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How do you find a battery drain

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PATR8

PATR8

Jedi Knight
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OK, I have the 8 running but the battery is dead every morning. I have checked all the usual suspects such as lights and such and am out of ideas. HELP
 
Pat easiest way around it immediately is put a kill switch on the battery and turn it off when parked...doubles to save any open draw on battery and also as a theft deterrent...I put the switch up under dash....
 
I don't know anything about how an 8 is wired; but the usual approach is to divide and conquer. Put a test lamp or something in series with a battery connection, then start disconnecting things until it goes out.

Many years ago I had a German car that would drain it's battery only sometimes ... eventually discovered a relay with enough dirt and salt on it's phenolic baseplate that it would turn itself on when dew condensed on it. Only found it by good luck, I happened to walk by the car one night and saw the indicator for the rear window defogger glowing.
 
last time i had a battery drain on my tr7 fhc the alternator was bad. every time i connected up the wire to the instrument panel my meter picked up a short. since your tr8 probably has the same model alternator try that. btw, i subsequentially put in a 105 amp alternator from a '94 camaro. it was clocked correctly for my tr7 and haven't had any problems with it.
 
I actually got a GM alternator that the TR8 car club of America showed me how to swap in, but I think you hit it on the head, will play with it tomorrow evening. I am thinking I may have thrown an extra wire on the battery link in the fire wall. Hmmmmm..... I am sure it is a self induced problem which only upsets me more
 
i found a pleasant surprise in my tr8 parts car. the rear control links have new hardened bushings installed, links look new also. off they came and into my dhc. slowly my parts car is being dis assembled.
 
TR3driver said:
I don't know anything about how an 8 is wired; but the usual approach is to divide and conquer. Put a test lamp or something in series with a battery connection, then start disconnecting things until it goes out.
Click to expand...

Tried 'n true. Sometimes the "old ways" are the best ways. /bcforum/images/%%GRAEMLIN_URL%%/wink.gif
 
To make life as easy as possible, do as Randall suggests. However, begin first by pulling fuses one at a time. You'll then isolate a circuit. Then begin eliminating each branch of it, one at a time.

At the risk of stating the obvious, but many do not know, when he says to put a test lamp in series, this is the procedure. Disconnect the negative terminal. Connect a simple test lamp between the negative post and the cable.

The light will glow (brightness depends on amount of drain). When you pull the fuse from the offending circuit, the lamp will go out. You now know which circuit is involved. Then replace that fuse and begin to (for example) unplug lamps one at a time until the test light goes back out. At that point you've found the particular circuit branch. Now you need only to decide if it is the component or the wire to it.
 
Well the battery drain as become a more involved problem. The car will start and run for a little, get up to tempature and then shut off. The car feels like the battery is dead or vapor lock or something. It seems like maybe the ground is not good, will strip the ground connection tomorrow to see if it may be the problem. It might also explain the lights not wanting to go up and down. If it is not the ground I will be back to beg for help cause I am at wits end
 
do your guages seem to indicate normally. and the emergency flashers do they seem normal? i have seen ground problems give indications in those two areas.

the warm up and shut off seems like a different problem. maybe the coil or ballast resistor is heat sensitive. is the coil on the firewall or front bulkhead on your car?
 
The emergency flashers make noise but do not work but the turn signals do. I have the coil located beind the radiator but it continues to spark after it shuts it self down ( I Have a MSD and when you seperate the wires you can hear it spark.)

SOme one suggested that a bad ground might be the cause of the head ligts popping up and down and when I did a quick brush of the negative connection off of the battery it started right up (but shut back down when it hhit tempature)

It has me pretty befuddled and I am going on vactation tomorrow so I have some time to think of it but the guys on here help allot. Thanks
 
PATR8 said:
I Have a MSD
Click to expand...
FWIW, I've had 2 different MSD units fail now with temperature issues. The MSD 5 on the motorhome would quit working only when it got hotter than usual (like climbing a hill, caused by hot air from the radiator blowing against the firewall mounting). The MSD 6A on the Chevy would quit for just a minute or less while warming up, then be fine for the rest of the day.

If you send a unit back to MSD, they will repair it (if it can be repaired) for a fairly nominal charge (less than 1/2 retail price). They also upgrade the unit to the latest design (for that unit). If it cannot be repaired (one of mine had a charred circuit board), they will sell you a new/refurbished unit for about 1/2 retail price.
 
It is not the MSD unit, I still have spark to the distributor after it shuts itself down. When I bought my original 8 I sent the MSD box in and they did a great job of cleaning it up and fixing the wires the DPO had cut and butchered up, all for free except a $20 shipping fee
 
Well a lot of talk,but you have never said what the voltage reads on your dash gage. It should be at least 13 to start up and 14 when running.... Otherwise you have a battery/alt problem.Remember batterys can drain themselves!!
MD(mad dog)
 
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