Hello all, I have been helping a friend with a 1992 Honda Accord that has an odd battery/charging issue we can't figure out. Before going into details I will try and summarize what has been done to the car already. This car is not modified, has 200k miles, and has no aftermarket accessories or anything sketchy (that I have seen). Honda replaced the alternator recently, then when that did not solve the issue another shop replaced it. Honda told him that there were no issues with his car after taking it back, and the tech quoted his "26 years of experience" and refused to listen.

He also had a new battery just installed, and the local auto parts store checked the alternator and battery with their tool showing both were alive and well.

This issue has been a pain and the car isn't really drivable, due to how it slowly drains and then dies. I figured (before he told me all of this) that the alternator wasn't charging and that the car should be able to run off the alternator alone. I suggested running the car without the AC ( he already did this), which did allow it to go for about a week, but it still died during that time.

I have an 89 Volvo 240 and work on Volvo redblocks, so this is something a bit different but I have tried to treat them the same. Does anyone have any suggestions about what I should be looking at or checking on this car? Sometime we will be checking more from loose connections, degraded wires, etc. I have also heard about an Electronic Load Detector on Honda's, but haven't found info on a 1992 accord and if it even has one. There was also a post about some sort of relay located under the drivers dash, somewhere to the left of the steering column. With Volvo I am very used to resoldering relays so was looking into this as well, but wasn't sure what this relay was.

 

Chasing these are always a pain, especially a low drain like this.

There's a scientific way, which can take some time, which is to have the car off, and start checking to see what voltage is still coming through on the car. This means checking all the things that should be "off" but still have 5 or 12 volts to them. This will not be fast, since the only way I can think to do this is to walk through every fuse, check voltage and see if it should be zero with the car off. When you hit the item that is showing voltage when it should be off, you've found your short or bad relay. If you've already removed the obvious, such as the alternator, it gets really hard.

You could also go about this another way, with some broad strokes used to help. Remove all the fuses from the car you can find, wait a day or two, put them back in and see if the car starts. If it does, you know it's something related to the items in that fusebox. If it doesn't, at least you know it's nothing related to the items in that fusebox. If it is related to the items in the fusebox, put half the fuses back in, and wait again a few days then see if it starts. If it doesn't start, you've narrowed it down further to half the fuse box which now have fuses in them. If it does start, you know it's related to the other half you haven't put in yet. Keep putting in half and half of the half until you have narrowed it down to the final one. Yes, this will takes days and days, but it's a way that should work, since almost everything has a fuse to it.

If it turns out it's not related to that fusebox (meaning you pulled them all and the car still won't start), then go to the next fusebox and do a similar item. To me, that's the fastest way to narrow down where the hell the problem is coming. Checking loose wires and such will take forever otherwise unless it's obvious. Which it doesn't sound like.

 

There is a difference between the alternator not charging with the car operating vs. an excessive parasitic drain when the car is off.

Under-dash Fuse No. 2 (15A) supplies the ignition input that turns on the alternator/regulator assembly. With the ignition switch in the RUN or START position, power from Fuse No. 2 goes through the Blk/Yel wire to the alternator. If power doesn't go through the Blk/Yel wire, the alternator doesn't charge.

 

Died while driving?

 

Correct, it has died while driving twice.

 

Dies while driving sounds like cable is not grounded well, broken, or loose to battery. Are you able to put a meter on the battery while driving to see where it is when it dies?

 

And once it dies, the battery is confirmed depleted?

 

Sorry about the delay, but yes the battery is depleted. It has to be jumped off to go again, then it's fine for a good while until the headlights are needed. I don't know how long he's able to drive it with the lights on, but I know it's not for anything more than short runs in town.

The other day we were looking at it again, checking for loose wires and checking the wire plugs. I was told by the owner that the car charges fine and charges when hooked up to the computer, but once any load is turned on (lights, AC, even the radio), the computer shows a failure for the alternator or the voltage regulator. It's a bit difficult to really work with a car that isn't mine but I've been out trying to get any info or pointers.

He also said a family friend offered to wire the alternator directly to the battery so it will always charge. I've never heard of this so a friend and I weren't really able to give any feedback on that idea. I don't know enough about electrical systems to really help in that area, but it sounded kinda odd. Another thing that was suggested was to have the car running, then pull the battery cable off and see if the car keeps going, then if it does turn on the lights and see what happens. Shouldn't that really kill any car?

I was also told in the past to never pull the battery cables off a car that had an ECU, and that pulling the battery cables while a car is running is a trick that will damage fuel injected vehicles.

 

Advise your friend to never turn to that "friend" for automotive advice again.
Correct. That battey absorbs harmful transient spikes from the charging system. Do not take it out of the loop.(In fact the battery itself becomes a load on a running vehicle, removing it may very well create a large spike)


Sounds like a faulty alternator, or possible a poor ground issue.(battery cable...etc)