1967 f100 ignition relay problems?

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Carb
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1967 f100 ignition relay problems?

Post by Carb »

Hey all,

The other day went to turn off engine and switching it to off did not turn it off. Removed the ignition relay wire to turn it off. seemed to work as restarting and turning it off again worked fine. I should add the relay appears fairly new, and I have cleaned the positive contacts area recently and replaced the positive cable to the relay as well.

This morning no juice whatsoever. no clicking, nothing. tested the voltage and the battery was around 3-4volts. removed the relay ignition and starter lines and tested again and i was back to 12 volts. With the engine switched off shouldn"t there be no voltage from the positive to the ignition wire? I am trying to figure if either the iginition or the relay solenoid is bad. Switching to auxilary I can't even turn on interior cab lights.

I think I have a voltage leak but not sure (and not electrically smart enough) to get my head around it. I feel as though when I switched off the engine the relay maybe didnt shut off and there was a slow leak overnight draining the battery.

Thoughts? thanks in advance.

ps. relatively new battery, voltage regulator and new alternator.
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sargentrs
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Re: 1967 f100 ignition relay problems?

Post by sargentrs »

I would suspect the solenoid. They are known to be bad right out of the box. I've had to replace mine 3 times before getting a new one that worked.
Randy
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
Busboy
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Re: 1967 f100 ignition relay problems?

Post by Busboy »

I think I have a voltage leak but not sure (and not electrically smart enough)

The first thing I would do is look up the wiring diagram for your truck on this site and make damn sure all the wires and cables are in the correct spot.
Secondly, there is no such thing as an ignition relay on these trucks. The starter relay, or solenoid as some people call them, has an ignition resistor bypass function but has nothing to do with keeping the engine running when functioning normally. Thirdly, make sure all the engine ground wires and cables are intact. :thup:
1967 F-100 4x4 custom cab.
Another 67 F-100 4x4 custom cab.
2016 F-150 Eco-Boost 2.7 liter. (It will smoke the tires!)
1972 F-350 Sport Custom cab & chassis.
1972 F-250 Explorer Special, Camper Special.
1971 F-100 custom. 302, C-4, p.s. p.b. factory 65 amp alternator with transistorized voltage regulator.
Carb
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SOLVED: Re: 1967 f100 ignition relay problems?

Post by Carb »

Thank you all for your help,

I figured it out. sure enough the solenoid was bad, replaced it then the engine would turn over but no spark, 12 volts going to coil, but with the pertronix 1 only 7.5 volts. After some testing found the pertronix had fried, I think because the solenoid allowed 12 volts to get to the pertronix for an extended period of time.

I replaced with points as a stopgap and it fired right up. Now in the process of replacing with a pertronix 2 and some suppression style spark plug wires. Get that on monday. afterwards plan on checking timing again.

Thanks for all the help, I did not expect two different things to go down at once, threw me off.

Carb
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sargentrs
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Re: 1967 f100 ignition relay problems?

Post by sargentrs »

I'm not a big fan of Pertronix. I went through 2 sets in under a year on my Fairlane. The first one lasted 9 months. The 2nd one lasted 3 weeks. Swapped to Duraspark and have no problems since. Spent less on the Duraspark conversion than I spent on one of the Pertronix units. Just my :2cents:
Randy
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
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