Need help!! Spark problem
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Cargo Master
Joined: Nov 2009
Posts: 2,364
Likes: 117
From: starship enterprise
Thanks for the input. I have been working on it this afternoon, and The bat. volts read 12.05, a little low but it still cranks OK.
The Coil voltage was 6.75, a little low as well today. But as I stated, this problem has been intermitten, so the readings do not remain consistent all the time.
I checked for spark at the coil, meaning I plugged the coil wire into a spark plug and grounded it and sent the "fire now" signal" from the distributor. The spark it really weak, A small blue flame. How I am determining it is weak it by going and putting the exact same spark plug in my dirt bike and kicking it over, and the spark from the motorcycle is way more intense.
Now, Where do I look for coil voltage resistance where I need 8 instead of 6.75? Which wire is that, My book shows a resistor but I am not exactly sure where it may be.
Thanks.
The Coil voltage was 6.75, a little low as well today. But as I stated, this problem has been intermitten, so the readings do not remain consistent all the time.
I checked for spark at the coil, meaning I plugged the coil wire into a spark plug and grounded it and sent the "fire now" signal" from the distributor. The spark it really weak, A small blue flame. How I am determining it is weak it by going and putting the exact same spark plug in my dirt bike and kicking it over, and the spark from the motorcycle is way more intense.
Now, Where do I look for coil voltage resistance where I need 8 instead of 6.75? Which wire is that, My book shows a resistor but I am not exactly sure where it may be.
Thanks.
Thread Starter
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Cargo Master
Joined: Nov 2009
Posts: 2,364
Likes: 117
From: starship enterprise
OH yeah, I forgot, If I hold the spark plug away from the ground, where it has a ga to jump, It sparks HUGE!! Like it will close a 6" or bigger gap and make a big blue flame but without giving it a gap, it will barely fire, just a minimal little blue flame, not enough to light anything.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
6.75 volts is fine. The resistor you're talking about is actually part of the dash harness, in the cab. It's not your problem. My first thought was that you're getting weak spark because the coil is not building enough current, but the voltage check rules that out. My next thought would be to check your wires, cap and rotor again. Is the rotor tab sticking all the way up and making good contact with the inside of the top of the distributor cap?
Any chance you're getting any crossfiring? If you run the engine with the hood open at night, do you see any sparks dancing across the engine?
Any chance you're getting any crossfiring? If you run the engine with the hood open at night, do you see any sparks dancing across the engine?
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Cargo Master
Joined: Nov 2009
Posts: 2,364
Likes: 117
From: starship enterprise
That could be it and that is why I was trying to get it to fire and get it cleaned out. A cross fire is definetely a possibility but I need to get it running again before I really can determine. It seems like the spark from the coil was sure weak from what my other stuff makes though, and i was thinking that after going through the cap, then rotor, then cap again, then wires there might not be enough to make it there. Thanks I will keep fiddling with it, and see what happens.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
Is there any chance that moisture is somehow getting underneath your cap? Have you taken the cap off while the problem is happening to see what it looks like? Moisture-related ignition issues just screams distributor cap.
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Cargo Master
Joined: Nov 2009
Posts: 2,364
Likes: 117
From: starship enterprise
I had it off today a few times, swapped rotors and that helped slightly, it started then tried to take off then crapped out again, so i swapped the rotor, pulled the plugs 2 at a time, cleaned them and cranked the started over a few times with the gas wide open since I had flooded it by this time, and after cleaning the plugs and re installing she fired up and ran it a few minutes, then cleaned up and runs fine, starts a little weak due to the battery still not totally charged, (it is a giant deep cycle) but it seems fine, it dried up and warmed up and is good. Thankd for the help though.
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