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Working on a 2006 chevy 5.3L in a 79 Scout, I've checked all the wiring, swapped MAF sensors, fogged the intake, no leaks. what could I be missing the MAF code is intermittent, as well as the lean codes. LTFT go super positive when you touch the throttle, on a long trip it runs fine, but in stop and go traffic, it stumbles stalls and cant get out of its own way. Any thoughts?
We really need to see your tune file and a datalog so that we can help you.
If the LTFT's are going positive, then it's really lean. I'd typically start by checking fuel pressure, then checking the MAF and MAP sensors.
Very true.
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Its really just a stock tune with just the VATS deleted
I'm not sure if it's a problem with the location of your MAF, or a fuel delivery issue.
Let's try this, I disabled the MAF in your tune. Just load it and give it a try. If this doesn't fix the issue, you'll need to double check your fuel pressure when you have an opportunity.
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Thanks for your help. Had to download the new software.
Up loaded your SD tune, it ran better but it was still positive, not as much. It has around 65 PSi fuel pressure, the whole time idling and driving.
in tank fuel pump - Walbro Electric In-Tank Fuel Pumps GCA758-2, and corvette regulator.
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If you have a PCV tube in front of the MAF, move it to behind the MAF. Any air coming into the engine that hasn't passed through the MAF, is unmetered air and will cause fuel trim issues at part throttle and especially idle.
Wish it was that. The intake is filter, MAF, Alu. Tube, elbow, throttle body. No extra hoses.
Where is your PCV getting its fresh air from then?
its a truck intake. LM7
Hows your PCV system setup?
stock just like every other truck manifold. Passenger side to behind the throttle body, drivers side off the top of the manifold.
That last datalog looks much better. Try this one and see if it fixes the issue.
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Thanks for your Help.
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After F**king around with the tune and not getting anywhere ahead, I went back and trouble shot the po102 for the third time this time I found high resistance from MAF connector ground, to the block. Somehow the ground had backed out and was causing the problem... I think. How long does it take for the computer to reset itself for the proper fuel trims?
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You can manually reset them with the scanner. Special controls (next to DTC button up top), click the fuel tab, you?ll see the reset button on left side.
Ok that seems easy enough, how long will the computer take to relearn them or does that happen . Next question. Why would I have LTFT that don't change?
Worried if I give this car back to the guy and he has the same problems before it came here. All stock tune I would think it should run itself.
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It will start learning when it goes in to closed loop, once the vehicle reaches 131 deg. ECT...... if you are tuning, and clear the LTFT's, I always like to get rid of what I call false info.....so I will....
start scan
clear LTFT's
stop scan (getting rid of garbage LTFT data)
re-start scan (starting with fresh fuel trim data)
Are you trying to tune the MAF, or the VE side currently?
Did you notice you have a bit of knock retard around 2200rpms on your last log?
I'm not trying to tune it really just make it reliable for him to use as a daily driver and not have it stumble and fall on it face.
I didn't notice the knock. Was looking at LTFT