Service Engine Soon light came on code P0171
Thread Starter
On The Tree
Joined: Jul 2005
Posts: 100
Likes: 0
From: Iowa
Service Engine Soon light came on code P0171 Bank 1: system running lean......now ive posted this before but now i know the code and it just keeps comming on....ill reset the fuel trims and erase the code then a week later it will come on again......only mods i have that could really effect this is the MTI Lid and a K&N filter.....already cleaned any possible oil off the MAF wires from the K&N and this problem continues to happen. 
.....its been going on for about 3 months now....ive talked to GM Techs and they just do the same thing i do with my Predator and try to charge me for it......but they arent looking for the root of the problem and i have no idea where to even start......looking for some good advice here guys.
Thanks in advance.
.....its been going on for about 3 months now....ive talked to GM Techs and they just do the same thing i do with my Predator and try to charge me for it......but they arent looking for the root of the problem and i have no idea where to even start......looking for some good advice here guys.Thanks in advance.
Thread Starter
On The Tree
Joined: Jul 2005
Posts: 100
Likes: 0
From: Iowa
all injectors are good and still stock MAF......i think ive tracked down the problem....u guys tell me if this would set that code.
the little rubber seal that goes over the egr tube on the intake seems pretty deformed.....probably from when i took it out to cut the tube shorter and i probably didnt put it back in right.....so im assuming it could be sucking in air after the MAF.....my LTFTs stay at 25 at idle if that tells anybody anything....but they do goto 0 at WOT....jibberish maybe but u guys tell me what u think......is that likely the cause?
the little rubber seal that goes over the egr tube on the intake seems pretty deformed.....probably from when i took it out to cut the tube shorter and i probably didnt put it back in right.....so im assuming it could be sucking in air after the MAF.....my LTFTs stay at 25 at idle if that tells anybody anything....but they do goto 0 at WOT....jibberish maybe but u guys tell me what u think......is that likely the cause?
Holy ****...+25% or -25% trims (I'm assuming - since they go to zero at WOT). Definitely fix that rubber seal and see what happens...
Your LTFTs should NOT be that high with as few mods as you have.
Your LTFTs should NOT be that high with as few mods as you have.
Teching In
Joined: Sep 2005
Posts: 3
Likes: 0
Sounds like that could be the problem. Your fuel trims are saying that is adding fuel for a lean condition at idle, at WOT the pcm doesnt compensate for sensor readings, it goes into open loop mode for max power, thats why your LTFT are 0 at WOT. One way to check that gromet at the egr is to spray a quick shot of carb cleaner around it and see if your fuel trims change or it makes the engine rev. If it does then you have a leak there and get'n unmetered air in the engine.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo Good point. I would just highly doubt that is what is affecting it, unless the Predator folks messed up. I was looking at my original Predator tune, and wondering what in the hell I paid that good money for...
I am 99% sure that the stupid O-ring on the EGR is the problem... that is exactly why I took my EGR off. I was going to leave it too. You're getting more air in the engine than the MAF is saying so thats why its running lean.
TECH Veteran
Joined: Aug 2002
Posts: 4,055
Likes: 1
From: Hartsdale, NY
I suppose you could temporarily turn off the test for the erg with your tuning program....
If your running lean in one bank, it could be a bad o2 sensor also; right? Why not swap your Bank one and Bank two front o2 sensors and see if the lean problem moves to the other side....?
If your running lean in one bank, it could be a bad o2 sensor also; right? Why not swap your Bank one and Bank two front o2 sensors and see if the lean problem moves to the other side....?
Thread Starter
On The Tree
Joined: Jul 2005
Posts: 100
Likes: 0
From: Iowa
great.....and thanks, i feel pretty good about myself considering a GM Tech whos been doing this for 19 years couldnt even figure it out.....all he could tell me was "ur running lean, and its because of that new air intake u put on there....put the stock one back on and u wont have any problems"......pfft i knew he wasnt right.....they always try to blame everything on mods here.....but thats good its turning me into a "do-it-myselfer" and im learning alot about my toy in the process.....the car feels alot more responsive now too. 
Awesome man...I love the feeling that you can do things yourself. One of my next mods will be the Helms manual for my car...I just don't trust the people at the dealerships to work on my car.
Thread Starter
On The Tree
Joined: Jul 2005
Posts: 100
Likes: 0
From: Iowa
I dont either and i work at one if that tells you anything lol (educated salesman)......they have jerked me around so many times its not even funny.....ill have to look into a helms book too....thats a great suggestion....because i guess after doing it for 19 years of being a GM Tech u forget how to make a small block chevy run right and just blame it on anything obvious.....i dont want to give dealerships a bad name though....as far as buying a car at one i think thats safe as long as u dont meet some dimwit salesman who knows nothing about what hes selling and tries to make up stuff to cover for his lack of intelligence (we have a couple here).....i just laugh at their sales presentations on the new GTO's and Vettes....u should hear some of the crap these guys try to feed die hard Performance guys n gals like me and u......and about the mechanics at dealerships....if they screw u once theyll screw u again if u let em and come back asking for service....the service dept. can really take u for a loop if u let them....ive seen it all as far as dealerships go....got sick of paying out for something that didnt need done in the first place and ending up still having the same problems....sorry had to let that out lol.
