Help Please son's '84 vette.

[roger longman]

Hello everyone and a happy new year. Son's '84 vette battery goes flat if left for more than 2 days. This started about 4 years ago,the garage changed the alternator 3 times ! put in a new battery (I have the old one and it's still working just fine in my '88 vette) but the problem seemed to have been resolved. Then 5 days ago it would not turn over after being left for 3 days over the Christmas period. A boost to the battery got it going again and it continues to start when left over night. OBVIOUSLY A DRAIN ON THE BATTERY BUT WHY DOES IT TAKE SO LONG TO GO FLAT? It isn't the interior lights. I'm usless on electrics at the best of times and I have no faith in his mechanic. Can anyone point me to a possible cause. My thanks in advance for any help. Roger.

 

[doublefoxed]

They make High dollar test equipment but here is a simple
back yard mechanic trick..
One 12v automotive bulb
unhook 12 v + terminal from battery.
2 pieces of wire. long... alligator clips on each wire
hook the clip to the bulb and the other end to the disconnected
battery cable. Now hook the other to the battery
now start pulling fuses till the light goes out.. This
will get you close to the source..
If all else fails put a battery shut off on it...

 

[roger longman]

Thanks doublefoxed. But I wonder has anybody had a similar experience and found the cause ? Roger.

 

[JAKE]

I suspect the Digital Dash.

A friend of mine's 85 had the same problem and he ended up putting a battery cut off on his. Unfortunately, he's one of those kind of guys who doesn't take advice well; likes to think he can solve ALL his problems alone. So he never found the cause even though I suggested having his DD repaired. His was all jacked up.

I can tell that you're not like him, though.

What I've come across on a couple of Forums was that the digital dash could often be the cause of the battery drain. Especially if your son's dash isn't working properly (which is often the case in the early C4s), it could well be his dash. And, yes, it does take days for the car to sit for the battery to drain to the point that the car won't crank.

Do the 12v light bulb trick and see if pulling the dash fuse doesn't pin-point the cause.

Hope this helps, and Happy New Year! to all.

Jake

 

[roger longman]

Thanks Jake, the "mechanic" nas told him the battery is draining 200 milliamps,do you think that could be indicative of a dash problem ? I've told him to do what you sujest coupled with doublefoxes method and report back, thanks again fellars. Roger.

 

[vetteoz]

I believe 50 ma is the factory figure.
Any aftermarket alarm system?

Long shot ; unplug the headlight motors and leave over night.That was my drain

 

[roger longman]

Hi everyone, he's been told that 200ma is not enough current to light a bulb,headlamp motors have been disconnected for some while. The dash was replaced about 7 months ago. Does anyone have any further pointers? Roger.

 

[doublefoxed]

well the mill amp draw is not enough to drain it in that few of days
so i would lean to maybe a dead cell in the battery.

 

[Paul Higg]

There are a bunch of drains on a Vette battery. Stereo clock, digital dash, alarm, I'd have to dig deeper in my FSM but I have seen in the wiring diagrams a bunch of them. Also, a TINY short to ground can cause it AND dirty terminals. If the battery is old I would be willing to bet it is a bad battery.

If your going to keep the car buy an FSM. Then I can help you all day with wiring because that's all I did for 30 years.

Paul

Welcome to the forum!

 

[minifridge1138]

It could be a dead cell in the battery.
Personally, I would start there because it is a lot easier to replace a battery than a dash.

Since the dash was replaced a few months ago, it is possible that there is a problem there.

Good luck!!!

 

[DPC Racing]

Seen this problem alot,200 mil amps will not light the test light and take about 2or3 days to drain battery[when fully charged] stock 84 has about 25 mil amp drain.It can be anything draining it,the first thing you need is a meter to check mil amps.Hook it up like you would the test light and start pulling fuses like somebody else said,I even had the ecm draining the battery before,the dash anything. Just disconnect one thing at a time and watch the meter.
Good Luck

 

[roger longman]

Hi everyone,just an update. We haven't been able to track down the cause yet but as the car is a daily driver he's putting up with it for the time being. Another more pressing problem happened to him, he had Nan Kang tyres put on about 2000 miles ago,the other day, at about 45mph, the rear n/s disintegrated. I had it flat bedded to the tyre place where we discovered the other rear was about to go. They put on a couple of loaners whilst sending the others back to the distributor, who said alignment was the problem. His "mechanic" had it checked and a minor adjustment was made. HOWEVER, when I checked his computer alignment record it states; " Chevrolet: Corvette : 1994-96". His is a 1984!Does anyone know if this could cause the problem and any experience with these tyres? Roger.

 

[Paul Higg]

How old were they? There was a great article on old tires exploding. I don't know if the model year makes a difference but I have seen the age of a tire doing this. You do not want a tire six years old or older. There is an oval on the tire that tells you the year and month it was made.

 

[So Bay Vetter]

Does anyone know if this could cause the problem and any experience with these tyres? Roger.

Holy Cow! hnoesIf it was alignment, I would think there would have been some really noticable tread wear preceeding that kind of failure. If you have the alignment print out, It should have the "actual" - "before" - and "specified range" listed. It would have to be waaaaay outside Spec range to shred a tire. Unless someone's smokin' the tires a lot, I think the tire company is pulling a CYA on you. Just a suggestion; you might take the printout to Greg at Firestone on Sepulveda in Manhattan Beach and get his view. He's always been a straight shooter with me.

 

[roger longman]

Thanks Paul and So Bay. The tyres were only a year from manufactured date when he bought them. My main concern is that the alignment sheet states "Chevrolet Covette 1994-1996" but his is a 1984. From what I've read on the forum Vettes seemed to change alignment almost every year so how can a1994 apply to a 1984 ? Also I wont be recomending this make to anyone and wonder whether other members have had experience with them. Roger.

 

[Paul Higg]

You're welcome. I have Khumos for what it's worth. I like them.

 

[So Bay Vetter]

While there were several shock/sway bar changes over the course of C4 production I think, from an alignment standpoint, the mechanics were pretty much the same. Even if there were differences in the alignment data it could not have been much. I've had my '96 aligned at Dick Guldstrand's shop in Burbank and they used angle iron and a tape measure! It might be worth a second opinion (Greg @ Firestone). In any event, I find it hard to believe that alignment caused your son's tyre to shred. Thank God he wasn't doing 130 at a track day when it happened!

 

[Paul Higg]

So Bay, I agree, I have done a lot to the throw off the car's alignment and do not have the scratch to have a proper alignment done but I will soon. Anyway, I think all it will do is cause slight uneven wear on the tires. Personally, I think it was a defective tire. And, thank GOD (sorry non-Christians) he didn't get hurt. That video I saw about older tires exploding was a real eye-opener. I have had mine up to 130 a bunch of times but now I only go 5 over with cruise (honest!) I have too many years ahead of me to get killed in a wreck and I know a lot of people who have died in wrecks.

Paul

 

[roger longman]

The tyre actually ended up as 3 separate circular sections,I've never seen anything as bad ! My rack and pinion and transmission were replace by Dick Guldstrand whilst he was on Jefferson. The man is a genius with Corvettes and one of the nicest people you could ever meet. He also worked on my sons' car after moving to Burbank but I can't remember what he had done. I'm still wondering if anyone has had experience with these Nan Kang NS1 tyres my son had not been over 90 mph on them! Roger.

 

[So Bay Vetter]

I think you're right about defective tires Roger. The Company would be in a world of financial and liability hurt if they admitted the defect thus, the "alignment" story. I've viewed a bunch of threads here and haven't seen much on Nan Kang, nor have I seen any at track day. Maybe they're more of a "tuner" tire and are ill equiped to handle the torque of a V8. . . Hmmmmm . . .