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Thread: Newbie tuning saga of my LS Jeep TJ

  1. #16
    Fuel Injected!
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    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?

    Fuel trim? Long Term Fuel Trim (LTFT) and Short Term Fuel Trim (STFT) - these are indications from your PCM that tell you how much your fuel injectors are struggling to keep the mixture close to a stoichimetric 14.7 to 1 ratio. Any of the good Android or IOS OBD 2 code readers can tell you these values. My favorites here using Bluetooth on Android are OBDLink, MotorData OBD, and OBD Fusion. All are very inexpensive or free though to gain access to the extended parameter ID's might cost you 5-10 bucks.

    Rick
    1970 Chevy El Camino, LM7 Engine, 4L60E - Two 896 and two 0411 PCM's

  2. #17
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    The engine is completely stock. I did mount the MAF directly to the intake and it has a high flow air cleaner in a cold air intake setup.
    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.
    -Carl

  3. #18
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    Quote Originally Posted by B52Bombardier1 View Post
    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.



    Quote Originally Posted by In-Tech View Post
    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.

  4. #19
    Super Moderator dave w's Avatar
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    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.


































































    support@efilive.com - 15 -
    www.efilive.com

  5. #20
    Fuel Injected!
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    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.

  6. #21
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    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
    Last edited by B52Bombardier1; 1 Week Ago at 12:49 AM. Reason: additional information
    1970 Chevy El Camino, LM7 Engine, 4L60E - Two 896 and two 0411 PCM's

  7. #22
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    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.

  8. #23
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    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.

  9. #24
    Super Moderator dave w's Avatar
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    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

  10. #25
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    So I did a couple things this evening.

    I started off by taking it for a test drive to watch the AFR under a real load. At WOT it still goes about 15 AFR which is a bit lean. I decided I'd adjust the octane tables next.

    I copied (with labels) and pasted (with labels) the high octane table into the low octane table and did a cal-flash. I tested it in the driveway but didn't road test it yet. It doesn't help the idle at all but I haven't tested it for power on the road.

    I then decided I'd relocate the MAF from the throttle body to just after the air filter. I also borrowed the MAF from my sons TJ that I installed a 5.3 into (his Jeep isn't done yet). I reloaded my original tune and tried that revving it in the driveway. It still runs lean that way but not as bad as my MAF was causing. It would sometimes make it to 16 AFR but wouldn't stay there for long.

    At this point I'm wondering if I'm actually ready to try tuning it?

  11. #26
    Fuel Injected! steveo's Avatar
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    no

    15:1 at wot is really really lean

    a stock gm calibration would be 13:1 or richer

    thats a pretty massive fueling error

    dont tune it

    one more time

    a stock engine with a stock tune will maintain a good AFR under all conditions unless something is broken

    in fact except for a very small performance edge and tuning out the emissions stuff of accessories you aren’t using, you shouldn’t have to tune it at all

  12. #27
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    Hello,

    I agree with Steveo. Unless you have swapped in a radical cam, changed the intake manifold to something that flows a lot better or put in a different type of fuel injector, you should not have to make tuning types of changes to your operating system. The 5.3 in my El Camino got a set of headers and that change did not require anything to be changed in the OS. The PCM is quite adaptive, within reason.

    From what you have described about your Jeep so far, it should not need anything changed from a performance standpoint. Maybe a slight change to Power Enrichment but I would not worry about that now for the little benefit that it brings to performance. Most of your efforts will consist of killing off MIL / CEL things like EVAP, EGR, catalyst overheat, rear O2 sensors, etc. I also have a long list of DTC's that get turned off.

    Rick
    1970 Chevy El Camino, LM7 Engine, 4L60E - Two 896 and two 0411 PCM's

  13. #28
    Super Moderator dave w's Avatar
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    I'm wondering if the injector programming is correct?

    dave w

    FJ315_Connector__ra_p.jpg

    FJ502_Other__ra_p.jpg

  14. #29
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    I appreciate you guys trying to help me sort this out. I also appreciate you being patient with me. I know what it's like trying to help someone who you're sure is dense... And I am sometimes dense.. thick skull.

    I really don't think it's a hardware problem right now. Especially after seeing such a marked improvement simply by failing out the MAF.

    I think maybe I should "start over" with a stock OS.

    I will look for my "original" OS that came on the computer I got with the engine. If I saved it, I can compare it to what I loaded into the pcm to convert it to a manual transmission OS. My problem is the original laptop I used to program it died and I don't know if I got everything off it. I can probably find a stock 2000 Silverado OS online somewhere if I don't have my original.

    Does that sound like a reasonable next move?

  15. #30
    Super Moderator dave w's Avatar
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    The 12212156 OS is a good foundation to build on.

    There are two types of injectors used on the 5.3 Liter, with very different injector parameters programmed into the flash, see pictures in the above post. Injector parameters are very important. Using the wrong injector parameters will cause ENORMOUS HEADACHES and possibly create dozens of posts about "what is wrong." A classic example of using the wrong injector parameters occurs when a LS1 5.7 intake has been installed on a 5.3, but the 5.3 flash was not updated with LS1 5.7 injector parameters.

    There are a couple different strategies for building a custom flash. Start with a 5.3 flash and segment swap in the manual trans section or start with manual 4.8 / 6.0 and segment swap in the 5.3 section. I've tried both strategies, with varying success. Ultimately, the most successful flash "for me" started with a 4.8 manual flash, and updated with "hand picked" not segment swapped 5.3 parameters.

    dave w

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