I keep getting the P0171 (System too lean (bank 1)) code on my 2008 GSR. My mods are:

• custom dyno tune on Cobb AP -tuned for E85!
• HKS panel filter
• ID1000 injectors
• Fuel rail
• Blaqops kit w/walbro 255

I can clear the code with my AP, but it comes back within a day or less. I have NOT tried my 91oct map on my AP yet (haven't filled up with 91 since E85 is more fun ) to see if the code will still come up on 91.

Also I do NOT have an A/F gauge ( I know...) so I can't really check if it is lean.

Anyone have some suggestions on what I can check for? I don't have any problems with the car, it seems to run great with the code on and runs the same after I clear the code.

It's just kind of annoying with the SES on all the time. I just want to make sure I'm not actually hurting the engine at all. I'm pretty clueless on this type of stuff.

 

you say nothing about your tune. what makes you think you can run E85?

 

Only real way to tell is to buy a Wideband and check for yourself. If you are running lean and "having fun" on E-85 then you are causing problems and it will have serious consequences.

Get a WBO2, you will need one in the future anyways if you plan to keep modding it. I hope you had a tune/AP map for that E-85 you are running, too. What tuner looked over the car and gave you that AP map?

 

Yes, the car is tuned for E85. It was tuned at Dougs Dynopower with the Cobb accessport using the Racetune software from Cobb. I thought we were able to run E85 in these cars with the proper tune and injectors/fuel pump.

I guess I will have to look into a WB. I was trying to save my money for suspension first though

sorry, I will fix that. I thought it was implied.

 

have you checked for boost/vacuum leaks yet? maybe the tune was fine but now that you've got a leak it's sucking in air somewhere it shouldn't. If everything checks out then you probably need to talk to your tuner again.

 

I have glanced around for any leaks, found nothing loose (just by looking - no leak test). But the boost shown on my cobb ap (I know... Once again not too accurate) holds pretty good around 25, tapering to 19 or so psi.

 

If the wideband confirmed that it was too lean then what would you do? Take it to your tuner to have them adjust the fueling, right? Make an appointment with your tuner...

Lean conditions can be caused by a lot of things...a fuel pump weaker than it was when you were tuned or an injector problem. That's the sort of thing that burns holes in pistons. I'd suggest driving it like a granny until it is fixed.

 

boost leak test kit and wb02 is needed to know what's going on, otherwise you're just guessing I'm afraid

 

That's exactly what I'd do

I hope my pump isn't bad, only a couple months old - but I suppose thats possible.

I've been driving it normal for the last couple months and done one trackday also. During the track day I had a sparkplug go bad (apparently from fuel starvation). But otherwise haven't noticed anything else abnormal. Hope I'm not slowing burning up my pistons.

 

P0171 is fuel trim maxed out. It's basically trying to add as much positive fuel trim as possible to get to stoich and it's maxed out +12 LTFT, which will throw the code.

Where you tuned with some 91 oct still left in the tank? If so, once you get pure E85 the trims will sway and you will need a touchup.

Other things that could cause the fuel trim to go max positive is FPR line popped off, but you would most likely have melted a piston by now. The other thing that can contribute to it is a hose off the intake tract, pre turbo, post MAF.

Hope this helps

- Bryan

 

Thanks for the info!

Recomendations for a W/B? and I assume I can install it on the stock exhaust system?

 

I had my FPR line pop off (18:1 AFR at idle) and I never threw this code... then again I don't think I ran this way long enough to max out the LTFT, but STFT was for sure pegged at +12.5 for a brief while

 

Won't throw the code with STFT, only LTFT, and only after a certain amount of time after being maxed.

- Bryan

 

We like the Innovate LC-1 and AEM UEGO

both are in this section and run around 200.00 http://www.mellontuning.com/index.ph...dex&cPath=1_14

You'll need to have your muffler shop weld in the supplied new 02 sensor bung just before the cat in the 3 to 9' o'clock position

 

What Bryan said.

This usually means your injector scaling/latencies are off...

It could be a mechanical problem - get your tune checked out and include proper wideband numbers