06 roush runs extremely rich/ barely starts

Discussion in '2005+ Mustang GT 4.6L Tech' started by Andrey Sidorov, Sep 27, 2020.

  1. Andrey Sidorov

    Andrey Sidorov Member

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    Hey guys, nice to meet you all, i have an 06 stage 1 roush with procharger on it
    Recently my alternator went out and after i replaced it with sr performance one i started to have issues explained below (not sure if these are related with alt swap tho).

    Car runs dummy rich, 10.1 afr on wideband, smoke on startup and gas smell. Both front o2 throw codes and show 0.9 volts when at idle or when accelerating which indicates stupid rich condition. When i put the car in a limp mode by removing maf and starting it (failsafe tune) car rans normal (as it can in limp) and o2 shows 0.1-0.5 volts which is absolutely normal range and car doesnt run rich. That makes me think that o2 are actually working properly and something else makes the car dump so much gas. Also when you drive and stop at the light in neutral rpms drop to like 500 and go back up to 850
    What you guys think it could be? Tune went to crap?

    What i did so far:
    -New plugs yesterday
    -Cleaned maf
    -Cleaned throttle body

    Also car doesnt start normally, smokes crazy (gas) with gas smell and bogs down , in limp mode starts fine
     
    Last edited: Sep 27, 2020
  2. nawagner

    nawagner forum member

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    Double check all vacuum lines and any plugs. Look for any cracks or holes. It is sucking air somewhere. I had a plug on one of my supercharger ports that had deteriorated enough to leak. I know people claim their tunes went to crap, they don’t. It’s a program it can’t change unless you change it or the computer goes completely bad. The things that do change on their own, mechanical issues. And they change by breaking.
     
  3. Andrey Sidorov

    Andrey Sidorov Member

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    I looked at everything and saw no vaccum leaks, I might have to do smoke test tho. Even considering that , wouldn't vaccum leak make it run lean and not rich ?, Also of there would be a leak why would car hold vaccum at 39 as it should in fail safe mode ? , Also a huge detail I forgot to mention , car holds vaccum in limp mode but in normal mode shows boost at idle on vac gauge in torque app, that makes zero sense, why it's on boost at idle . Procharger boost gauge is at 0 at idle like it should be
     
  4. Pentalab

    Pentalab forum member

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    That's almost like your Procharger bypass valve is stuck..closed. It should be showing -20 hg vac on idle.
     
    crjackson likes this.
  5. Andrey Sidorov

    Andrey Sidorov Member

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    Thank you , will take a look cause that makes sense. Car runs in boost at idle instead of vaccum with maf in but in limp it holds vaccum at 39 which is weird
     
  6. nawagner

    nawagner forum member

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    Depends on where the leak is. I’ve had it do both. Sounds like you found the issue with the bypass valve.
     
  7. Andrey Sidorov

    Andrey Sidorov Member

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    Bypass was functioning well, I cleaned injectors at the shop and put new oem tps in cause I thought it might have to do with it , now car starts in limp mode all the time with low voltage code from maf, which I will check next, maybe something with a harness , cause maf itself is new (2 months)
     
  8. Andrey Sidorov

    Andrey Sidorov Member

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    Still have the problem, new bypass valve didnt solve the issue, can it be the IAT sensor by any chance cause it was showing some weird temps?
     
  9. golkhl

    golkhl forum member

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    All problems started after the new alternator? Did you do the install? Double check all connections and grounds first, don’t rule out a bad alternator(aftermarket alternators are hit or miss), but I think your problem lies within whatever circuit runs the alternator.

    I am a rookie(at best) with automotive electrical trouble shooting and diagnostics, but have spent a ton of research time lately trying to get my 94 project running.
     
  10. nawagner

    nawagner forum member

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    IAT sensor could cause the issue. You can check the IAT by measuring the resistance while using a hair dryer to heat it up. Resistance should change with change in temperature. You can also measure the voltage across it while plugged in and ignition turned to on, not running, and again use a hair dryer to change the temp of the sensor. Should read between 0-5VDC. I think the IAT is integrated with the MAF so you’ll need to find the pinout for which wires are the IAT.
     
  11. Juice

    Juice forum member

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    I dont belive that data from Torque is accurate. 0 is not boost, and -39 is not possible. Max possible vacuum is -29.x.

    What does Torque report for actual MAF flow and load?
     
  12. Andrey Sidorov

    Andrey Sidorov Member

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    I mistyped badly in there ahhaah, it shows -26.9 of vaccum in limp mode , here are some pics of maf reading and other things with maf plugged so in regular mode at idle

    IMG_20200927_193423.jpg

    IMG_20200927_193415.jpg

    IMG_20200927_192322.jpg

    IMG_20200927_192404.jpg

    IMG_20200927_192311.jpg
     
  13. Andrey Sidorov

    Andrey Sidorov Member

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    Thanks so much for the suggestion, I actually have a relocation kit coming from maf to the actual intake , will do it and will see if it does anything, cause people say when you run a blower the inmaf iat will do weird things
     
  14. Andrey Sidorov

    Andrey Sidorov Member

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    Pretty much yeah after the swap, I quadruple checked everything even reinstalled it fully, of nothing else helps including a new tune, I will buy the oem unit and will swap it, but those just don't hold the power, I ran through two
     
  15. Juice

    Juice forum member

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    What does Torque show with the maf sensor unplugged?
    11+ G/second seems high for idle IIRC, Im assuming that is plugged in.
     
  16. explict

    explict Heavy Metal S197 Team Member

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    Do you have an update for this?
     
  17. Pentalab

    Pentalab forum member

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    On my small Roush M90, the iat sensor is relocated to the aluminum intake manifold. That's after the intercooler. There is no way the iat sensor would function correctly in the stock location. In stock location, the iat temps will be a lot lower vs the intake manifold.
     
  18. scarsblonded

    scarsblonded Junior Member

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    was this ever fixed??


    Sent from my iPhone using Tapatalk
     
  19. scarsblonded

    scarsblonded Junior Member

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    got the same problem both o2 stuck rich


    Sent from my iPhone using Tapatalk
     
  20. scarsblonded

    scarsblonded Junior Member

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    buddy?


    Sent from my iPhone using Tapatalk
     
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