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| losing spark https://www.ausmini.com/forums/viewtopic.php?f=2&t=74963 |
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| Author: | minilee [ Thu Jan 12, 2012 7:21 am ] |
| Post subject: | losing spark |
hey guys been having problem with my car backfiring and running rough , I just a got a member to help me tune it but still the same , I have checked the carb needle and its oiled up , dizzy is brand new , timing is correct I think , got it done by a mechanics .. It was running nicely for a day and its started backfiring again , but something I notice is that when I pull the the plugs out to check the spark I got a jolt (shock ) from touching the body , does that mean its got to do with my earth ? faulty dizzy ? loose cables ? which is causing my car to run rough, I don't know if this all make sense , this is my first mini. HELP |
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| Author: | drmini in aust [ Thu Jan 12, 2012 7:38 am ] |
| Post subject: | |
1. If it has points check the points gap is .015". Weird things happen when they close up.. like you are experiencing. 2. Whilst the dizzy cap is off, spray it all over inside and out with WD40. Then wipe dry with tissues, inspect for any cracks, spray lightly inside again, shake and refit. Dirty or damp caps can cause misfiring or crossfiring. |
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| Author: | minilee [ Thu Jan 12, 2012 7:55 am ] |
| Post subject: | |
i was just checking my leeds , found that one was working properly , didnt even spark when i heard it near the plugs , would that have cause the backfire ? i keep getting shock , the whole dizzy is brand new around 3 weeks old I think i need to change my leeds ? |
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| Author: | drmini in aust [ Thu Jan 12, 2012 9:42 am ] |
| Post subject: | |
Put a multimeter on each lead. Good ones measure 1.5-2K ohm when new. Any I find at 5K or more, I bin em. Most cheapies including Top Gun are just a bit of carbonized string inside. These go bad in as little as 4 or 5 years. I buy only Bosch inductive core leads from Supercrap, after 4 years they still measure as new. Cost was $5.95 a lead last time I looked. Don't forget the coil lead too. 
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| Author: | simon k [ Thu Jan 12, 2012 11:36 am ] |
| Post subject: | Re: losing spark |
minilee wrote: timing is correct I think , got it done by a mechanics ..
It was running nicely for a day and its started backfiring again I think you should take it back to the mechanic - it sounds a bit like the distributor is loose. Grab the distributor and see if you can turn it you should get a shock from all 4 spark plug leads 
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| Author: | minilee [ Thu Jan 12, 2012 4:40 pm ] |
| Post subject: | |
That's what happen before , he didn't tighten the dizzy and it came loose while driving , I tryed turning it , its fixed pretty tight , I got a new set of leeds and it seem abit better , still backfire but not as bad as before , I'm starting to think that the dizzy isn't time properly , this happen to me before I started playing with the dizzy n replacing it . |
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| Author: | goodie [ Thu Jan 12, 2012 9:13 pm ] |
| Post subject: | |
The clamp that tightens on the dizzy hasn't closed right up has it ? Can you see any sort of gap in the clamp , where the bolt goes through ? |
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| Author: | drmini in aust [ Thu Jan 12, 2012 9:44 pm ] |
| Post subject: | |
goodie wrote: The clamp that tightens on the dizzy hasn't closed right up has it ?
Can you see any sort of gap in the clamp , where the bolt goes through ? Early dizzies 25D etc can crack their flange where the clamp is, as Lucas made it hollow inside. They got smarter on 45D dizzies... and made them solid. 
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| Author: | minilee [ Thu Jan 12, 2012 10:25 pm ] |
| Post subject: | |
Hi kevin , i have tryed sending you a private msg but it seems like its not going through just in regards to some extractors an su ! |
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| Author: | kirby [ Thu Jan 12, 2012 11:26 pm ] |
| Post subject: | |
drmini in aust wrote: Put a multimeter on each lead. Good ones measure 1.5-2K ohm when new.
Any I find at 5K or more, I bin em. Most cheapies including Top Gun are just a bit of carbonized string inside. These go bad in as little as 4 or 5 years. I buy only Bosch inductive core leads from Supercrap, after 4 years they still measure as new. Cost was $5.95 a lead last time I looked. Don't forget the coil lead too. Whoah, I usually find your opinion invaluable doc but you seem to be a bit confused here. Even top guns basic bottom end lead are spiral core wire while the bosch leads we get in Australia ex supercheap are just very basic single core wires (aka "carbonized wire") with no active shielding, (the "inductive core" should say enough about that) they wreak havoc on electrical ignition like your pulsar dizzys so Id bin them asap. Also a resistance check with a cheap dc automotive multimeter is useless as it will only give you basic continuity check and no indication of how its dealing with the AC spikes provided by the coil. Further a sufficiently shielded spark plug lead like the spiral core top gun leads will measure 4k ohm from new simply because their suppression is better so advising to bin leads over 2k ohm resistance is very misleading (this only complicates things as the mini uses non resistor plugs) Leads come in 2 parts the conductor that wants to move as much voltage as possible and the resistive shielding that protects other components from emi, crucial on electrical ignition vehicles not so important on points vehicles. Of course this has to be viewed as a whole to mean anything; including plugs, coil and the venerable condenser Also saying leads go bad in 4 or 5 years is useless. how many ks do you do in a year? not to mention the coil lead is working 4 times as hard and should be replaced more frequently than the plug leads. What Im trying to say I suppose is swap out the leads with a known good set is the cheapest easiest way to rule out an ignition problem without some serious hardware. As usual Im happy to be proved wrong and I personally use eagle brand leads and wouldn't touch bosh leads if they where free. |
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| Author: | mini13 [ Thu Jan 12, 2012 11:28 pm ] |
| Post subject: | |
another good one is the earth wire from the baseplate to the dizzy body going intermittant. also I have known a few 1275 gt tacho's to go short circuit intermitantly which kills the spark, took me ages to sus that the first time! |
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| Author: | Convertible Mini [ Fri Jan 13, 2012 6:29 am ] |
| Post subject: | Could have a fouled Plug |
If you have just fitted new plugs make sure you did not get a crook one. Or if you have fitted new points and condenser make sure the condenser is not faulty. If you got a shock when you touched the leads it sounds like there is a high resistance somewhere. Plug or lead. Spark will travel to earth the shortest way in this case :your hand" as it's usual path is blocked so to say. |
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| Author: | drmini in aust [ Fri Jan 13, 2012 12:36 pm ] |
| Post subject: | |
Kirby I will go destroy a new Bosch lead today in the interests of science. :P The Bosch ones in my car now are 4 or 5 years old and still measure 1-5-1.9 K ohm depending on length. I can hose the motor with the engine running and it won't miss a beat. OTOH I've had 3 sets of Top Gun leads over the years, all had string in em, all failed to work reliably in wet weather after 3 or 4 years. They may be better made now, but I've not bought any due to previous poor reliability. OK I have just cut up a new Bosch lead. The core appears to be fibreglass strands (not string) and it has a very thin wire conductor wound around it. No carbon powder at all is in there. I would say their term `inductive core' is pretty much correct...
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