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328 ignition problem

Discussion in 'Technical Q&A' started by ctnbop, Oct 25, 2005.

  1. ctnbop

    ctnbop Rookie

    Oct 3, 2004
    10
    San Jose, CA
    Full Name:
    Canh Nguyen
    I've been chasing a poor running condition and have searched the archives. Any help (or point me to a thread that applies) would be great.

    I've had an 88 328 for 8 mos, 50K miles when I got it, 53K now. I have a great independent tech who is just too busy lately to help. When I first took delivery, he mentioned that he noticed a slight off-idle hesitation. He replaced a few plug extenders, I took it, and all was well.

    I drove it almost everyday for 6 mos. For the first few months, at cold start-up, RPMs would dip before going into high idle. Then about once a month it would not high idle. I would drive it very low on power with clicking from the fuel relay. It would go away after several minutes and run all day without further problems.

    This problem became weekly, then daily, which has made it undriveable. I have traced it to the entire front bank not firing (using a timing light), testing the individual leads plus the coil lead. It smells rich, so that makes sense.

    I switched coils, and it runs well. Thinking that it was a matter of poor connections, I returned the coils to their original positions and the poor running returns. It seems to me that all components are working, just that the combination of certain components together do not.

    I am mechanically inclined, enjoy doing the work, just don't have much time to go down the wrong path. Would greatly appreciate some advice.

    Thanks.
     
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  3. DGS

    DGS Four Time F1 World Champ
    Rossa Subscribed

    May 27, 2003
    41,988
    MidTN
    Full Name:
    DGS
    This may seem a bit obvious, but if it works okay with the coils switched, why not leave them that way?

    It could be that one of the coils is going, and one of the computer output triggers may be sharper than the other.

    But if it works, why fix it?

    Alas, most mechanics these days can't find a problem until it stops a car. Shop labor rates make tracking down an intermittant problem not cost-effective at professional shops.

    Short of getting a 'scope and doing a complete ignition system trace, it's probably easiest to swap coils, and wait for additional symptoms.

    But you might check that both banks have the same type of plugs. (Hotter on one bank?)
     
  4. KurtK328

    KurtK328 Formula Junior

    Mar 6, 2001
    347
    Villeneuve-Loubet, France
    Full Name:
    Kurt Kjelgaard
    New extenders and ignition wires usually cures all ignition problems.
    Make sure the cables are fixed in their holders to prevent excessive vibration.
     
  5. KurtK328

    KurtK328 Formula Junior

    Mar 6, 2001
    347
    Villeneuve-Loubet, France
    Full Name:
    Kurt Kjelgaard
    Sorry - substitute "all" with "many" in previous post
     
  6. ctnbop

    ctnbop Rookie

    Oct 3, 2004
    10
    San Jose, CA
    Full Name:
    Canh Nguyen
    I did think about leaving them switched since it does seem to cure the problem, but am looking for an underlying cause instead of a temporary fix. For example, if one coil is indeed going, but works because one computer output is stronger, what can I do about that? I figure with the age of the car, I should at this point go through all connections and check everything that a home mechanic can. Any other ideas?

    Thanks.
     
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  8. Mark 328

    Mark 328 Formula Junior

    Nov 6, 2003
    510
    Orange, Ca
    Full Name:
    Mark Foley
    You may want to swap-out the control modules on top of the coils.
    A lot of the coils and extender problems can be exacerbated by moisture. Does your car have more problems after you wash it? I rarely wash mine (use Mcguires Quick Detailer instead) because I don't like the idea of all that water running through the louvers onto the engine components.

    With my car, when I swapped-out the module for a friend there was a bad connection and one bank would not fire. Moved the plug around and it hasn't missed again. Be careful toughing wires near the coils--there is a lot of voltage.

    Another issue with the coil brackets is the ground--may want to try to run a supplemental ground. I thing there is even a spade plug on the coil brackets for this.

    Mark
     
  9. CliffBeer

    CliffBeer Formula 3

    Apr 3, 2005
    2,192
    Seattle, Washington
    Full Name:
    Cliff
    Some things worth checking (based upon the described symptoms) here are: a) the warm up regulator, b) the thermo time switch, and c) the fuse for the ECU (located in the trunk, on top of the relay, next to the Jetronic ECU). Do a search for these items and you'll find some diagnostic tests for each to determine proper (or not) functioning.
     
  10. mhm4223

    mhm4223 Rookie

    Nov 14, 2004
    12
    Perrineville, MJ
    Full Name:
    Michael Merkin
    I currently own a 1986 328 GTS and experienced the same problem after running the vehicle hard a Lime Rock one afternoon during a club event. I had no spark on 1/2 the engine and found the connection to one if the ignitors had a poor connection. Your problem probably disappeared because you had to unplug the ignitors to switch coils. Just cleaned and tighten the connector plug and you will hopefully eliminate the problem. To test the theory, just wiggle the connectors while the engine is running and see if your dead bank starts to fire again. Hope this helps.
     
  11. ctnbop

    ctnbop Rookie

    Oct 3, 2004
    10
    San Jose, CA
    Full Name:
    Canh Nguyen
    So I finally pinpointed this problem. It was indeed one of the wires to the front bank coil. The connector gap was too wide, so even though I'd sprayed contact cleaner on everything, it actually needed to be tightened. It was frustrating because I thought it was the main coil wire. When I wiggled the main coil wire, it would make the front bank fire. Turns out it was touching and moving the other wire which was the actual culprit. Add another case of poor electrical connections to the archives...

    Thanks everyone.
     
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  13. radioman

    radioman Karting
    BANNED

    Sep 25, 2004
    141
    UK
    Full Name:
    CHRIS
    nice one, glad you found it we can all benefit from these types of threads,
    i had a elecrtical prob almost the same and guess what?, contacts to wide somtime works and always when your looking for it.
     

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