94 300Zx Draining battery's Major Gremlin!!!

When is it dead and what conditions.. You say it "produces a charge", so I assume it's around 14V with everything turned on and the car at 2000RPM?

Steve,

The charge is at 13.8 volts at 2000RPM, I double checked before replying. I drove the Z last Wednesday, it sat in the garage till Monday, dead battery again on Monday. I recharged the battery and cranked it Tuesday afternoon. All switches and interior lights were turned off.

I also, pulled the 20amp fuse to the ABS brakes. Is there a relay for ABS, if so, where ? Not sure which relay, the outside of the fuse panel has a diagram and labels, but the fuse is the only thing labeled for ABS. What I read online is that sometimes the ABS will not turn off after the engine is shut down and that may draw down the power.

Also, at night, the headlights are bright and a weak alternator would cause the lights to dim when gas pedal is released. Any help is greatly appreciated. Thanks.

Wild-Bill

Steve,

The charge is at 13.8 volts at 2000RPM, I double checked before replying. I drove the Z last Wednesday, it sat in the garage till Monday, dead battery again on Monday. I recharged the battery and cranked it Tuesday afternoon. All switches and interior lights were turned off.

I also, pulled the 20amp fuse to the ABS brakes. Is there a relay for ABS, if so, where ? Not sure which relay, the outside of the fuse panel has a diagram and labels, but the fuse is the only thing labeled for ABS. What I read online is that sometimes the ABS will not turn off after the engine is shut down and that may draw down the power.

Also, at night, the headlights are bright and a weak alternator would cause the lights to dim when gas pedal is released. Any help is greatly appreciated. Thanks.

Wild-Bill

13.8 volts is low. It should be between 14.2 and 14.5 volts at 2000 RPM. 13.8 volts is the float voltage of a lead acid battery. The battery cannot fully charge at that voltage level.

Do you have a multimeter? (If not, they're inexpensive.) Disconnect the positive battery lead and put the multimeter in series between it and the positive battery terminal (multimeter set to read amps). With all accessories turned off, only a very small current will be drawn to keep the clock working, the memory up for the radio presets, etc. This current should be on the order of 10 mA or less.

If you see a heavier current flow, something is wrong. Start pulling fuses until the heavy current flow stops. The last fuse you pull will be the one feeding whatever is having a problem. If you pull all the fuses and there is still a current flow, disconnect the positive lead to the alternator. If that stops the current, you have a bad diode in the alternator.

Not necessarily.

Gary

Gary,

I'll pick up a Multmeter, I'm familiar with the tool, but its one of those gadgets every guy likes to have but never buys until after its needed. Bought a torque wrench to reinstall seats recently.

Do you or anyone else know where the ABS Relay is located ? Its not under either of the panels under the hood, but there's a panel behind the passenger seat attached with velcro. I see wires and a device I'm not familiar with, so I have not touched it. Thanks.

That's low, it should be over 14V. But not sure if that's -the- problem. Did you check it with EVERYTHING turned on?

Get a test light (not a Volt ohm meter), disconect the negative cable and put the test light between the battery and the cable. If there is a drain, the test lamp will light. If so, start pulling fuses till you find the drain.

You'll find the meter useful for a lot of things once you have it.

That I don't know.

Gary

Hey WildBill66, no need to worry. I just had the same problem. My Z keep draining a new Optima battery! Yeah you can put all the guages to check the output but my guess is it just isn't putting out enough juice when you drive it. My lights didn't dim either and the whole shot just like you describe. I took it in and the alternator was replaced and WOW no more drainging problems. NONE. I run a lot of stuff on mine but they will check out fine but just not put enough juice back in to keep it the battery from draining. try it. it was worth the 400.00 to replace it.

Mine had the SAME issues. Everything checked out ok same as yours. Your alternator just isn't putting enough juice back in. I changed mine out and it is great now. No more drained battery. Same exact problem as yours. Don't waste your time just replacce the alternator.

Mine had the SAME issues. Everything checked out ok same as yours. Your alternator just isn't putting enough juice back in. I changed mine out and it is great now. No more drained battery. Same exact problem as yours. Don't waste your time just replacce the alternator.

MarksZ,

I pulled the fuse to the ABS Brakes and everything is working okay for now. I can get an alterntor for $179.00 but installation is a bitch since the unit sits near right wheel and the steering rod has to be disconnected.

I have 91,000 on my Z so the alternator is something I'll have to deal with evetually. Thanks.

well wait it out but I did teh same. Yeah I just had tehm change mine out for the money it was worth missing out on the headache. I still say it is your alternator but up to you. mine was HELL until I changed it. I ahve a EGR (so they tell me) acting up on mine. misses between 2,000 and 3,000 rpm's. I think I am going to take the intake off since it needs to be done to get the the EGR. go figure 100.00 part and 1,100.00 to fix it if I let them do it. damn!

You'll find out why they want so much...

And no the EGR valve itself is bolted to the back of the engine block right above the tranny! I don't see how you can chane it without removing the gearbox. You probably do have clogged EGR tubes which do require the upper intake removal. That's a -FUN- job! :-)