I have a 73 240z. The battery has been draining even wth the enigine running. The ammeter sows a discharge when the vehicle is running. I have already had the alternator checked and have replaced the voltage regualtor.

The problem seems to be that the power from the alternator is not reaching the electrical system. Haynes and Chilton both mention fusable links that protect the starter and alternator, but I cannot find them. Can anyone assist me with this. I am open to any other suggestions as to what the problem might be also. I'm sure it is probably something annoyingly easy and probably obvious too.

Thanks,

Rich

First, check the connections at the battery. Make sure they're clean and that they are tight. Remove, clean and replace. Visual inspection is NOT enough.

Second, check the negative pole grounds. Too many times this simple check has caused many problems. The negative pole on the battery should have a wire going directly to the firewall. Remove, clean and replace. Visual inspection is NOT enough. This can't be said too many times.

Third, early Z's had ONE fusible link...going to the starter from the harness. Later model Z's (and yours may be one since it's a 73) had a fusible link box located on the firewall. These links looked like wire loops going up and back into the same box they came out of. Might not hurt to remove, clean the ends and replace. Did I mention you should remove, clean and replace. Visual inspection is NOT enough.

Lastly, connect a trouble light between the negative pole on the battery and it's connector. With the ignition OFF as well as all systems in the car OFF (except the clock, presuming it's working) you should not have ANY glow in the bulb. If there is ANY glow, you have a current draw on the battery when there shouldn't be any.

Start disconnecting relays and other connectors one by one, and see if the glow disappears. If it doesn't, then re-connect and try the next connector. Once you kill the glow, you found the circuit that has the draw. Next step is to use the wiring diagrams with the wire color combinations to determine what it was you disconnected.

HTH

E

I have tried everything you suggested. The only exception is that I don't have a trouble light, so I used my multi-meter. It registered a 5 mamp discharge which I think might just be the clock on the radio(aftermarket).

Is there anything else I can try.

I also did not find the fusable links. I checked the firewall the only thing that I found there of the wiper relay.

Thanks

Rich

Wiper Relay? Not there that I'm familiar with. The wiper relay is ON the motor.

You can substitute a plain old 12v light bulb for a trouble light. In fact some trouble lights are just that, a bulb with wires attached.

Can you post a picture of this wiper relay? That may be the fusible link box I was referring to.

But not charging still points to the Voltage Regulator.

When you checked the battery cables, did you check BOTH ends of the cable to ensure it was making good contact?

Anyone else with ideas?

E

Do you have an automatic? I think I know the 'relay' he is talking about. I have one too and no one seems to know what the hell it does.

I recall a Seat Belt Inter-Lock Relay in that position in the later 72's but I hadn't considered that.

E

But not charging still points to the Voltage Regulator.

Just replaced voltage regulator

When you checked the battery cables, did you check BOTH ends of the cable to ensure it was making good contact?

I don't mean to sound silly here, but if the car starts, doesn't that mean I have a good connection on both ends(the battery and the starter)?

The ammeter(in dash) shows a discharge when the car is running. If driven a sufficient amount of time the car starts to cut-out because the battery is the only electrical supply.

The voltage regulator and alternator have both been replaced and the problem persists.

Any suggestions?

Thanks

Rich

maybe check the continuity of the wires connected to the alternator/ voltage regulator. also check for corrosion on them.

If you have an ohms meter, check the wire that comes from the back of the alternator to the harness.. Ocassionally, the wire is actually a fusable link, which were present on some 240Z's. Give your wires a tug. Some wires can burn on the inside of the sheath and still look like an intact wire. The ohms meter will tell you the same thing.

Some glass fuses look totaly good until you test them and find that the solder has flowed away from the fuse from overheating.

The problem is with the alternator and its wires, somewhere.

Dave.

...I don't mean to sound silly here, but if the car starts, doesn't that mean I have a good connection on both ends(the battery and the starter)?

The car starting DOES mean that you have a good connection between the battery and the starter. However, if that were the ONLY reason for discharging the battery, then I wouldn't have mentioned the OTHER grounds.

I had a car that KILLED 4 Die-Hard Batteries in a period of about 6-8 months. Since I worked at the mall at the time, I got a lot more leniency than an off the street customer, but even with me they finally sent me to a "specialist". This is after having replaced a voltage regulator and having had the alternator pass each and every one of Sear's tests EACH time they replaced the battery under warranty. The electrical specialist removed ONE screw, sanded down the metal where it was and replaced the screw. Cost me $20 bucks and it fixed the problem. Never replaced a battery in that vehicle again. The problem? No ground to the body chassis. All of the vehicle's electrical components NOT attached to the engine were draining the battery because their load wasn't registering THROUGH the battery but rather through the engine. The regulator just kept the switch to the engine and NOT to the battery. This is simplistic, but it illustrates my point.

The problem you are having is that not enough juice is being sent to the battery...OR...you're not producing enough juice.

That points to either the Regulator or the Alternator.

One of them is NOT functioning ... OR ... is not connected properly.

2¢

E

Try checking the connections inside the plug to the voltage regulator. The same thing happened to me and I could not figure it out. I had to put the car on a trickle charger every night and sometimes she would die while out driving at night. One of the tongs in the voltage regulator was missing and the charge was not going through to the battery, but everything else was working properly. Just a suggestion. I also have a '73 born on October '72.

The '73 does not have fuseable links.