Where's the grounds?
Thread Starter
Le Mans Master
Joined: Nov 2004
Posts: 6,128
Likes: 21
From: North Alabama
Where's the grounds?
Ok...have the ground from the battery to the frame (directly under the battery) Also have the ground from the engine to the frame. Where else should it be grounded? While starting it the other night a friend noticed an arc jumping from the dipstick handle to the power brake booster. And the handle was getting HOT! Assumption is...it's trying to find another ground. Never had a problem with it starting but don't want to start a fire under the hood either!
Input or suggestions? 
Input or suggestions?
Thread Starter
Le Mans Master
Joined: Nov 2004
Posts: 6,128
Likes: 21
From: North Alabama
Originally Posted by shafrs3
Maybe your existing ground connections have corroded or loosened? That’s all the ground connections I have on my ’72.
Race Director
Joined: Nov 1999
Posts: 10,643
Likes: 8
From: Foxfield CO 1970 Convertible
There is also a black ground wire from the main harness to the starter motor. It usually has an eyelet on it.
Another ground can be found from the antenna to the frame in the rear of the car (but that one just grounds the antenna - not electrical battery voltage).
I suspect the sparks you saw the other night were weak spots in your spark plug wires. The spark was jumping to ground instead of to the spark plug (which would make it harder to start).
Another ground can be found from the antenna to the frame in the rear of the car (but that one just grounds the antenna - not electrical battery voltage).
I suspect the sparks you saw the other night were weak spots in your spark plug wires. The spark was jumping to ground instead of to the spark plug (which would make it harder to start).
Thread Starter
Le Mans Master
Joined: Nov 2004
Posts: 6,128
Likes: 21
From: North Alabama
Originally Posted by Z-man
I suspect the sparks you saw the other night were weak spots in your spark plug wires. The spark was jumping to ground instead of to the spark plug (which would make it harder to start).
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Thread Starter
Le Mans Master
Joined: Nov 2004
Posts: 6,128
Likes: 21
From: North Alabama
Originally Posted by SteveG75
Check the ground from the engine to the frame by the passenger side mount. That is the only ground from the engine to the frame.
Burning Brakes
Joined: Sep 2004
Posts: 1,167
Likes: 2
From: Ft.Worth Texas
If you have ONE GOOD GROUND you will not have an arc from dipstick to booster. It just won't happen. If you have a bad plug wire I would be really surprised if you have enough energy to spark from wire to dipstick (which is a ground itself) and also continue a spark to the booster.
Pro
Joined: Oct 2004
Posts: 567
Likes: 0
From: Springhill Kansas
Originally Posted by David Ey
If you have ONE GOOD GROUND you will not have an arc from dipstick to booster. It just won't happen. If you have a bad plug wire I would be really surprised if you have enough energy to spark from wire to dipstick (which is a ground itself) and also continue a spark to the booster.
Burning Brakes
Joined: Sep 2004
Posts: 1,167
Likes: 2
From: Ft.Worth Texas
Yes, but isn't the dipstick grounded to the block?
Oh well, who knows whats going on here. Looks like another mystery like the why won't my 383 start when it has gas, spark and compression and the valves are working in time with the crank and the dist is set close enough.
Oh well, who knows whats going on here. Looks like another mystery like the why won't my 383 start when it has gas, spark and compression and the valves are working in time with the crank and the dist is set close enough.
Pro
Joined: Oct 2004
Posts: 567
Likes: 0
From: Springhill Kansas
Originally Posted by David Ey
Yes, but isn't the dipstick grounded to the block?
Oh well, who knows whats going on here. Looks like another mystery like the why won't my 383 start when it has gas, spark and compression and the valves are working in time with the crank and the dist is set close enough.
Oh well, who knows whats going on here. Looks like another mystery like the why won't my 383 start when it has gas, spark and compression and the valves are working in time with the crank and the dist is set close enough.
Drifting
Joined: May 2001
Posts: 1,329
Likes: 12
Lol... Check for a cloth covered ground wire between the frame and the body skeleton near the first mount on the driver side. That should ground your body. Then you have the one for the engine like the others said... with both of those covered, you can move on to another reason for that spark... I've never heard of plug wires jumping like that though.
David: gas and spark ignite if there is combustion, whatever your timing is. If its not even puffing or huffing then you don't have one of the 3 said above. If it is puffing, then play with the timing (Maybe you have your dist. inversed, happens often). To know the dist is in the right spot, put piston #1 at TDC on the compression stroke (Valves closed) and open your dist. It should point at your #1 cable. If its pointing opposite, you got it inversed.
David: gas and spark ignite if there is combustion, whatever your timing is. If its not even puffing or huffing then you don't have one of the 3 said above. If it is puffing, then play with the timing (Maybe you have your dist. inversed, happens often). To know the dist is in the right spot, put piston #1 at TDC on the compression stroke (Valves closed) and open your dist. It should point at your #1 cable. If its pointing opposite, you got it inversed.
Burning Brakes
Joined: Aug 2005
Posts: 1,126
Likes: 0
From: Hudson Falls, N.Y. 76 Vette Modified L-48
Originally Posted by Z-man
I suspect the sparks you saw the other night were weak spots in your spark plug wires. The spark was jumping to ground instead of to the spark plug (which would make it harder to start).
Race Director
Joined: Nov 1999
Posts: 10,643
Likes: 8
From: Foxfield CO 1970 Convertible
Originally Posted by Jclgodale3
No...the plug wires are new. The spark was definetely coming from the handle on the dipstick to the booster. Hence the reason the handle was getting so hot. Or, are you saying a plug wire touching against the dipstick tube?
Melting Slicks
Joined: Dec 2005
Posts: 2,441
Likes: 0
Originally Posted by Jclgodale3
Ok...have the ground from the battery to the frame (directly under the battery) Also have the ground from the engine to the frame. Where else should it be grounded? While starting it the other night a friend noticed an arc jumping from the dipstick handle to the power brake booster. And the handle was getting HOT! Assumption is...it's trying to find another ground. Never had a problem with it starting but don't want to start a fire under the hood either!
Input or suggestions?
Input or suggestions?