Newbie tuning saga of my LS Jeep TJ

[jeeper]

What does a spark plug look like on the internal white porcelain at the tip? It should be bone white if it is as lean as you think it is?
Rick

I will pull a couple plugs today. At least one from each side.

I do have a bluetooth OBD scanner. I will try it today to see what it will show for free. Otherwise I was thinking about buying Torque. Would that work? I can also hook up my V2 and see in real time what is happening on my computer I think.

I am assuming you have a 5 wire Delphi MAF? Please tell me it is NOT mounted directly to the throttle body? If the ducting and pcv system is hooked up correctly, a stock 5.3L engine will move about 225 grams per sec through the MAF at ~5000 WOT. If it is substantially lower than this, the MAF is bad, quite common. The gm/sec at warm idle neutral/park with a stock 5.3L should be ~6 and at 2500rpm in neutral/park it should be ~23-25.

If you need one, do NOT buy a rebuilt/reman MAF, they can be worse right out of the box, even AcDelco reman.
DELPHI AF10043 is usually reasonable priced.

It is a stock GM MAF. On the grounds that I might incriminate myself I probably shouldn't tell you I did mount the MAF directly to the throttle body. I'm assuming now that it's a bad idea? Is it a bad idea because of reaction time? Or maybe the air temperature is off because of it? I will relocate it if needed. I will also try testing it today when I'm looking at fuel trims.

[dave w]

The information below if from the EFI Live Tutorial section. It's a good plan to copy / paste the High Octane tables into the Low Octane tables when going MAFLess without "Boost".

dave w

Custom OS and 2/3 Bar Tutorial EFILive V7 Tuning
Tool




Going MAFless
When fitting a 2 or 3-bar MAP sensor you must disable the MAF sensor. It is possible to leave the
MAF sensor in place. This will need to be done on the 85mm MAF as the Intake Temp Sensor is located
in the MAF housing. Alternatively, you could relocate the IAT using on older style IAT sensor.
Even with the MAF still in place, the PCM must be forced to ignore the MAF signal.
To disable the MAF sensor:
Set the Engine Diagnostics->Engine Diagnostics->MAF->Parameters:
• {C2901} MAF High Frequency Fail 1: 1Hz
• {C2902} MAF High Frequency Fail 2: 1Hz
If calibration {C2902} is not available in the operating system that you are using, then ignore
this step.
• {C2903} MAF High Frequency Fail Limit: 1
• {C2907} MAF Test Min Engine Speed: 300 RPM
• {C2908} MAF Test Min Run Time: 0.1 seconds

Set the Engine Diagnostics->Engine DTC processing Enablers:
• P0101 ‘C’ Non Emissions
• P0102 ‘C’ Non Emissions
• P0103 ‘C’ Non Emissions

Set the Engine Diagnostics->Engine DTC MIL Enablers:
• P0101 ‘No MIL’
• P0102 ‘No MIL’
• P0103 ‘No MIL’


When going MAFless and/or boosted on vehicles with Electronic Throttle Control, you will most
likely need to increase {C6101} ETC Predicted Airflow, by significant amounts to stop the PCM going
into reduced power mode.

Set the
Transmission Diagnostics->Transmission DTC Fault Max Pressure Enablers
• P0101 ‘No’
• P0102 ‘No’
• P0103 ‘No’

Set the Transmission Diagnostics->Transmission Failsafe Enablers:
• Set all airflow related enablers to ‘No’ to prevent the transmission from going into failsafe
mode due to the MAF being disabled.


































































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[jeeper]

I spent a few minutes and removed a couple spark plugs. The tips were light tan but the plugs were not new when I started this swap. The engine had these plugs in it when I swapped it in so I don't know if it really matters much what they look like now.

I took another short video today.


Some of the gauges I selected don't appear to be working but it does show short term fuel trims.

[B52Bombardier1]

Hello,

I have Torque but I'm not much of a fan because it is incomplete on parameter IDs for me. Yet it did show that your O2 sensors are working and your fuel trim is not maxed out. I've seen my LTFT maxed out at +25 due to chaotic air at the MAF screen until I changed out the tubing headed into the throttle body. Now my fuel trim values look much like yours. You definitely are not outpacing what your fuel injectors can handle.

So I'm still puzzled here but think the advice given for a bad MAF might still be correct. If you don't want to pay full price for a new MAF, go to the junk yard and buy another one or two for cheap. They make great diagnostic tools in situations like this and if they work well, now you have spares.

Edit: It is odd that your Bank 1 and Bank 2 fuel trims mimic each other so closely - almost exact copies of each other. Mine vary a good amount between the two sides of the engine but are generally under +8 for LTFT and less than +5 for STFT.

Rick

[jeeper]

That wasn't actually Torque. It didn't seem to have a lot of PIDs. I ended up using OBDLink.

I'm going through the tune now and failing out the MAF to test. I'll report after I have tested it.

[jeeper]

Thanks dave w. I didn't really understand your post until B52Bombardier1 mentioned what it meant...

I set the MAF to 1Hz and tried it. It seems the MAF is causing my problem.
So is it common for the MAF to fail gradually?

Short video confirming it is not great but better with the MAF disabled. It doesn't idle as good but it is way less lean.

[dave w]

On most operating systems, when the MAF is set to 1Hz the low octane table is default. Try copy / paste high octane tables into low octane tables.

dave w