Author Topic: Intermittent Electrical Problems  (Read 1906 times)

Offline adgalloway

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Intermittent Electrical Problems
« on: February 22, 2019, 12:18:54 PM »
I have a 1984 K10 Custom Deluxe. It belonged to my grandpa and had been sitting for about 8 years until I dug it out last month. I seem to be having a problem with the starter or something else in the ignition circuit.

When I turn the key to RUN the dash lights come on, I can turn on the headlights, the horn works, etc. As soon as I turn the key to START everything goes black. Sometimes the starter barely turns the engine over before this happens and sometimes there is nothing from the starter. Even the headlights won't turn on with the headlight switch once this has happened. If I disconnect the battery ground and reconnect it, that seems to reset things and everything lights up again.  If I pull the battery out and top it off with the trickle charger the truck will start once or twice before the issue happens again.

-- So far I've tested the battery, both with a meter and by swapping it into a 79 camaro with a SB 350 engine to verify it would start that car. The battery is brand new and holding a good charge
-- I've jumped the starter solenoid with a screwdriver to take the ignition switch out of the equation. This didn't turn the engine at all. A small static like spark was visible when I made contact and again when I broke it.
-- I've inspected the battery cables, they are quite old, maybe original, and I cut the rusty connectors off and installed new ones. The ground cable does have some melted insulation near where it connects to the alternator bracket from the battery having shorted out against the frame about 3 weeks ago (I picked up a new set of cables to install today, but haven't gotten to do so yet)
--The ground cable only connects to the alternator bracket on the truck, on my camaro there is a second, smaller pigtail connection to the body, is this extra connection supposed to exist on my truck?
--Resistance of the ground cable (removed) reads 0.03 on my ohm meter.

Any help or advice for trouble shooting this issue is appreciated.

Thanks,

Offline Rapid Roy

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Re: Intermittent Electrical Problems
« Reply #1 on: February 22, 2019, 01:37:54 PM »
Welcome to the site. I would locate all ground connections in engine bay and clean. Be sure bat cables are good and not damaged in any way. May help with your issues.
1974 Cheyenne 10 LWB STOCK 350 W HEI /TH350/AC/4 BBL Quadrajet
Mopar by Birth
Chevy by Choice

Offline adgalloway

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Re: Intermittent Electrical Problems
« Reply #2 on: February 22, 2019, 01:46:52 PM »
Thank you Roy. I'm going to put the new cables on tonight and make sure all connections are clean. I hope you are right. If that doesn't resolve it, would the starter itself be the next thing to suspect?

Thanks,

Offline adgalloway

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Re: Intermittent Electrical Problems
« Reply #3 on: February 22, 2019, 09:59:56 PM »
New battery cables seem to have done the trick. She turns over good now.  I found a broken grounding strap that looks like it connects the firewall to the back of the block someplace. I'm going to try replacing that as well

Offline bd

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Re: Intermittent Electrical Problems
« Reply #4 on: February 22, 2019, 11:34:28 PM »
That broken strap is crucial to properly ground the cab.  It connects between the firewall sheet metal and a 3/8" bolt in the back of the right cylinder head.  The OEM strap is 5/16" braided copper.  You can substitute 10-gauge wire if you are unable to locate a proper replacement strap.  Be sure to allow for sufficient slack to accommodate engine movement.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline adgalloway

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Re: Intermittent Electrical Problems
« Reply #5 on: February 24, 2019, 05:58:23 PM »
Seems I spoke too soon. New battery cables and the engine to cab grounding strap seems to have solved my starting issues, but now I've lost the warning lights for brake and choke when the switch is turned on.

Offline bd

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Re: Intermittent Electrical Problems
« Reply #6 on: February 24, 2019, 06:21:46 PM »
Check the fuses.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)