ground strap on A body to motor??

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tom340

tom340

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This is an old issue not resolved.. (gauge works, sender unit Ok, good ground from sender to chassis) Real quick the problem is the fuel gauge works just fine until the motor is started. Then I LOSE power TO the back of the fuel gauge. Its a '70 rallye dash, fuel, oil press and temp off same power.
<Another Duster owner just told me he had similar problem and asked me "is your engine grounded?" I've never really noticed a Duster, Dart or Demon engine ground harness. His gauges were all wacked after the motor re-installed from an engine rebuild. He was at a loss for what had happened and his mechanic either attached or "re-attached" a ground strap from the heater box bolt to an exhaust stud bolt and he said the gauges worked fine again.
< I want to stay clear of wondering if the sender unit is bad (not) or the sender is not grounded (it is-and tested) or if the gauge is bad (also tested-not the problem) My question is does anyone else have a ground strap from the chassis to the motor????????????? Does anyone know for sure if they came grounded from the factory, and if so where did this ground connect from/to? Im hoping its just this simple! Thanks for any feedback
One last thing, I have a black ground wire that for some reason is attached from the wiper motor to a heater core bolt. Not sure of the purpose, or if its even right..
 
My Duster had a ground wire from the motor to the fire wall (S6) as well as the wire between the heater and wiper motors. I ran a strap between the block and firewall (bell housing bolt to heater motor stud) when I dropped the 440 in. I also retained the wire between the two motors. I would definitely run one if it's missing.

It might also be worth looking at your ignition switch. I have an old Dodge truck where the ignition switch doesn't always make the connection when it moves from the start to the run position. Sometimes the gauges are dead till I manually rotate the switch farther towards the run position.
 
I have a 1970 Duster with ralley gauges. It is still apart.I am going off my memory .The ground circuit should be your negative cable to engine block with pigtail to engine compartment; heater has a ground circuit right side rear of engine.On a A/C car the heater box is grounded right front inner corner.There is a ground clip at fuel sender and fuel line.One of the bolts holding up the steering column should have a ground strap.On a freshly painted car they say where ever you put a ground circuit, break the paint surface to get a good ground.When I get the Duster back from the paint shop,I am going to improve the original ground circuit of the car.
 
Here's my basic old car drill. Heavy gauge ground straps, from battery to frame, from frame to engine, from frame to body "for Chebies", heater blower motors to body. Most engines have a small ground strap near the back from either intake or cylinder head to firewall. And corrosion can build up between the bolt and body or cable. Or sometimes people just bolt a ground strap straight to paint. All of these reasons are easily overlooked and become a gremlin. Happens alot with taillights and marker lights that have build up of corrosion, one side is brighter than the other etc..
 
70Duster440 said:
My Duster had a ground wire from the motor to the fire wall (S6) as well as the wire between the heater and wiper motors. I ran a strap between the block and firewall (bell housing bolt to heater motor stud) when I dropped the 440 in. I also retained the wire between the two motors. I would definitely run one if it's missing.

It might also be worth looking at your ignition switch. I have an old Dodge truck where the ignition switch doesn't always make the connection when it moves from the start to the run position. Sometimes the gauges are dead till I manually rotate the switch farther towards the run position.
Click to expand...

That wire from the wiper to the blower we scabbed off a parts car (was missing from mine) the other 70 duster was an unmolested /6 car we were certain it serves a purpose. On my electrical schematics it shows both motors grounded, but not specifically to each other.
The ignition switch is the last item to change.....The gauge works when the switch is turned forward just B4 you engage the starter. But to me it seems the switch is in the same position when the engine is running as is in the on position. I have an annoying screach and rattle in the steering column that needs work anyhow so its a good time to replace that switch anyhow.
 
That noise in the column would be rusted bearings. The ground starp from engine to firewall is factory and nessesary. Factory added another from ground at battery to radiater support around 1972, 73
 
Phantom70Duster said:
I have a 1970 Duster with ralley gauges. It is still apart.I am going off my memory .The ground circuit should be your negative cable to engine block with pigtail to engine compartment; heater has a ground circuit right side rear of engine.On a A/C car the heater box is grounded right front inner corner.There is a ground clip at fuel sender and fuel line.One of the bolts holding up the steering column should have a ground strap.On a freshly painted car they say where ever you put a ground circuit, break the paint surface to get a good ground.When I get the Duster back from the paint shop,I am going to improve the original ground circuit of the car.
Click to expand...
K this is good. Im running down to the garage and back up checking out how we have things connected. We have the negative cable grounded to block, but not pigtailed to chassis.Thats a potential issue. I cannot remember ever seeing any nice restorations at shows with the neg. cable pigtailed to the chassis though. The fuel sender is correctly grounded. Were Ok there. No ground strap from the heater blower to the back of the cyl head! I found the bolt hole so that needs to be fixed asap. The ground strap on the steering column is connected, Ok there. Looks like I have two issues to address here.
 
RedFish said:
That noise in the column would be rusted bearings. The ground starp from engine to firewall is factory and nessesary. Factory added another from ground at battery to radiater support around 1972, 73
Click to expand...
Are the bearings available or (gulp) re-pops out there? Im sure thats related to the rattle in the column Im getting.
 
Yes the bearing is available.On my 70 duster it is an automatic column shift.There is one bearing at upper part of the column.Then there is a plastic white bushing at the base of the column.Before attempting this repair I would suggest locating a factory service manual.I would pull the column completely out of the car.Obtain all your parts.Allow yourself plenty of time for the repair.After looking at service manual make sure you have all the proper tools to take the column apart.When removing the upper bearing be careful not to damage the shaft.The reason I say that is the shaft is designed to collapse on impact and has plastic shearpins in it.So if you're brutal with the bearing you may break the pins and then you have to locate another shaft.It is not that difficult to do - just time and patience.I completely took my column apart and rebuilt it.I lubed the remaining parts and put it back together.The column is not in the car yet if you want to see what it looks like I would be more than happy to post what the finished product looks like.
 
Tom, talk to Rick@Laysons. I know he makes the ground wires and battery cables. He can tell you what is correct for your car.
 
I now believe in majic jeannies. Found the cure by chance, hooking up some mechanical gauges and a tach. I had a friend Ed who was up for the summer from Florida hook up the electrical power supply and grounds. While he was under the dash he pointed out some bad connectors, plugs and all that electrical stuff I hate and he volunteered to fix 38 years of things that happen while other people own the car before you do. He didnt even like the factory ground so he improved that as well. So job complete, we check for lights and function..double check everything else electrical for function also. All is OK. I notice on the drive home the fuel gauge is now reading I have gas........."Course I'm thinking "Now whats wrong the the fuel gauge". After all we had it pegged as the ignition switch as the problem right? So we stop at Sunoco and filler up. Now the gauge reads FULL. This cant be good right? Sure enuff, the gauge has worked fine since Ed did his thing. Even the E -brake light functions when applied. I can tell you this, {of all the gauges in the car } after not having a fuel gauge that worked for 2 years I cant stop staring at the damn thing
 
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