Fuel Trims maxed still
Nov 17, 2007 | 04:35 PM
#1
Thread Starter
Launching!
Joined: Apr 2005
Posts: 208
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From: Mesa, AZ
Fuel Trims maxed still
I was having issues with my fuel trims being peaked out at 25 for some time now and can not track it down. I did a vacuum test and it came back perfect on the gauge with no fluctuating or anything just a steady read of 19 which is dead center of the range it needs to be in for a healthy engine (according to my Manual). Next step I guess is to try and swap out the MAF and see whats up but anyone have any other idea's what is causing this. I keep bothering the same person on this issue so wanted to put this out there and maybe someone can help me as well. Intake is on and fine, no cracks or anything but air is getting in somehow and causing this somehow.
Anyone have a spare MAF that is local to the phoenix area??
Anyone have a spare MAF that is local to the phoenix area??
Last edited by fox_forma; Nov 17, 2007 at 04:42 PM.
Nov 17, 2007 | 10:04 PM
#2
Do you have any exhaust leaks? In particular at the header collectors on the flanges on the heads. That is an open spot for fresh air to enter the system. It will throw your o2's completely off like that too.
Nov 17, 2007 | 10:48 PM
#3
Thread Starter
Launching!
Joined: Apr 2005
Posts: 208
Likes: 0
From: Mesa, AZ
I never touched my head so i doubt it but I guess its possible but would a vacuum test show some sort of fluctuation when reading? In my manual it shows several problem solvers if the vacuum gauge does certain things like drop or raise during the test and mine held a flat steady reading.
Nov 19, 2007 | 09:54 PM
#5
A vacuum leak will usually not cause full trim adjustments. Usually a vacuum leak is managable, as far as the computer is concerned. It will correct it by a small percentage, not a whole lot.
An exhaust leak or faulty o2 sensors could be a cause.
An exhaust leak or faulty o2 sensors could be a cause.
Nov 19, 2007 | 10:37 PM
#6
unless a manifold gasket is bad....and these trucks are famous for the manifold gaskets failing.
Nov 20, 2007 | 07:27 AM
#7
His trims are maxed on both banks... not an exhaust issue...
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Nov 20, 2007 | 08:05 PM
#8
Thread Starter
Launching!
Joined: Apr 2005
Posts: 208
Likes: 0
From: Mesa, AZ
I figured you would pop on in Justin once again, I was trying to not bother you as much with this. Just cant figure it out, I hooked a vacuum gauge up and it read great with no fluctuation or anything. I did however change something today with my intake where the MAF mounts to the Volant box and it seems my truck is pulling harder in the mid range and up top now. Who knows, more logging will be done soon.
