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Boxer questions.....

Discussion in 'Technical Q&A' started by jrg1, Mar 26, 2005.

  1. jrg1

    jrg1 Karting

    Nov 20, 2003
    60
    nyc
    Full Name:
    john
    Hi everybody......So my '83 bbi has been running like a champ, fresh from a major service (belts, seals, distributor, etc, etc.), and last night I'm on the Garden State Parkway, stop for gas, start up, head back on the highway, and the car has absolutely no power - feels like its running on about two cylinders. Oil pressure and temps are all fine, but it just won't go. And then it starts backfiring (unburnt fuel igniting???), so I pull over and shut it down and call a flat-bed. As an experiment, I started it, and checked the exhausts, and sure enough only the right side appeared to be emmitting exhaust, and then about ten seconds later, the left side started up, but i could "see it" missing. So what do you guys think? I did have an episode before the major, where it seemed as though a bank had shut down, and belive it or not, when I turned the headlights on and off (why I thought to do that, I have no idea) the other bank came back to life.....Secondly, I have a feeling I could have limped home, but not wanting to take chances I called the tow-truck......for future reference, can you actually drive a car on one bank, with a backfire, without doing serious harm to the engine? Thanks for your help........John
    Btw, car has the original euro-spec exhaust, no cats (sorry, Frank), and all names in this missive have been changed to protect the guilty.
     
  2. henryk

    henryk Formula Junior

    Dec 9, 2003
    479
    Door County, WI
    Sounds like a fuel pump problem........the Boxer has two fuel pumps, each with it's own fuse. Each pump supplies fuel to a bank of cylinders. Check the two FP fuses........in the glove box area.
     
  3. jrg1

    jrg1 Karting

    Nov 20, 2003
    60
    nyc
    Full Name:
    john
    Henryk, am I wrong in assuming that if the fuse blew the bank would completely shut down, rather than just miss? I ask this because it seemed to be an intermittent problem......surging, lumpy idle, etc.....thx
     
  4. coachi

    coachi Formula 3

    May 1, 2002
    2,108
    SC USA
    I have had much the same problems in the past with my 83 Boxer...and after many months and many many dollars, it turned out to be the alternators...get them rebuilt, if this was not done when the engine was out...you'll save 10 grand at least, because I had all sorts of things replaced, both fuel pumps, both filters, the dinoplex, auxiliary valves, had the fuel distributors rebuilt three times, and on and on...I forget what else was done. At the end, it was the alternators. They are horrible...and need serious attention...my 2 cents worth. I even had the tanks out, had them cleaned, refinished, etc...wished I had known about the alternators first...
     
  5. jselevan

    jselevan Formula 3

    Nov 2, 2003
    1,849
    John, HenryK is, as usual, correct in pointing out fuel pumps. You are correct in asking whether this might be intermittent.

    The fuses are frequently the culprit. Furthermore, the fuse block may be melted, providing a loose fit for the fuse and consequent intermittent contact. I would first check the pump fuses and contacts for tightness.

    However, the second Corollary to Murphy's Law is that 1) Murphy was an optimist, and 2) the likelihood of identifying and attributing a problem to a particular system is inversely related to how easy it is to fix that system. Fuses are easy to fix.

    Jim S.
     
  6. jrg1

    jrg1 Karting

    Nov 20, 2003
    60
    nyc
    Full Name:
    john
    Thanks guys for your input......I actually have two new fuel pumps and a new fuse box from a previous service a couple of years ago.....As for the alternators, I'll have to check my "trail of tears".....I do love this car though, this is the first time it has left me stranded in three years/8k miles......and I probably could have made it home.....thx again everyone
     
  7. Sean F.

    Sean F. F1 Rookie

    Feb 4, 2003
    3,000
    Kansas
    Full Name:
    Sean F
    If it's a new OEM fuse box that does not mean the fuse will not be the problem. It's an each check so go there first.
     
  8. GaryReed

    GaryReed F1 Rookie

    Feb 9, 2002
    3,054
    Seattle
    Full Name:
    Gary
    Your symptoms sound EXACTLY like what I experienced when my Dinoplex ignition box failed in my Boxer.

    If you can, borrow a Dinoplex unit from another Boxer or a 400i, plug it in and see how your car runs.

    They are very easy to remove. There are just three nuts that hold it on the mounting studs and one female electrical connector that pulls out of the unit to disconnect it. Takes maybe five minutes to pull it out.

    I ended up switching over to an MSD ignition box, because Dinoplexs are so unreliable and expensive to replace.

    Here's a thread regarding MSDs in Boxers.
    http://70.85.40.84/~ferrari/forum/showthread.php?t=53191
     
  9. jrg1

    jrg1 Karting

    Nov 20, 2003
    60
    nyc
    Full Name:
    john
    Thanks everyone for your replies......I will be sure to let you know what we find. Preventing people from just throwing money at problems is one of the things that makes this site so great. Thanks again.
     
  10. Bryan

    Bryan Formula 3

    You can test if the boxes are the problem by bypassing them completely FOR A SHORT TIME, i.e. long enough to start the car and see if it runs OK. However, if your present symptoms are intermittent, this procedure may not be sufficient to ID the box as the problem. I'd probably do this on one side at a time.

    The general idea is to:

    Disconnect the signal from the coil to the box. Normally, this signal is amplified in the box before going to the points.

    Re-route the coil output directly to the points in the distributor.

    To do this, you'll need a wiring diagram for your application.

    The following describes the process for a Dinoplex AEC 104 BW. I have done this on my 365 GTC/4 that was re-fitted with AEC 104s from stock AEC 103 A.

    Disconnect the elctrical connection from the box. Using a short 14-18 guage wire, connect the pin (#3 in the AEC 104) that carries the coil negative signal to the pin (#4 in the AEC 104) that goes to the distributor points, R1 if you have two sets of points in a distributor.

    http://home.earthlink.net/~fchat/images/Generic%20Bypass.jpg
    http://home.earthlink.net/~fchat/images/104%20BW%20Bypass.jpg

    All that said and while the above worked and identified the boxes as being OK, I still plan to refit with two MSD 6As.
     
  11. henryk

    henryk Formula Junior

    Dec 9, 2003
    479
    Door County, WI
    jrg: I would also check the distributor, for frozen weights, cracked carbon pile, and frozen advance. These are things that I had to fix on my BBi, last summer........it did cause erratic running.

    Just another item to consider.
     
  12. jrg1

    jrg1 Karting

    Nov 20, 2003
    60
    nyc
    Full Name:
    john
    Thx - just did the dist. last month and found frozen weights and a seized outer bearing, and a leaky inner bearing........but thanks.
     
  13. parkerfe

    parkerfe F1 World Champ

    Sep 4, 2001
    12,887
    Cumming, Georgia
    Full Name:
    Franklin E. Parker
    I too had my alternators rebuilt to solve a running hotter than normal issue. The alternators were not putting out enough power to turn the cooling fans full speed. That was discovered only after I had the radiators recored, thermostat replaced and several other parts replaced to no avail. It seems a bad alternator can cause varied symptoms!
     

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