Hello.
79f150, straight 6. 4x4 4spd. 130AMP alt.

Since this freezing cold.
I go out to start her in the morning. After a while the temp will read H/ (like about to over heat). It's like 5deg out. Heater is working. Once I hold in the clutch, the headlights get brighter, the heater blower blows harder and the temps drop fast down to where they should be. While I'm driving, same thing. Not sure if it is actually overheating, but to be sure, I hold in the clutch every few min to drop the temp down... of course when I hold in the clutch, a lot more electricity flowing it seems with the lights and heater blower.

I get to work and check the coolant. Its very warm/hot and the main tubes are soft as they should be.

What does any of this have to do with the clutch?

 

Sound like a faulty ground strap from engine to cab. edit: Pressing on the clutch loads up the metal points allowing more electricity to flow where it really shouldn't be.

Had a similar thing go on with my clutch where the stereo would cut out if I let the clutch out with a bang. That's when I noticed other oddities with the electrics. Wiggled my ground strap and found my problem. Wiggling wires is sound diagnostic advice!

Could use a multimeter and see if there is any volts between engine, cab, or frame. Should be all be 0 volts. Ohm'n those should be 0 Ohms (or close to it, like if your touched the leads together).

 

Thanks man. Found someone on the internets with the same issue.
redlinegti.com ? View topic - weird electronic issue with clutch.

Kinda sounds like what's going on.

I cleaned my main terminals, but that's all I could stand out there @ 5deg.
lol.

 

I had a similar issue on my '79.....turn on the heater blower and the temp and oil gauges would climb. Ran a dedicated ground wire to the cab and everything works right again.

 

Right from the battery terminal to cab?
Is the ground strap from motor to cab, near the back of the block area?

 

Heya neighbor,

On mine, the ground strap is on the driver's side near where the steering column comes through the firewall. It's pretty out in the open. Remove it and clean up the bolts with a wire wheel/brush and then reinstall nice and tight.

Hopefully it helps.

Just be careful to keep dry so your hands don't freeze to the block. This weather is COLD.

 

Yo man! Lol ikr. Next week we are going to hit -12.
Ok I did see that one. Do we know the gauge and length of that one? Since I'm down there, new would be fine too. Or i can just remove and walk a block to Orylliez.

 

Dang, you're not kidding. Just looked at the weather forecast for next week and am seeing what you mean.

I don't know what the gauge is, but mine's a braided cable, since it needs to be flexible.

Jegs Ground Strap

This universal one says it's 15 inches.

 

Yeah, I just ran a 12 ga wire from the batt ground to the firewall. It was a temporary fix to get me going. Still there...haven't got around to fixing the ground straps.........soon.

 

I have several grounds in mine.

One from the battery to the fender right next to it.
One from the battery to the frame.
One from the frame to the starter.
Then the braided ground strap from the block to the firewall.

It really makes a difference, especially when they're all fresh, new wires.

 

X2 and should have 1 from fire wall to hood on passenger side.
Dave ----

 

You dudes were right. Sounded weird, but it's all true.
Found the grounding cable. It was back there hooked up to the same bolt the coil uses to attach to the engine block. The cable, was just hanging barley on the firewall, while being all corroded and falling apart. Removed it, also had to remove the coil since it was the same bolt, the coil also looked very corroded and caked on oil. Removed those, use some cleaner and wire brush to clean up the bracket and bolt places. Also took a wire wheel to the firewall spot. Cleaned up and replaced both the grounding strap and the coil since I was there. Bam. Problems solved and she starts smoother and seems to have better throttle.

Thanks!
I do metal casting, so the old copper cable will be melted down and turned into something.

 

I'm not familiar with a '79. Is there electrical on the hood that requires a ground?

 

Awesome! Glad you got that fixed. Good, solid grounds are way too commonly overlooked and cause a lot of issues.

And yes, if it's bad enough, you'll definitely have better throttle response, performance, gas mileage, the whole shebang, simply by fixing a bad ground since that can cause a weak spark from your ignition.

 

Heck ya man. I found out my truck will fit in the tiny garage. barely. had the wood stove going in there. was good! I need to do my other tune up bits, ready to go.

John, I think I was reading the reason why they had the hood grounded was due to the trucks that came with a radio. So the antenna has better ground. From what I understand. Mine works fine.. but only time i use AM/FM is when we go to the movie drive-ins.