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| pulsar dizzy and missing? https://www.ausmini.com/forums/viewtopic.php?f=2&t=55685 |
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| Author: | MG Rocket [ Sun Aug 02, 2009 5:51 pm ] |
| Post subject: | pulsar dizzy and missing? |
I have fitted a pulsar dizzy as per the Doc and as others have prescribed, but I have this persistent miss although having fitted new leads, cap and rotor. The thing I noticed....at idle the spark looks pretty good and as I rev it the spark weakens right off, even at moderate revs. Rev a little harder the spark become faint and intermittent. Failing coil? Something else that concerns me.....when I re-assembled the dizzy I noticed that the space between the star shaped rotor and the two pronged metal thingy is adjustable, so I just set it at whatever and worry about it later. Would this gap effect spark at higher revs? |
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| Author: | MG Rocket [ Mon Aug 03, 2009 5:52 pm ] |
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Anybody got an opinion? |
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| Author: | MG Rocket [ Tue Aug 04, 2009 6:33 pm ] |
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Ok, I have just had another look at my problem. When I observe a plug shorted to the engine block, I notice that after every ten sparks or so it misses a spark. As I rev the engine, the spark can temporarily go out. It's all very random but it happens on all 4 leads. So what do you think.....Coil? Or is there something wrong with the dizzy? |
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| Author: | simon k [ Tue Aug 04, 2009 8:22 pm ] |
| Post subject: | Re: pulsar dizzy and missing? |
MG Rocket wrote: that the space between the star shaped rotor and the two pronged metal thingy is adjustable,
so I just set it at whatever and worry about it later. set it so that each prong is the same distance from the points of the star otherwise it does sound like the coil, don't know if it makes a difference, but did you use the pulsar coil? don't go rushing out to buy a new one just yet though, I priced one at $180!! 
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| Author: | Mick [ Tue Aug 04, 2009 8:32 pm ] |
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It might also be the ignitor module within the dizzy, they fail from time to time as well. Swap the coil out with a known good unit coil as Simon mentioned and then look at the module. I'm not sure what you mean about the pronged thingies however...a pic might help.Pick up gaps are important however if this is what it is... |
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| Author: | MG Rocket [ Tue Aug 04, 2009 8:36 pm ] |
| Post subject: | Re: pulsar dizzy and missing? |
simon k wrote: set it so that each prong is the same distance from the points of the star Yes I did center it, but I sort of remember that the space could be varied simon k wrote: otherwise it does sound like the coil, don't know if it makes a difference, but did you use the pulsar coil? don't go rushing out to buy a new one just yet though, I priced one at $180!!
I paid an extra $15 dollars to get the original coil, I also just tested it's ohms but got a 000 reading but that sounds like my meter is faulty. So tomorrow I'll check another coil to see if the meter is ok. $180!!!!... of course the windings are a fine pure gold obviously not copper. |
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| Author: | MG Rocket [ Tue Aug 04, 2009 8:42 pm ] |
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Mick wrote: Pick up gaps are important however if this is what it is...
I'd say that is what I meant. The star shape rotor, rotates between two blades opposite each other. As I remember it, you could move it back and forth to adjust the gap. |
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| Author: | Mick [ Tue Aug 04, 2009 8:47 pm ] |
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Rule of thumb with pickups (in my line) is to adjust close without touching. Make sure you take into account any shaft movement present to adjust the gap accordingly, you don't want them to touch under any circumstance. If the gap gets too large for a pickup then it will become too weak to be picked up reliably. |
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| Author: | MG Rocket [ Wed Aug 05, 2009 7:58 pm ] |
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Ok, I've tested my coil and it registers 1.9 ohms and it should be 1.5...Right? So is this significant? Another thing that worries me a bit....When I was fitting the dizzy some time back, I had wired it directly to the battery but forgot about it and a day later I noticed it was still hot wired..... Would this damage the module? |
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| Author: | Mick [ Wed Aug 05, 2009 8:09 pm ] |
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MG Rocket wrote: Would this damage the module?
Yes it can damage the module if enough heat builds up, but not always depending on how efficiently the heat dissapates away from the module. A resistance check of the coil won't always identify a faulty coil, if the insualtion is breaking down at high voltages, then a low voltage ohm meter won't have the grunt to identify a short i nteh windings. Get a known working ignition coil and put it in. It doesn't really matter what it is out of as the dizzy will not have a problem firing it as it uses a high power coil in the first place, it will have no problem switching a lower power coil such as a standadr mini unit. If the problem persists, then it is not the coil. If the problem persists when you are holding the lead adjacent to the block, then it is not the spark plugs. If you are certain you replaced the leads and cap and rotor with new items, then it probably won't be that either... It leaves the ignition module and the quality of the supply connections. Check these as well as a loose connection will do just this. |
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| Author: | MG Rocket [ Wed Aug 05, 2009 8:37 pm ] |
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Thanks Mick. I have two coils I could use.... a brand new EL Ford one or the original points coil. Do you reckon I should rig up the Ford one? Another curious thing was in the early mornings the misfire would be noticeable at 40 mph but in the afternoons coming home it would be at 50 mph. The only difference I could tell was the ambient air temperature. |
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| Author: | Mick [ Wed Aug 05, 2009 8:47 pm ] |
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yeah that sounds a little curly....if its an intermittent short or open circuit in the internal windings of the coil then anything goes I suppose... Hairline fractures in copper conductors can act stragely sometimes as well... Measure the falcon's resistance, it should be about the same or greater than the pulsar's rated coil. If it is put it in, if its not then try to find another one. A standard mini coil will suffice long enough to see if the fault is removed or remains, although the gaps on your plugs will need to be checked to be 25 thou to work correctly with the low output standard mini coil. |
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| Author: | MG Rocket [ Thu Aug 06, 2009 7:30 pm ] |
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Mick I did as you suggested....used the points dizzy and reset the plug gaps (actually reset new NGKs) ......well everything got worse....could not get the revs past idle. So it's looks like I cooked the module. Mick, thanks for your help. Oh, one other thing, the plug thread in #1 cylinder feels a bit "soft"...is there something I can do to make it last a bit longer and keep the plug tight? |
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