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Another p0171 problem. I am running out of ideas and need help.Fuel trims high w idle

Hardonyomom

Hardonyomom

New member
I know that many have had this issue of pulling the powertrain system too lean (bank 1) before maybe my story is a little different.

First of all here are my current mods.
1.9 modded rockers, LS7 lifters
Ac delco iridium 41-104 plugs,new wires
SD Headers, no cat, stock exhaust , second 02 sensor delete from dhp tune. Never throws an o2 code.
zzp Lim, ported gen 3, Full size intercooler (2.5 inches) frozenboost Fmhe, Stock throttle body, hai
zzp modded fuel rail, 60 lb injectors with new o rings, No leaks
zzp mps, 3.4 pulley

Okay so im new to understanding the torque app but ive been getting better. What i am concerned with is that i have i have higher than normal fuel trims at idle

Here are my numbers

LTFT1- Highest value 16.4, Lowest value 2.3
STFT1- Highest value 20.3, Lowest value -5.5
My o2 1x1 highest value is .9
Knock retard is ZERO though

I have only driven the car for about 15-20 miles and the highest ive taken it to is 50ish mph But i did get close to 12 pounds of boost. I know that running fuel trims that high means im running lean at idle and the computer is having to throw at least 20 percent more fuel to compensate for something but i also know that when im driving the numbers go down and seem safe. The tune is off of a buddy with a similar setup that he had 42 lb injectors for and threw it on my car to get me going but i think he added 30 percent more fuel or something like that.

I know that everyone is going to say you have a vacuum leak but i have tried for quite some time to find one. All my lines are connected. No cracks. I sprayed brake cleaner with it running and i didnt hear the engine speed up or anything. I made sure when i put the supercharger onto the intercooler i used a felpro upper plenum gasket as my diagram and put rtv exactly where you are supposed to and torqued it within 20 mins.

My question is , does a p0171 code ALWAYS mean vacuum leak or could it be something else stupid like a fuel injector not being seated properly or bad o ring or harness or something like that? Would getting a proper tune get rid of the problem or is it for sure a vacuum leak?
 


I am having the same issue p0171 LTFT pegged at 16.4 and STFT pegged at ~20 these are some things to start with. So far the only thing I have done is replaced the fuel filter and replaced vac lines.
A lot of times, cleaning the MAF sensor and finding/fixing vacuum leaks fix the problem. If you're on a tight budget, start there, but that may not be the fix for certain.

So, possible solutions include:

  • Clean the MAF sensor. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
  • Inspect all vacuum and PCV hoses, replace/repair as required
  • Inspect all hoses and connections in the air intake system
  • Inspect and/or test the intake manifold gaskets for leakage
  • Check for a dirty fuel filter and proper fuel pressure
  • Ideally you'll want to monitor short and long term fuel trims using an advanced scan tool
  • If you have access, you may want to run a smoke test.
​
http://www.obd-codes.com/p0171
 
20141113_160827.jpg


I did Rtv this correctly right??? I do NOT want to redo it again.
 
Soooo, i found my vacuum leak. The good news is that i have no leaks coming from where i rtv'd the supercharger :) and i have no leaks from vacuum lines :) Where do i have a vacuum leak? Its from heater core tube where i was supposed to cake on the rtv to put the new intercooler back together. I guess i didnt use enough. Well, that should be an easy fix. :)
 


I started to work on mine, took my maf out and cleaned it, it was really really dirty. Next up spray carb cleaner around to find a vac leak.

Sent from my Galaxy Far Far Away
 
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