Short Somewhere?

Gotta love that wiring . . .
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davery
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Your car is a: 1985 Spider
Location: Ohio

Short Somewhere?

Post by davery »

So I have all the gauges and dash switches removed to replace the wood/fake wood sections. The cars hasn't really been driven in about 3 months. I tried to start it on Saturday and it wasn't getting enough juice to turn over. I jumped it and it started right up and I let it run about 10 minutes. Today I went out to start it and the battery is dead again. I put the trickle charger on it and about ten minutes later tried to start it again. It must have tripped an internal fuse in the trickle charger, as the charger went off. I repeated this and it happened each time. So it appears I have a short somewhere in the ignition or is there something I am missing with the gauges and switches removed? I did remove the ignition connection to the key chime, but I doubt that would be the issue.
Don Avery
Dayton, OH/Sarasota,FL
1985 Pininfarina
2011 Eos
2012 Mercedes E550 Cabriolet
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aj81spider
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Your car is a: 1974 Fiat 124 Spider
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Re: Short Somewhere?

Post by aj81spider »

A trickle charger won't charge your battery in 10 minutes and when you try to start it you are putting a low impedance across the charger (the starter) that would trip any overcurrent protection. Your description of symptoms wouldn't indicate there is a problem.

Let it charge overnight, or jump start it with another battery. It may be you have a short, but what you describe wouldn't lead me to that conclusion.
A.J.

1974 Fiat 124 Spider
2006 Corvette
1981 Spider 2000 (sold 2013 - never should have sold that car)
davery
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Your car is a: 1985 Spider
Location: Ohio

Re: Short Somewhere?

Post by davery »

aj81spider wrote:A trickle charger won't charge your battery in 10 minutes and when you try to start it you are putting a low impedance across the charger (the starter) that would trip any overcurrent protection. Your description of symptoms wouldn't indicate there is a problem.

Let it charge overnight, or jump start it with another battery. It may be you have a short, but what you describe wouldn't lead me to that conclusion.
There has been a couple times where the car wouldn't start where I have used the trick lie charger to get a little extra to turn the car over. But not this time. Anyway, I will give it a go tomorrow.
Don Avery
Dayton, OH/Sarasota,FL
1985 Pininfarina
2011 Eos
2012 Mercedes E550 Cabriolet
DieselSpider
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Your car is a: 1978 124 Spider with Isuzu Turbo Diesel

Re: Short Somewhere?

Post by DieselSpider »

If the battery is really dead then a trickle charger won't be able to provide enough amperage to start a car.

It takes about 1 kilowatt of power to start a gasoline engine and 2 kilowatts for a diesel.

A trickle charger will need to be on 12 to 48 hours to bring up a flat dead battery far enough to start a car if the battery is still in good shape.

You need a jump starter/charger with at least a 50 to 75 amp capacity to be able to start the car in 10 minutes when the battery is close to flat dead.
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RRoller123
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Re: Short Somewhere?

Post by RRoller123 »

It sounds like the wires that were attached to all the gauges that were removed may be shorting out somewhere and draining the battery.
'80 FI Spider 2000
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davery
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Re: Short Somewhere?

Post by davery »

RRoller123 wrote:It sounds like the wires that were attached to all the gauges that were removed may be shorting out somewhere and draining the battery.
Could be. I don't know if it's related, but the headlights are not working.
Don Avery
Dayton, OH/Sarasota,FL
1985 Pininfarina
2011 Eos
2012 Mercedes E550 Cabriolet
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RRoller123
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Re: Short Somewhere?

Post by RRoller123 »

Tape up the exposed ends of all those loose wires and see if it helps?
'80 FI Spider 2000
'74 and '79 X1/9 (past)
'75 BMW R75/6
2011 Chevy Malibu (daily driver)
2010 Chevy Silverado 2500HD Ext Cab 4WD/STD BED
2002 Edgewater 175CC 80HP 4-Stroke Yamaha
2003 Jaguar XK8
2003 Jaguar XKR
2021 Jayco 22RB
2019 Bianchi Torino Bicycle
davery
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Re: Short Somewhere?

Post by davery »

RRoller123 wrote:Tape up the exposed ends of all those loose wires and see if it helps?
Not really any loose wires that I can think of, just loose plugs.
Don Avery
Dayton, OH/Sarasota,FL
1985 Pininfarina
2011 Eos
2012 Mercedes E550 Cabriolet
TX82FIAT
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Re: Short Somewhere?

Post by TX82FIAT »

It sounds like RRoller is on to something. If you do not have wires hanging around while doing a dashboard replacement you are in much much better shape then i was when re-wiring my dash. Try fully chanrging the battery and letting it sit out of the car for a couple days, re-install and start car. If the battery holds charge after sitting for a couple days and starts the car right up it tells me you have a parasitic draw. A lose end of a wire is creating a circuit drawing down the battery OR some live wire has some exposure completing to ground (hot to ground). the popped fuse indicates this is possible. You may be in the trace to find game. Start by tracing the circuit where the fuse blew. With the dashboard out you should be able to do a good visual inspection of all wires in and out of that fuse position to thier components.
Buon giro a tutti! - enjoy the ride!

82 Fiat Spider 2000
03 BMW M3
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davery
Posts: 806
Joined: Sun Apr 15, 2012 8:51 pm
Your car is a: 1985 Spider
Location: Ohio

Re: Short Somewhere?

Post by davery »

TX82FIAT wrote:It sounds like RRoller is on to something. If you do not have wires hanging around while doing a dashboard replacement you are in much much better shape then i was when re-wiring my dash. Try fully chanrging the battery and letting it sit out of the car for a couple days, re-install and start car. If the battery holds charge after sitting for a couple days and starts the car right up it tells me you have a parasitic draw. A lose end of a wire is creating a circuit drawing down the battery OR some live wire has some exposure completing to ground (hot to ground). the popped fuse indicates this is possible. You may be in the trace to find game. Start by tracing the circuit where the fuse blew. With the dashboard out you should be able to do a good visual inspection of all wires in and out of that fuse position to thier components.
I have the dash back in now, but the gauges and switches are not. I think what I am going to do is put the driver's seat and the steering wheel back in and drive it around for several minutes. Give it a chance to charge and then let it sit a couple of days (as you suggested). The problem now is I made these pigtails to relocate the the small gauges to the upper center console. As of today they are hanging around and it is possible they could be creating a short.
Don Avery
Dayton, OH/Sarasota,FL
1985 Pininfarina
2011 Eos
2012 Mercedes E550 Cabriolet
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aj81spider
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Re: Short Somewhere?

Post by aj81spider »

Depending on the level of charge in the battery it is going to take a lot longer than a few minutes of driving to recharge a discharged battery. A fully depleted 70 Amp hour battery needs to be charged for a long time on a typical 6 amp charger.

If you are doing charge/discharge testing you need to make sure it's really fully charged (i.e. put it on a charger overnight).

Here's an article on battery charging that provides some more insight.

http://batteryuniversity.com/learn/arti ... id_battery
A.J.

1974 Fiat 124 Spider
2006 Corvette
1981 Spider 2000 (sold 2013 - never should have sold that car)
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