As I continue my quest to fix the many problems with my 1973 F-250 4x4, one of which is an inopperative instrument cluster (I've replaced bad wires and the IVR) , I have discovered that my truck has exactly one (wimpy) ground from the engine to the firewall, one from what appears to be the AC to the firewall, and one from the battery to the engine block.
I have not found any straps from the engine to the frame. None from the body to the frame, hood to firewall, bed to cab, etc.
Lots of electrical threads mention ground straps and/or "heavy ground wires" but I'm not sure how many I should have and where they should be. What do you recommend? And if there is a thread on this issue specifically, I apologize for missing it.
The negative battery cable grounds the engine block; you should also have a braided ground strap from the engine to the firewall. This should be good and strong because it's the ground for all lighting and instrumentation in the cab and the front clip. I believe the frame grounds with a braided ground strap to the firewall (the frame is not grounded to the engine through the engine mounts as is commonly thought, because the engine is mounted in thick rubber). My '79 doesn't seem to have a ground strap from the bed to the frame (that I can find at least); if that's the case then I'd imagine it's grounding through the bed bolts. It certainly doesn't hurt to add another ground strap there though.
Last but not least, if your truck came with a radio it will have a ground strap for the hood. This provides a larger ground plane for the antenna. It also serves as a ground strap if your truck came with an under-hood light.
dont know if this helps but on mine , the frame is grounded to the lower drivers side firewall at the cab mount . didnt see it till i removed inner/outer fenders
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79F350 Trailer Special. One ton of dent fun!
Thanks guys, this all helps a lot. I suspected there might be a hidden braid or two somewhere. The truck was repainted about 15 years ago and the engine was rebuilt, both by the PO. It appears that he did not reattach all of the main grounds. I am particularly curious about the missing ground from engine block to firewall and whether that is the cause of my non functioning instrument cluster--although I do have dash and headlights. I have kid duty all weekend but I might be able to sneak away and buy a few braided grounds and attach them this weekend. I'll keep you posted.
And FMC 400, I have not yet done the compression check etc., that you suggested in my previous 8mpg post but will update that one when I do. I wanted to do a post fuel leak calculation of my mpg...
I was replacing my solenoid and noticed a silver grounding strap (1" by 14") attached to the body of my 1979/78 F250, just below where the right windshield wiper rests. The other end is so short it can only reach a place on the firewal where a blower motor is grounded. Thing is the blower is grounded and doesn't look damaged etc. Is this where I should ground it then? I suppose it may could fix my instrumentation blackout that I've had since I bought this truck 10 years ago. Thanks in advance and best regards.
That almost sounds like the ground strap for the hood. This was used to increase the ground plane surface area for the antenna on trucks that came with a radio.
I have grounds from batteries to motor & rad support, motor to frame, firewall to motor & hood, rad support to frame, cab mount to frame & bed to frame. It seems the more grounds I put on it the less battery corrosion I got. I hardly ever clean them now
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'79 F250 13" lift 42" Super Swampers
i raised my body 3inches... did other work, caused problems and might have fixed them.
I just noticed my braided cable on the firewall is swinging in the breeze.
Will this fix my no start issue. (almost starting. sounded more like no fiel or low fuel but who know at this point)
REVISION....
reconnected braided ground. put on the only bolt it would reach. fot the top intake over the valve covers. is this safe? a good idea? or a red neck fix untill i get to the store?
turns out not fuel... but my cables are not sending spark to the plugs.. after reading thread after thread. im going to say TFI
symptoms have been intermitant, slow start, and now no start but tries to turn over.
i have a TFI for my brothers Merkur.. i mean my brother has one in the garage from what i have read I could use the merkurs backup tfi for my bronco.
revision...
before i ran off and tossed a part at it.. TFI tested good.
have power at tfi but no power from coil
so no spark
coil has no power out but can i test for power going to it??
alternator had power to it, doesnt mean its working right. any other charging tests before i move forward. haynes didnt have anything for me
either the coil is bade or the alternator , does anyone feel like telling ,e the best way to test this situation?
I have grounds from batteries to motor & rad support, motor to frame, firewall to motor & hood, rad support to frame, cab mount to frame & bed to frame. It seems the more grounds I put on it the less battery corrosion I got. I hardly ever clean them now
Really can't have too many grounds. It's a good idea to at least have the Negative Battery Cable to engine block, engine block to Frame, firewall to engine and/or frame, bed to frame.
On my project I'm adding grounds as I go. So far I've added a ground from the starter to the frame and fame to radiator support. When I put the cab and bed back on they're going to have ground straps too.
One thing I'm doing as I install the grounds is I put a coating of dielectric grease on the terminal and where it contacts the body. This will help prevent corrosion/rust in the future. I also use star lock washers instead of the regular split locks. I feel the star bites into the metal better giving a better connection.
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from what i have read I could use the merkurs backup tfi for my bronco.
