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Old 08-31-2013, 11:18 PM   #1
71 super
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Ignition question

Help i am having ignition troubles that just showed up. truck runs ok for a of time- three miles or so sputters and then dies. will spin over a couple of times with no fire and then acts as if there is no power. I replaced coil on hunch and changed fuel filter, cranked and ran ok. Couple of miles later I am back to where I started earlier. Have I fried the pertronix module or is it a resistance issue? Mind you I have drive truck quite a bit as it was set up and now this problem raises its head.. .. I have a pertronix replacement pick- up and now their 1.5 ohm coil(original delco tested at 3 ohms). The resister yellow wire shows 11.56 volts with switch on, with positive meter line at coil and jumper to ground still shows less than 12 volts. The battery shows 12.5 volts across terminals. According to pertronix , the unit must have 1.5 coil no resistance wire and 12 volts minimum to positive side of coil. What is the best method to get the 12 volts there? I felt like I could go from unfused terminal at fuse block to get the 12 volts I need( done this before to hei types). Any suggestions are appreciated.
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Old 09-01-2013, 02:58 AM   #2
luvbowties
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Thumbs up Re: Ignition question

Just for experimenting, use that terminal from fuse box to operate a relay; run a fused wire directly from +BATT to relay--and then, when actuated by fuse-box terminal--from other output terminal to coil. Will give full batt voltage to coil, definitely above 12 volts(13.5-range) IF your BATT is good.
Sam
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Old 09-01-2013, 03:24 AM   #3
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Re: Ignition question

since you mentioned fuel filter. where is it located in line, before or after the pump?
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Old 09-01-2013, 06:16 AM   #4
cdowns
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Re: Ignition question

i have always just removed the resistaance wire from the harness and installed a new wire to the bulkhead connection then rewraped the harness and got a nice factory lookin harness with the updated wiring
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Old 09-01-2013, 06:48 AM   #5
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Re: Ignition question

Sounds like resistance issue. Resistance=heat and low voltage. Bad/old connections or splices somewhere lowering voltage as it heats up probably.

Check out madelectric. I put his 'New System' in, and it came with a lot of good info and turned out to be a really good upgrade for the money. Ran better and stronger afterwards too.
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Old 09-01-2013, 09:50 AM   #6
71 super
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Re: Ignition question

The fuel filter was at carb, and it was offering resistance. The harness is a new harness from m&h, truck was restored 13 years ago but had sat a lot. The pertronix has been in place for at the entire time, however,this issue just showed up. Have had intermittent fuel issues but beginning to think that it has been an ignition problem due to resistance. I am going to make up a jumper and try that to see how it goes.
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Old 09-01-2013, 10:01 AM   #7
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Re: Ignition question

Don't overlook the fuel pickup tube in the tank Harold. I had a 70 Gmc about ten years ago that started acting like that and it ended up being an almost completely plugged up pickup tube, I'm sure that truck was not the only one that had that going on but you rarely see anyone else find the same thing. I also have done and recommend what cdowns did for a power source, replace the resistor wire at the bulkhead. It's the wire that drops the voltage, it's 12volts at the terminal.
Good luck

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Old 09-01-2013, 10:25 AM   #8
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Re: Ignition question

Sounds more like a fuel issue and also consider looking for a stuck needle. Sounds to me like a flooding issue. Next time take a look at float bowl levels when it dies on you. Lower than at rest then maybe filter, etc.. Higher, needle/seat.
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