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Thread: 408 Issues

  1. #1

    Default 408 Issues

    Got the new motor fired yesterday and seemed to run ok. Went and got fuel sync set and drove around to break it in. Towards the end of the day it threw a couple codes, po172 and po351. po351 I understand is because I don't have a tach adapter on my MSD box.

    Got up this morning and fired it up and it was running like shit, very rich like 11.7 at idle. Stunk the garage up and fouled the plugs. My base tune is closed loop and Sean said we may have to go with open loop tuning. That's all good but why the hell would it run ok in closed loop one day and the next morning run pig rich.

    Any thoughts, aside from a possible tuning issue, on what to check? po351 points towards the coil so could that indicate a problem with the coil other than not having a tach adapter?
    Last edited by mikset; 04-08-2012 at 05:06 AM.
    408, HiPoTek, FRP Tuning, Martin Saine 46re
    12.33 @ 110
    2018 Renegade Raceway Summit Series Sportsman Champion

  2. #2

    Senior Member

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    Possible vacuum or exhaust leak is where I would look first.
    -Ryan


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  3. #3



    RTchas's Avatar
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    Maybe it's an email tune gone wrong? I had that on an email tune I got the file and it was corrupt, truck ran fine then didnt


    00 FR RC Dakota R/T Turbo 11.56@118

    99 Amethyst RC Dakota R/T 1-170 13.84@98

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  4. #4

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    I'm beginning to think it's either a stuck injector or a bad fuel pressure regulator. This thing starts dumping fuel like a bastard as soon as it starts.
    408, HiPoTek, FRP Tuning, Martin Saine 46re
    12.33 @ 110
    2018 Renegade Raceway Summit Series Sportsman Champion

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    Glad to hear you got her running, Mike! While diagnosing mine I thought it was dumping fuel too. I had spark at the plugs, so thought I had everything for ignition. It turned out the coil was indeed bad! If you have a spare coil, you might throw it on just for shits-n-giggles! LOL That's how I cured mine.

    Quote Originally Posted by mikset View Post
    I'm beginning to think it's either a stuck injector or a bad fuel pressure regulator. This thing starts dumping fuel like a bastard as soon as it starts.
    99 DA CC R/T
    13.97@100 w/modded kegger & ported TB
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    10:8-1 .30 over forged bottom end
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  6. #6

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    Quote Originally Posted by 99dart View Post
    Glad to hear you got her running, Mike! While diagnosing mine I thought it was dumping fuel too. I had spark at the plugs, so thought I had everything for ignition. It turned out the coil was indeed bad! If you have a spare coil, you might throw it on just for shits-n-giggles! LOL That's how I cured mine.
    Yeah, I had that thought too Pat. It's a brand new blaster coil but it would sure be worth a shot. I'll throw my old accel back on and see if it helps.
    408, HiPoTek, FRP Tuning, Martin Saine 46re
    12.33 @ 110
    2018 Renegade Raceway Summit Series Sportsman Champion

  7. #7

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    Coil didn't make any difference. I also bypassed the 6a just to check it.

    Sean sent me a test tune, he pulled 15% fuel. Helped a little. A/F Was 11.7 at idle now it's around 12.5.

    How go you check for a stuck injector if it's stuck open?
    408, HiPoTek, FRP Tuning, Martin Saine 46re
    12.33 @ 110
    2018 Renegade Raceway Summit Series Sportsman Champion

  8. #8
    blackknight's Avatar
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    well the 172, means it was running too rich! but you have it running now its all the computer relearning and tuning issue!

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