Mechanic Said I Have Bad Wiring Harness On Engine?

Discussion in 'SN95 4.6L Mustang Tech' started by Miller220, Jul 9, 2014.


  1. Miller220

    Miller220 Member

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    I had issues with my car a while back, and I'm finally getting it out for the summer and was curious. My old mechanic (he was awefully shady, did some shady work) said that I was having issues with the wiring harness on my engine. I'll be honest, I'm no mechanic, however, I'll assume he is talking about my wires going to the coils? For what its worth, I've had my coils redone because I was having issues before. My engine will still tremor once in a while, and he (ex mechanic) said that one of my cylinders wasn't firing reliably. Has anyone had any experience with this, or anything like it?
     
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  2. 84Ttop

    84Ttop They make new pistons every day, so why worry?
    SN Certified Technician Mod Dude

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    Does a check engine light accompany the tremor? Does the car otherwise run fine or are there other problems that you have noticed?
    Lets forget anything that the so called mechanic has told you prior and start from square one.
     
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  3. Gearbanger 101

    Gearbanger 101 Straight Outta Locash
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    When does this tremor occur? At idle, in gear, while driving, under load, while moving, in neutral?

    More details please?

    Have you run the engine for codes? A cylinder misfire usually shows up on a code scan.
     
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  4. Miller220

    Miller220 Member

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    The tremor occurs at idle. The alternator died, and I'm replacing that tomorrow. In the past, I've had issues with misfires, however I haven't checked to see if its throwing any cides recently. The car alternator died in mid December, so I'll get it up and running and report back with my findings. If I am still having issues with misfires, what could cause that assuming I've had the coils and plugs done within the past 2 years?
     
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  5. Gearbanger 101

    Gearbanger 101 Straight Outta Locash
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    What condition is your engine balancer in? A balancer on its way out will give you a bit of a wobble at idle.
     
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  6. Mattstang04

    Mattstang04 Active Member

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    A bad alternator can make these cars run like poo.
     
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  7. Nightfire

    Nightfire Mustang Master

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    I once had a bad misfire, VERY noticeable at idle. It turned out to be fouled up spark plugs. When was the last time you changed your plugs?
     
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  8. Miller220

    Miller220 Member

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    I didn't even know than an engine balancer was a thing. How would I check it? My alternator should be here soon! I'm pumped. Other than that, I'm 80% sure they were done when my coils were done a few years ago.
     
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  9. Miller220

    Miller220 Member

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    Ok, Update! So I installed my new alternator + extra wire, and turns out that it actually runs AND the weird vibrations at idle are no longer there. However, it's been replaced with a new problems (woo money pit!) namely the fact that it'll idle just weird. Almost too slow? Or too low, I'm not sure how to describe it. The engine almost Lopes..like I've got some cams. Boy do I wish. Any one have an idea what I can do before I take it into a shop?
     
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  10. 84Ttop

    84Ttop They make new pistons every day, so why worry?
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    With the battery disconnected for a long period it is possible for the car to need to learn the idle again.. I would put some miles on it first to see if it clears up
     
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  11. 1987stangman

    1987stangman Member

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    Took the wod right out of my mouth. I acually had tbat issue in my old 96' GT. Car sat for a long time, maybe a month on jackstands in the garage because i was doing exh and lowering springs. Whe. I got done with the car i reconnected the baterry and the idle was exactly as you described bjt went after after a good drive.
     
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  12. Miller220

    Miller220 Member

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    I have put some miles on it, idle hasn't cleared up, so I'll disconnect the battery to let the car relearn how to idle. Next up is it feels like the car is losing power for a split second (and I'll have this feeling several times throughout the entire range of RPM, in all gears, at all speeds) when I punch it. The best thing that I have to compare it to is a few years ago, when I first got the car, a couple coils went bad and weren't firing reliably. At the rate I'm going, I'll say screw the mechanic, because its already been into the shop twice for issues with Something electrical on top of the engine.

    Long story short, the car runs, my battery is no longer getting drained. I won't worry too much about the idle until I run it with the battery disconnected. Now I have what feels like power loss or a hesitation. Is that also something that could be caused by the cars computer not being familiar/me not having done the proper procedures..or is there something else I should be worried about besides doing spark plugs next week.
     
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