P0171 Lean code
01-07-2009, 07:30 PM
#1
Senior Member
Thread Starter
Join Date: 03-09-08
Location: Brandon, Florida
Posts: 1,934
Likes: 0
Received 0 Likes
on
0 Posts
P0171 Lean code
UPDATE:Ruled out the MAF calibration. It was tuned accurately by Fast98. Tried different tunes and same result. I'm throwing the P0171 at idle along with misfire in cylinder 1. I hooked up my interceptor and had 16 misfires in a matter of a couple of min in cylinder 1.
Last edited by flash13brandon; 01-14-2009 at 10:12 PM.
01-07-2009, 10:20 PM
#7
Senior Member
Thread Starter
Join Date: 03-09-08
Location: Brandon, Florida
Posts: 1,934
Likes: 0
Received 0 Likes
on
0 Posts
I have cleaned MAF and TB.
Tuned it back to Stage 2.
Reset fuel trims.
Checked to make sure hoses and sensors and couplers are connected.
I even tried turning off the feature on HPT that leans it out when decelrating.
Tuned it back to Stage 2.
Reset fuel trims.
Checked to make sure hoses and sensors and couplers are connected.
I even tried turning off the feature on HPT that leans it out when decelrating.
01-07-2009, 10:47 PM
#9
New Member
Join Date: 06-29-08
Location: Dallas
Posts: 102
Likes: 0
Received 0 Likes
on
0 Posts
i know it should be that way. but i had a p0171 cuz a dirty air filter once.
Pcm ****
01-08-2009, 12:08 AM
#11
Senior Member
Thread Starter
Join Date: 03-09-08
Location: Brandon, Florida
Posts: 1,934
Likes: 0
Received 0 Likes
on
0 Posts
I have the AEM dryflow and I checked it tonight and its not dirty. The maf settings have been tuned 3 seperate times. Once by Fast98, once set to stage 2, and once to a custom 42s tune. If anyone has specific MAF settings that could eliminate that PLEASE LMK.
01-08-2009, 06:36 AM
#12
Senior Member
Join Date: 03-03-06
Location: Pittsburgh, PA
Posts: 4,958
Likes: 0
Received 0 Likes
on
0 Posts
Fuel trims need to be scanned and the results used as correction into your current MAF calibration.
01-08-2009, 08:31 AM
#13
Senior Member
iTrader: (5)
Join Date: 02-06-08
Location: louisiana
Posts: 932
Likes: 0
Received 0 Likes
on
0 Posts
Im using fast 98 tune and ive had no problems it was throwing that code a week ago and i adjusted the filter and its been gone ever since. I guess you checked all other conections vac lines and the boot to the tb
01-08-2009, 11:50 AM
#15
Senior Member
Thread Starter
Join Date: 03-09-08
Location: Brandon, Florida
Posts: 1,934
Likes: 0
Received 0 Likes
on
0 Posts
Ya I checked all the hoses and couplers. What gets me is that it is only at idle. Does anyone have good MAF settings for 42s and K&N Typhoon?
01-08-2009, 01:32 PM
#16
New Member
Join Date: 03-19-08
Location: Connecticut
Posts: 43
Likes: 0
Received 0 Likes
on
0 Posts
I know this may sound strang but when I bought my car new I would get 171 every other week. Finally at one of my visits to the dealer the mechanic took it apon himself to chase after that code again. turns out GM says its actually the airfiler that causes it. beingmisshaped or dirty causes the air to spirrel past the maf and a misread. I havent had a code for the last 4000miles and im stage 2. Hope this helps.
01-08-2009, 01:55 PM
#17
ok... tuning the maf is more than just uploading someone elses settings. maf tuning is driving around and logging the maf error %. then copy and paste special (multiply by half) on your current maf table. do that until its dialed in to within + or - 3%.
heres another thought. did you fart with the PCV? alot of people try to throw a breather filter on the valve cover and block off the intake to avoid getting oil in the intake, this will throw a lean trim code.
heres another thought. did you fart with the PCV? alot of people try to throw a breather filter on the valve cover and block off the intake to avoid getting oil in the intake, this will throw a lean trim code.
01-08-2009, 07:10 PM
#19
if tuning the maf by error % doesnt solve anything, replace the maf.
I was going to suggest checking the injector short pulse adders, but this should not be an issue if you use the gm tune with the gm injectors. thats usually only a problem with the 60#s.
I was going to suggest checking the injector short pulse adders, but this should not be an issue if you use the gm tune with the gm injectors. thats usually only a problem with the 60#s.
01-08-2009, 10:19 PM
#20
Senior Member
Thread Starter
Join Date: 03-09-08
Location: Brandon, Florida
Posts: 1,934
Likes: 0
Received 0 Likes
on
0 Posts
would a bad maF cause it to throw a code only at idle??
01-08-2009, 11:18 PM
#21
New Member
Join Date: 07-05-08
Location: Lima, OH
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
sorry to threadjack dude but i'm having the same problem...but from what i understand is theirs either a lack of air in the cylinder or the injectors aren't able to compensate for putting in so little fuel...my thoughts are swap to a smaller pulley and maybe that will solve the problem, of course you're going to have to retune for the smaller pulley but does that make any sense to anyone else? Increase the amount of air the s/c is putting into the cylinders at idle so the injectors won't have to dump so little fuel in eliminating the random misfire?
01-09-2009, 12:19 AM
#22
that makes no sense. if you are throwing a lean fuel trim code, why would you add MORE air to make the mixture leaner.
Smaller pulleys aren't the answer
Lean fuel trim means the computer is having to add more fuel because the o2 sensor reads a lack of fuel in the exhaust. If the ecu has to add more than a certain amt of fuel to correct the afr, it will trigger the code p0171.
Smaller pulleys aren't the answer
Lean fuel trim means the computer is having to add more fuel because the o2 sensor reads a lack of fuel in the exhaust. If the ecu has to add more than a certain amt of fuel to correct the afr, it will trigger the code p0171.
01-09-2009, 12:59 AM
#23
Senior Member
Join Date: 03-03-06
Location: Pittsburgh, PA
Posts: 4,958
Likes: 0
Received 0 Likes
on
0 Posts
01-09-2009, 02:14 AM
#24
New Member
Join Date: 07-05-08
Location: Lima, OH
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
sorry to threadjack dude but i'm having the same problem...but from what i understand is theirs either a lack of air in the cylinder or the injectors aren't able to compensate for putting in so little fuel...my thoughts are swap to a smaller pulley and maybe that will solve the problem, of course you're going to have to retune for the smaller pulley but does that make any sense to anyone else? Increase the amount of air the s/c is putting into the cylinders at idle so the injectors won't have to dump so little fuel in eliminating the random misfire?
Also another thing...he said it throws the code at an idle or somewhere near a stop...now if what someone else said is correct about the air spiraling past the maf then the air filter would most likely be the cause...but if that isn't it then I would have to say the fuel trims are a little jacked up. just because you tune it to put that amount of fuel to the car doesn't mean that the factory system won't recognize that as irregular... Flash have you tried flashing your pcm with the custom 42s tune you said you had?
that makes no sense. if you are throwing a lean fuel trim code, why would you add MORE air to make the mixture leaner.
Smaller pulleys aren't the answer
Lean fuel trim means the computer is having to add more fuel because the o2 sensor reads a lack of fuel in the exhaust. If the ecu has to add more than a certain amt of fuel to correct the afr, it will trigger the code p0171.
Smaller pulleys aren't the answer
Lean fuel trim means the computer is having to add more fuel because the o2 sensor reads a lack of fuel in the exhaust. If the ecu has to add more than a certain amt of fuel to correct the afr, it will trigger the code p0171.
Last edited by djp89; 01-09-2009 at 02:15 AM. Reason: Automerged Doublepost