Dash Wiring 12 volts not right
Thread Starter
Instructor
Joined: May 2011
Posts: 191
Likes: 1
From: Orange Ca
Dash Wiring 12 volts not right
Help...I am totally stumped. I replaced the inop Autometer electric fuel pressure gauge with a new one and it nearly caught fire. I sent it back for a new one thinking it was defective. I wired the second gauge directly to the battery just to be sure the gauge worked. All was fine so I connected the gauge to the red wire the original inop gauge was connected. When I turned the key on (electric fuel pump) the gauge needle went down below zero the stop. I immediately turned off the power and checked the voltage. Sure enough 12 volts with the key on. I wired the gauge back to the battery to make sure it was working ok...it was (thank God). I tried it again but the needle would go south not up to the 40 psi I am looking for. I put the red wire of the gauge to the fuel pump relay 12v and it works fine. I have had the car since May and have only driven it a few miles. It has been highly "Bubba'ed" with disconnected wires everywhere. I have no problem installing a new wiring harness but would like to understand how it could be different on from one wire to the other...any help would be greatly appreciated...Brent
Melting Slicks
Joined: Aug 2010
Posts: 2,207
Likes: 26
From: Ocean County NJ
Good luck Brent. I also bought my 68 in May and have had electrical gremlins from nose to tail. Bubba spliced the heck out of the network. Got tired of chasing ghosts in the machine, so I bought all new harnesses and will start the upgrade after the holidays. Not that I want to do it, I need to.
Melting Slicks
Joined: Aug 2008
Posts: 2,200
Likes: 3
From: Lehigh county Pennsylvania
Racer
Joined: Nov 2011
Posts: 319
Likes: 12
From: South Chase WI
Sounds like perhaps a ground problem, your gauge is acting as ground / negative for much more load than it should be seeing?
Can you check the amp draw at the gauge connections when energized, and start using things until the meter jumps when it should not?
Can you check the amp draw at the gauge connections when energized, and start using things until the meter jumps when it should not?
Thread Starter
Instructor
Joined: May 2011
Posts: 191
Likes: 1
From: Orange Ca
Good luck Brent. I also bought my 68 in May and have had electrical gremlins from nose to tail. Bubba spliced the heck out of the network. Got tired of chasing ghosts in the machine, so I bought all new harnesses and will start the upgrade after the holidays. Not that I want to do it, I need to.
http://www.ronfrancis.com/prodinfo.asp?number=GW-34
and this for the 12 volts system
http://www.ronfrancis.com/prodinfo.asp?number=FB-44
I am also considering this:
http://www.isispower.com/start.html?...FWU0Qgod7xiQSQ
I have researched through the forums the benefits of the ISIS system but have not seen many others with experience using it. Looks pretty neat.
Thread Starter
Instructor
Joined: May 2011
Posts: 191
Likes: 1
From: Orange Ca
Just using the wire that the bad gauge was using. Here is another odd thing. I tried connecting the red wire of the new gauge to the 12 volt connections on the other gauges ie. fuel level, oil pressure etc...same thing..no can do. As soon as I touch the red wire of the new gauge to any of the hot terminal of any gauge the new gauge pegs down.
Thread Starter
Instructor
Joined: May 2011
Posts: 191
Likes: 1
From: Orange Ca
