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#1
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Intermittent Ignition - probably a loose wire
Hey,
So I've been ignoring the car and it's finally exacted it's revenge. I was leaving work the other night and the car backfired and then nothing happened when I pressed on the gas. I came to a stop and the car stalled and would not fire even though the engine was turning over. I got out and confirmed that fuel was getting to carbs. Then I checked the distributor and found it fairly corroded. I scraped it off and the engine still would not start. I eventually wore down the battery and had to get towed home (oh the shame). The next morning I took a recharged battery and scraped the distributor some more and it actually started. Thinking I might as well replace some parts I replaced the cap, rotor and wires.. what the heck! The next morning again it won't start. So I replace the points. It starts. But again the next day it's the same thing. This time I replaced the sparkplugs and still... no love. By this point I am really puzzled and refer to the Chilton's. I turn the key over and connect a volt meter to the plus side of the coil and the ground. I see nothing which apparently means there is a break somewhere. About the only part I have not replaced in the ignition chain is the white ballast resistor. After fiddling with it I start to get a reading and the car starts. So I cleanup the part and make sure the contacts are good and tight. Of course this morning I get the same deal but the car magically starts working after I randomly fiddle with some wires. I've ordered a replacement ballast resistor and the coil itself is fairly new. I'm not looking forward to tracing where the break is if it's in the wiring. Anyone experience anything similar?
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MB 72 250 M130.923 114.011 170k The Beauty |
#2
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If you put your meter between ground and the +ve supply to the ballast resistor do you get a steady voltage with the ignition on ? If so then try wiggling the wires and see if there's any sudden voltage drop.
If this doesnt show a problem then try repeating it on the coil side of the ballast resistor. If all still ok then problem could be the coil breaking down or the points or the connection between them. |
#3
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I was surprised to learn that a bad Condenser can kill an engine. $2 Condenser was the last thing I replaced after going through the entire system when the same thing happened to me with 250 w114.
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#4
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Really?? Okay I'll have to check that because after tugging every wire possible I cannot find one that cause the ignition to go in and out. It's been driving me nuts!!!!!!
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MB 72 250 M130.923 114.011 170k The Beauty |
#5
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Hmm.. I don't think it's the condensor.. which was replaced along witht he distributor a few years ago.
I think a more likely candidate is the transistor box which is pretty corroded.. still I wish I could determine if it was a bad connection or the box itself. None of my service books include the wiring for the Ignition Control Unit which is the only part of the ignition system that has not been replaced. Quote:
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MB 72 250 M130.923 114.011 170k The Beauty Last edited by gmask; 05-29-2006 at 10:10 PM. |
#6
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I've tried this and now mount of wiggling produces conistant results.. it just suddenly starts working again. As far as I can tell all the connections are good to the wiring the wiring boot on the ICU. So this leads me to beleive that either the ICU is failing or the loose wire is between the ignition key and the ICU.
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MB 72 250 M130.923 114.011 170k The Beauty |
#7
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Okay I remembered that I had a spare ICU and at least for now things seem to be working.. it was either a faulty ICU or simply crusty connections.. can't really be sure which.
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MB 72 250 M130.923 114.011 170k The Beauty |
#8
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intermitant
FWIW I had such a problem and finally figured it out. The coaxial cable to my ignition control unit had been bent and broke and consequently the spark finally died completely. Used a multimeter to check both paths for continuity.Milt.
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Milterino 76 450 S.E.L. |
#9
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Hmm.. well my ICU doesn't have a coaxial connection.. it has three main wires and then a bunch of others terminate on some posts on the back. Since I switched it out with my spare it hasn't been giving me problems.
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MB 72 250 M130.923 114.011 170k The Beauty |
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