Electronics Need help wiring something up? Thinking of adding an electrical component to your car? Need help troubleshooting that wiring glitch?

WEAK SPARK AT COIL

Old 03-18-2012, 01:07 PM
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Car: '91 camaro z28,imsa widebody
Engine: 383 ci l98,lt1 induction
Transmission: race built 700r4 , ratchet shifter
Axle/Gears: 342;1 detroit true trac diff
WEAK SPARK AT COIL

ive just built a 383 for my camaro,put it in the car but it wont start, ..ive got a weak(yellow) spark from coil but its not man enough to jump from rotor to cap,if i hold coil lead to earth it'll spark about 3 mm from body
, ive tried it with another dizzy/amp and coil from a friends iroc, i have 8 volts cranking over at the pink wire to coil, if i hard wire the coil to the battery it may??? try to fire now and then(rarely)
obviously my dizzy/amp and coil are new but stock items, ive checked all continuity on feeds and earths, the only feed i havent tried is ecu voltage but surely it wouldnt have a spark at all(would it?)
do i get a msd coil?? cant understand how i get weak spark?????????
heeelp
Old 03-19-2012, 12:23 PM
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Re: WEAK SPARK AT COIL

Sounds like a bad coil to me. I'd return it to swap for a new one.
Old 03-19-2012, 03:49 PM
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Engine: 383 ci l98,lt1 induction
Transmission: race built 700r4 , ratchet shifter
Axle/Gears: 342;1 detroit true trac diff
Re: WEAK SPARK AT COIL

ive tried another coil and dizzy/amp., same ,
just tried mates iroc-z tonite and that has near as 12v ignition and cranking voltage, mine has 12v ign but only bout 8v cranking???
Old 03-19-2012, 08:45 PM
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Re: WEAK SPARK AT COIL

According to the wiring diagram, there are two pink wires. One comes from the ignition switch, one comes from the distributor. Which pink wire are you testing.

If you're only getting 8V from the pink wire that comes from the ignition switch, you may need to remove the ignition switch and clean the contacts or replace it. It should pass a clean 12V as long as the battery is giving it 12V. I would check what voltage you're getting at the switch, the problem could lie before the ignition switch as well (Bad ground/shorted hot wire)

If you're only getting 8V from the distributor's pink wire, I'm not sure what to check next, as I don't have a diagram of the internal circuitry.

Here are the two wiring diagrams (Depending on the engine your car originally had)
http://austinthirdgen.org/mkportal/m...ine_wiring.gif

http://austinthirdgen.org/mkportal/m...ine_wiring.gif
Old 01-14-2016, 04:52 PM
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Re: WEAK SPARK AT COIL

Bump
I'm having the same problem with a 350 iroc weak spark at the coil even though I hve used a good coil I needed to know if u ever found ur problem and what it was
Old 01-14-2016, 09:44 PM
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Re: WEAK SPARK AT COIL

Im guessing you are running an HEI dizzy with a carb set-up right? If so you cant use the original pink wire that used to go to the original dizzy. You have to run your own from a 12v switched (hot in run) source.
Old 01-14-2016, 09:50 PM
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Re: WEAK SPARK AT COIL

Holy smoke, i just realized how OLD this thread was...lol I was answering the original poster! Sorry Gary2424, my answer may not apply to you. That guy was building a 383 and probably didnt have a stock CC controlled set-up
Old 01-15-2016, 12:06 AM
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Re: WEAK SPARK AT COIL

Originally Posted by DonW
Holy smoke, i just realized how OLD this thread was...lol I was answering the original poster! Sorry Gary2424, my answer may not apply to you. That guy was building a 383 and probably didnt have a stock CC controlled set-up
No problem mate I was just searching my issue I'm havering the same problem on (as far as I know) the parts that came on the car in 1990 minus the ignition module which I replaced a few months ago it appears I'm getting a low spark at the coil and it's not tuff enough to carry through to the distrubutor much less down the plug wires and plugs to the cylinders
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