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Thread: Rich Idle with fan running lean with out

  1. #1
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    Default Rich Idle with fan running lean with out

    As the title says engine runs rich with cooling fans on, when they switch off it goes super lean. Tried SD with MAF disable and no change. Turned on short terms and it corrects for each scenario. You can add fuel to the VE and MAF table in those areas and there is no change in AFR. Im lost, have never seen this. This is a 5.3 216/220 /550/.550 on 112. 50lb Flex fuel injectors at 40-45 PSI rail pressure. Fast 92mm TB LS2 Intake shorty headers in a XJ cherokee.
    I have posted the tune and log. At the end of the log the cooling fans turn on then goes rich. Ideas?
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    Last edited by kostelacd69; June 14th, 2017 at 03:00 PM.

  2. #2
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    What does voltage due? Also, why is the rail pressure so low? If you used GM injector data everything is based on higher pressure.................

    On second look. I compared your injector data to the injectors you said you used. I'd double check your injector setup.
    Last edited by ProperTuningOG; June 14th, 2017 at 04:15 PM.

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    Battery voltage stays at 13.5. Fuel pressure also stays steady. Pressure is low because I'm using the stock jeep internal regulator. Injectors data came from the truck that the injectors did. They 50lb @ 58 psi. Just lowered the flow rates by that percentage. Also I have tried running a 2002 camaro OS and a truck OS with no change. Changed all the injector back to stock 02 camaro and Silverado. No change. Played injector flow rates up and down. No change. And when I say no change it still did it. Maybe differ aft numbers but symptoms were still the same

  4. #4
    Joe (Moderator) joecar's Avatar
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    Where is your air cleaner inlet located (does MAF see fan air blowing on it)...?

    Post pic of engine bay.

    ~ posted by phone ~

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    Here is a picture of the bay. The Rad and Fan are offset to the passenger side and the filter is in the driver side corner. I also tried in speed density with the MAF disabled (c2901 set the fail in the tune to 1HZ) and still does it.
    Thanks
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    Last edited by kostelacd69; June 15th, 2017 at 12:14 AM.

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    Stupid ass Iphone. Cant get the photo up right sorry
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    Last edited by kostelacd69; June 15th, 2017 at 12:11 AM.

  7. #7
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    Now fuel trims wont turn back on.
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    Injector data is much more than flow rates. The file up has 1 part changed and the rest not.

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    Quote Originally Posted by Team208Motorsports View Post
    Injector data is much more than flow rates. The file up has 1 part changed and the rest not.
    Very true, I originally had the other 4 tables changed for the 50# injectors but in a attempt to get back to a stock tune as possible i change almost everything i could back to stock to see if it was something i did. Thats why only flow rate is changed in the above tune. Once I figure out the problem now with short terms not working i can get back to the rest of the tune.

    I am going to cut apart the intake tube and add a air straightener to see if that help with the rich/lean condition. Like JoeCar said maybe some fan air is working its way over there.

  10. #10
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    Update, after thinking about failing the MAF by setting the fail number to 1HZ I tried unplugging the MAF all together. After that the engine stopped doing its lean and rich idle. So that says the MAF is seeing more turbulent air from the fans (it wasn't very steady to begin. 5.3 + cam + 4 inch intake tube= slow crappy air), so I cut the intake tube apart, added a air straightener and its fixed! Now on to the short terms. This computer was reading long and short terms, it was also reading Park and Neutral from the switch. It now doesn't do any of those things now. In fact the o2 voltages are way off all the time on both sides regardless of AFR and rpm. Did a full reflash of the original tune i started with that i knew it all worked on and still nothing. Guessing the PCM is a POS. Going through the process of getting another one.

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