test pressure when hot? Could the down stream o2 affect it at all?

 

[speedracervr4]

A fouled plug will show a lean issue. I've heard of people having issues (fuel trim) with the 02 sensors in the tube as opposed to the collector, that's why I asked the question. I also have Belanger headers and have my 02 sensor in the same location as you described.

I had a similar issue with my 99 Roe supercharged GTS and Sean sent me a card with added fuel and the problem went away. He had all my tunes on file since he did the dyno tuning on it. Each engine is different and some need more fuel than others.

Down stream 02s will not affect fuel trims, they monitor the cat efficiency.

What do you mean by "test pressure when hot"? Compression test?

 

[BrettxReitz]

Make sure my fuel pressure is still at 55psi after hitting 195 degrees. I'll be checking my back driver side #9 cylinder today and if its fouled I'll contact Sean and ask him to add more fuel. Only thing is he's out of the office till the 16th. I know fuel filters are to be changed every 20k and mines almost at 20k. I heard there not so easy either. Also the way I tested the injectors as I described... Is that a effective way. I touch a screw driver to them to hear there pulses but there under the fuel rails.

 

[speedracervr4]

If your rear plug is fouled, I would just change it and see if the issue is resolved prior to having Sean tweak the VEC tune. Yea I'm not sure I would change the filter without narrowing it down to a fuel deliver issue. You could tape a fuel pressure gauge to your windshield and do some WOT runs to see how the fuel pressure is under boost to determine if it's a pump/filter issue.

I know they make noid lights for testing injectors, but I'm not sure if your testing method is right or wrong.

Do you have data-log abilities? I know you said you tested the 02 sensors, but it might be worth data logging it to see if they cycle properly.

 

[BrettxReitz]

My plug was carbon all up. My cars load was 30% at the time the light came on. I'll talk with Sean about modifying the tune then replace plugs. The o2 was replaced 1k miles ago. I found receipt from last owner on bank 1 upstream. I thought of a intake manifold leak as I heard they were popular but you can badly get at it on the side but my head gaskets were replaced to so I'm sure the gaskets fine. I'll test the pressure when hot next Saturday when I'm coming home from a show. I hope the modified tune and plugs fixes it. I'll let Keep you posted when this happens as he's out till the 16th. You have any more advice that u can think of??

 

[speedracervr4]

I found an old email from Sean when I had the same issue and here is what he said after I replaced the up stream 02 sensor.

"With fresh O2's and the lean condition (adjusted by way of adaptives), it
may just need a couple % more fuel in closed loop."

I may have a spare VEC disk, but I'll have to dig it out. You'll need a card reader/writer as well if you plan on adjusting it yourself.

Sounds like you're on the right track, you may also have to remove some fuel from the rear two banks to limit the fouling of the plugs. It's a design flaw with the manifold, but it can be overcome with individual injector fuel trims (Via the VEC).

 

[BrettxReitz]

Great. Thanks, I been thinking about it and that sound the most logical to me. I'll inform Sean with this message to put him on the right track. Thanks Alot Man!