Intermittent power loss

[waller]

Hi all

I have a 78 Beetle that is normally pretty reliable. This morning (it's been parked since last night), I got in and started and noticed it was having a little trouble, but started up fine as usual. Drove it just fine 5 miles, parked and went into a store. When I came out, it was like someone left the headlights on all night and it wouldn't start up.

My wife came and boosted me, it started right up. I've turned it off and on again a few times since then and no issues at all. I don't want to get stuck on my own somewhere, what gives or what should I check?

Also my GEN light sometimes come on right away before starting, sometimes it doesn't but if I wait a minute it eventually shows up (not sure if this is related but thought I'd mention it)

Ryan

[Nicholas D]

How old is the battery? That would be the first thing I'd check. Any auto parts store can check it for you. The generator light sometimes comes on in my bus when I first start it before the idle picks up a bit. If I tap the gas it'll go out and stay gone once the rpms increase. I believe both the generator and oil lights come on when I first start my bug and go right out but I'm not 100% on that.

[Cusser]

[waller]

Thanks for the replies- I was thinking battery as well. Totally caught me off guard yesterday but is operating as normal again today.

Battery is from previous owner- I have no idea on age. Maybe I should just replace it to be safe.

[1968BUGMAN]

It could also be the generator going out, but most likely the battery. I had a friend or had a similar problem with their bus, but it got to the point where they couldn't even jump it. I replaced their alternator for them and it runs great now, fixed the problems. I would recommend checking voltage/amperage of the generator when it is off. I also had a similar problem and it was my alternator.
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1968 Beetle Project | https://www.thesamba.com/vw/forum/viewtopic.php?t=...ae8942450a
Installing a Stereo Into a Classic VW | https://www.thesamba.com/vw/forum/viewtopic.php?p=9502179#9502179

[VW_Jimbo]

It could be dirty terminals at the battery. Take a look at them. Clean them up and see if that improves the situation. A little bit of corrosion will limit the charging of the battery and have the exact symptoms you have detailed.
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Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!

[waller]

Hi all,

Car died again, so I pulled out the multi meter and have the following readings:

- no key in ignition: 11.3 and declining slowly
- key in ACC position: 9.4 and declining to 8.9

Is this likely a battery issue?

Current battery is an Interstate 525 CCA. What do you recommend I replace it with? (78 FI Beetle)

[VW_Jimbo]

Battery or a big draw.

Remove the battery cables and recheck voltage. Does it climb back up?
_________________
Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!

[waller]

[1968BUGMAN]

You can use the amp setting on a multimeter to measure parasitic draw. With a bug it should really be at 0 if you don't have a radio with a memory circuit. 50 milliamps is generally acceptable. Also, did they mark the year/month for the battery?
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[waller]

OK so I have some updates but problem not solved.

-I replaced the battery and that's not the issue.
-Gen light not coming on
-With a boost, it starts right up but after two minutes of idling it dies.

Ideas?

[1968BUGMAN]

Check battery voltage, it should be about 14. If not it could be your generator. I recommend replacing it with an alternator if that is the issue. Make sure that it is 100% the issue before you buy stuff though, or you end up spending way more money than you need to.
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[waller]

It’s not the battery. It’s over 14.

Here’s a pic of some of the wires at the battery and in the engine compartment. What would you do?

EDIT: the first pic at the battery had electrical tape around this grouping of wires, one was not connected.

ALSO EDIT: Gen light seems to be coming on faintly if I leave the car for a while, like it's charging up.

[1968BUGMAN]

Okay, so I see you have a car audio fuse, I take it there is a stereo in the car. Make sure that this is not drawing power when the car is off. Also, sometimes the generator/alternator can produce proper volts but not amps, this was my problem.
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[waller]

I’m at a loss. Now, the battery is reading 6.3 with key on, 7.5 with the key off and 10.5 when I take it out of the car completely and test it.

Brand new battery.

What the heck?

[1968BUGMAN]

A large power draw somewhere. I say again use a multimeter set to amps at test the draw. Also, you probably have been draining it which is why it is so low. Put a trickle charger for a couple of hours before doing more testing so that you dont kill the new battery.
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[VW_Jimbo]

Hey man! Looks like you are chasing your tail a little bit. First stop and breathe.

Now, fix the connection at the battery cable(s). You have to start at the START. No going around it. Also, DO NOT use your meter as an amp draw test, there are better ways, that are just as accurate. The possibility of burning up a meter is fairly high, unless it has a fuse for protection.

Fix the connection.

Charge the battery.

Document voltage of battery after charging. Then install battery. Do not connect the cables yet. Go to Harbor Freight and pick up a cheap ($15) “clamp” style amp meter.

Reconnect you battery cables and set the clamp meter up on the positive cable.

Go to your fuse panel and start removing and reinstalling the fuses, one by one, checking the meter at each one. You are looking to see a drop in amps from one of those fuses. Hopefully finding the one which will allow less than .25amps to be drawn.

Good luck!
_________________
Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!

[1968BUGMAN]

Good advice about using an amp meter instead. I use a harbor freight multimeter that I got for free so I dont care if it blows up, my nice Klein once has a fuse, which I actually did blow at one point. A proper amp meter is better though. Also you can try redoing wiring like Jimbo said. I found that my car had really shotty wiring from the alt to the battery so I replaced it. While it didn't fix my problem it did help a bit, and it gives me some piece of mind that the wire wont fry.
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[waller]

[VW_Jimbo]

You are going to have to start by removing the wires one at a time from that battery connection. Then follow it to the next part. One of those wires has amps moving through it when the car should be off!

Couple of items come to mind right off the bat....A/C clutch trying to engage or is continually engaged, even though there is no belt. Might want to unplug the wiring if you have not already.

The ignition coil is an unprotected hot wire. Sometimes they burn out and cross into other wires. Maybe a previous owner had it burn our. They "fixed" it and it worked, but now it does not. I have tracked down this exact issue more times than I have fingers and toes in my house holds, including the pets!

Any of the relay driven devices have the possibility of the relay getting stuck in the closed position.

Just a few thoughts there. Do you have anything not working or working oddly?

If not, really what works is watching a meter, reading amps at the battery while disconnecting wires. The battery feeder to the light switch is an unfused battery hot wire.

Alternator field may be stuck.

CPU for fuel injection may be stuck. It works the fuel pump, too!

Maybe the ignition switch is leaking voltage to something.

My money is on the Alternator! Or even better, if there had been an alarm installed into the car at one time!!!!

The diagnostic port also has a battery hot in it that could become compromised. Seen that one, 1 time! That was a head scratcher of a day!
_________________
Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!