330GTC Electrical Question

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tinbender
Posts: 29
Joined: Thu Jul 08, 2004 9:38 pm
Location: Raleigh, NC

330GTC Electrical Question

Post by tinbender »

All this started as my electric fuel pump would not operate. I have around 10 volts at the pump, so I start checking around. I have around 10 volts at the fuse for the pump and around 10 volts at the dash switch for the pump. I have seen the suggestion to clean the 4 way connection on the fuse board, so I do this and I have 12.8 volts at this junction and I have 12.8 volts at the ignition switch on the wire that feeds the ignition switch coming from this 4 way. I check the wires coming out of the ignition switch and all of them that are hot have around 10 volts. So I think the contacts in the ignition switch are bad. But then I happen to check the wire feeding the ignition switch while the switch is turned on and it only has around 10 volts now where it has 12.8 with the ignition switch turned off. I check back at the 4 way junction and the wires here only have around 10 volts when the ignition switch is turned on and 12.8 when the switch is turned off. The battery has 12.8 volts with the ignition switch off and falls to 11.8 volts with the ignition switch on. I check for draw and have 9 amps of draw with the ignition switch turned on (about .25 with it off) so I start pulling fuses and the ignition fuse is drawing about 5 amps and the regulator fuse is drawing about 3.5 amps. Could this draw be causing the voltage drop?
Any ideas?
Regards, Terry Phillips 330GTC #9411
John Vardanian
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Re: 330GTC Electrical Question

Post by John Vardanian »

Get a read read between the fuel pump terminal and the negative terminal of the battery, see if you still get 10 volts.

john
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tyang
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Re: 330GTC Electrical Question

Post by tyang »

Hi Terry,

The GTCs have a relay that clicks on when the ignition switch is in key-on position. Try to find that relay to see what it's drawing at that junction.

Tom
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enio45
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Re: 330GTC Electrical Question

Post by enio45 »

early cars, it is the CEAM box on the lower left side of the fuse board.....has 5 terminals on it (i believe)

that turn on the circuits to other areas of the car - like the 4 point distribution block....
Ed Montini
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Jimmyr
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Re: 330GTC Electrical Question

Post by Jimmyr »

If you have 12.8 volts into the 4 way terminal block and 10 volts out from there it does say there is a voltage drop in that block. So remove all the wires from that block including the two jumper wires, clean everything; wires, jumpers, screws insides etc. This jumper block is a constant problem for all models that use them. The corrosion is a result of the 3 different metals in contact with each other and moisture that cause a chemical reaction that promotes the corrosion and thus the voltage drop.
Steve Meltzer
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Re: 330GTC Electrical Question

Post by Steve Meltzer »

is there a fuse in this circuit?? if so, not clearly marked on the panel covers. thanx steve
steve meltzer,
"I've spent all of my money on wine, a beautiful woman, and stunning cars. Then, squandered the rest."
tinbender
Posts: 29
Joined: Thu Jul 08, 2004 9:38 pm
Location: Raleigh, NC

Re: 330GTC Electrical Question

Post by tinbender »

Steve,

If you mean the electric fuel pump circuit, there is a fuse. It is the bottom fuse on the passenger side fuse board and on my car it is labeled fuel pump along with stop and rear defrost. It is fuse number 8 in the owners manual.
Terry
Regards, Terry Phillips 330GTC #9411
Steve Meltzer
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Re: 330GTC Electrical Question

Post by Steve Meltzer »

thanx Terry, our cars weren't too far from each other at assembly. steve GTC 8995
steve meltzer,
"I've spent all of my money on wine, a beautiful woman, and stunning cars. Then, squandered the rest."
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