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Thread: HEP root failure

  1. #1
    Supporting Member Turbo Mopar Contributor
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    HEP root failure

    any one with ideas on the root cause of HEP failure?

    I was thinking either bad HE sensor or faulty wiring.

    I have Shadow88's faulty HEP so I will give it a test while my son and I are building MPSciLink boards
    Regards,
    Miles

    DD '87 Sundance T1, SLH with rear disks
    '87 CSX #432 2.5 CB TII, SLH

  2. #2
    Rhymes with tortoise. Turbo Mopar Staff cordes's Avatar
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    Re: HEP root failure

    My hypothesis is that if people leave the wiring loose, then the failure will come from broken wiring at the HEP. I've lost one or two of them due to an intermittent failure in my black Omni back when. The wiring harness problems I had with it are near legendary, and that's what I've attributed it to.

    Frankly, for all the bad mouthing HEPs, and especially aftermarket units, I've only had 2-3 of them fail. One was a JY take off which still lasted a couple years. I think I get about 150,000mi out of one if you average it out. Not bad IMO.

  3. #3
    Supporting Member Turbo Mopar Contributor
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    Re: HEP root failure

    Quote Originally Posted by cordes View Post
    My hypothesis is that if people leave the wiring loose, then the failure will come from broken wiring at the HEP. I've lost one or two of them due to an intermittent failure in my black Omni back when. The wiring harness problems I had with it are near legendary, and that's what I've attributed it to.

    Frankly, for all the bad mouthing HEPs, and especially aftermarket units, I've only had 2-3 of them fail. One was a JY take off which still lasted a couple years. I think I get about 150,000mi out of one if you average it out. Not bad IMO.
    Thanks, this is my primary thought as well.
    Regards,
    Miles

    DD '87 Sundance T1, SLH with rear disks
    '87 CSX #432 2.5 CB TII, SLH

  4. #4
    turbo addict
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    Re: HEP root failure

    the usual fail is the wires
    little fine finkie way too small wires
    and the thick isolation around them that gets hard with time.. not that it doesn't already start out hard

    the isolation causes the wires to streach until they finally break
    usually right where the wires go into the hep or plugs ..where every thing can flex

    I found the fix at canadian tire back in the mid 90's

    they sold a hep with wires that were larger gauge and had a SOFT rubber isolation much like a soft lamp cord
    there were two grooves in the rubber isolation -between each strand of wire

    I found one at the scrapyard one day and scooped it
    I've since used that exact same hep in every one of my cars since

    5-6 cars between say 93 and 2001
    and , my blue turbo z that used to be at the bottom of my posts on td .. that car sat for 2001-2016 until I scraped it
    with that same hep in it
    my new charger needed a hep when I first got it two years ago
    guess what's in THAT distributor too ...lol

    whenever I got a new car I'd install that hep , my accel air filter that's way way better than a K&N
    and a second external voltage regulator , ready to be plunged in when needed

    the filter is discontinued - there's a pic in my album on the other site with the part number
    it is worth google searching for one
    it took a while but I found another (pictured) and it gives a definite improvement in throttle feel , at least
    Last edited by Dr. Johny Dodge; 12-25-2017 at 06:18 PM.

  5. #5
    Super Moderator Turbo Mopar Staff 135sohc's Avatar
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    Re: HEP root failure

    I drove around with an HEP that was cracked/broken and missing the top half for a number of years. Electrically it still worked and I never thought anything of it. The OEM wiring harness has a large clip on it near the HEP plugs that is intended to hold them and not be flopping around. Between that clip becoming brittle and breaking off, the tape coming loose and things falling off and someone who just doesnt give a **** and let everything flop around instead of restowing/redressing the wires back into the bundle..
    1994 Shadow Sedan. 2.2 N/A, A568 400,000 miles. "the science experiment"
    1987 Shelby CSX #418. Long term rebuild and restore ?

  6. #6
    turbo addict
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    Re: HEP root failure

    lol
    handle the hep wires like glass strands and the o-e vacuum lines like glass tubing and one "should" be ok

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