Alternator issues

An alchemy of sparks, copper wire and earth

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Paradise City
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Alternator issues

Post by Paradise City »

I had a very disappointing evening last Friday. Instead of rolling down to Folkestone to get the Eurotunnel to Belgium for half term, we ended up getting towed back home having got only 25 miles out of London!

Anyway, I'm just posting this to ask some advice to see if my theory of what went wrong is plausible.

I changed the alternator drive belt a few weeks ago and as I was putting the new belt on I felt a wire that I had to move out of the way to slip the belt onto the alternator pulley. The van started no problem and we went to GoOutdoors to get a top up gas cannister and did the 12 miles round trip with no issues. The next day we drove approx 4 miles to a park and on the way home the van was really struggling on hills and cut out a few times giving me the dash low battery light.

I put it down to the van having been off the road for a while, charged the battery and had a couple of short runs with no further problems, until last Friday evening that is.

After getting home and doing a bit of reading and researching prices for a new alternator and discussing selling the van with my wife (again) I thought I'd have a look as I thought that I may not have tensioned the drive belt properly.

I was getting about 12.4V on the battery which dropped to around 12.2V when the van was running.

So I found this blue lead going into the alternator which I believe is the exciter wire

https://drive.google.com/open?id=0B-Srz ... jRza0NDNkE

As you can see there is exposed copper. Could it be that the exciter wire was grounding and stopping the alternator from functioning so the van was just running from the battery? I think it would explain the gradual loss of performance as the battery ran down but I'm open to suggestions.
I re-insulated the wire and tied it up away from harm's way and things seem to be OK again and I'm getting 14V when running

https://drive.google.com/open?id=0B-Srz ... GxQWEpVVWM



While I was fiddling about with the alternator I found this wire as well, it wasn't connected to anything...

https://drive.google.com/open?id=0B-Srz ... 2xLYkFYWjA

but the other end was connected to the earth behind the passenger side rear light cluster

https://drive.google.com/open?id=0B-Srz ... y1PV2txMG8

Any ideas what it would've originally been connected too?



And while you're here :D , I noticed this cable had become disconnected, it looks like it should be connected to a spring loaded arm on the fan housing. Anybody know what it's function is?

https://drive.google.com/open?id=0B-Srz ... 3NtXzU2TFE

https://drive.google.com/open?id=0B-Srz ... S1sWnJ3V3M


Many thanks in advance!!


***E D I T sorry for all the links, couldn't post the images within the body of the post!


2.0l Petrol T25 air cooled
1981 Air-cooled 2.0l petrol

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bigherb
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Re: Alternator issues

Post by bigherb »

Yes the blue wire grounding could have stopped the alternator charging.
Cut out the damaged section to the connector and put in a new connector.
You would have been running off the battery only until it drained down and not enough enough power to work the ignition and the auto chokes would have come back on.
The other wire is not original.
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California Dreamin
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Re: Alternator issues

Post by California Dreamin »

Agree...repair the blue wire: cut out the exposed section, join another piece of wire (solder preferably) with new spade etc.
The other wire is an earth but not original, as Big Herb says, I'm guessing is an addition (not a bad thing) to the engine? however, not up to the job as main earth (between engine and chassis) and there will be/should be, a much heavier braided earth on the gearbox (commonly replaced as they do corroded to dust).
Not sure about the other stuff, maybe something to do with heat exchange flaps (air cooled) heating in cab.

Martin
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Re: Alternator issues

Post by Paradise City »

Thanks guys, that's reassuring!
1981 Air-cooled 2.0l petrol

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Re: Alternator issues

Post by Paradise City »

So I fixed the alternator wire and the alternator seems to be working OK, 14.1V across battery terminal when running, dropping to 13.4V when headlights are on.

Took it for a few laps around the block and am unfortunately having the same issues. Interestingly, it cut out at exactly the same point on the hill on each lap and after I pulled in to reverse into the driveway, it cut out and wouldn't start at all (that's the first time it wouldn't start again). I poured a little fuel into each carburettor and it started first time and ran for about 30 seconds before dying again.

After a lot of pushing, shoving, carburettor fuel filling and cursing I managed to get it safely back onto the driveway.

So I reckon the alternator wire was a red (blue) herring and it's actually a fuel starvation problem.

It's a new fuel filter but the van had been off road for over a year before getting MOT'd in September.

It seems to be a common problem judging by the number of threads on here. Going to check the filter, lines, pump and pushrod length when I get back from holidays.

Anything else I should be looking at?

Could anybody point me in the direction of a tutorial on how to clean the jets on a Solex H32/34 carb? Can you do it without removing them from the engine?

Cheers
1981 Air-cooled 2.0l petrol

multisi
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Re: Alternator issues

Post by multisi »

Lots of info , diagrams and photos of the carbs in the green Haynes workshop manual.
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Paradise City
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Re: Alternator issues

Post by Paradise City »

Thanks, will check that out.
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bigherb
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Re: Alternator issues

Post by bigherb »

I would concentrate on the fuel supply. Twin carbs would unlikely both block up at the same time, and the engine will still run on one carb.
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Paradise City
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Re: Alternator issues

Post by Paradise City »

Yeah. Pump, push-rod and filter will be the first things I check. I really don't want to have to start fiddling with the carbs if I don't have to.

Thanks.
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Mr Bean
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Re: Alternator issues

Post by Mr Bean »

By coincidence I had a problem this weekend on a family visit to my folk in Dorset. about 100 miles into my journey I switched on my side lights and a little later my dipped headlights. As the headlights came on I noticed the battery warning light glimmer but not brightly. I switched back to the sidelights and it more or less went out but I felt it was still glowing compared to the green light next to it. By the time I got to my destination I had to use the headlights again and the light came on again I guess at about 75% brightness. As we were to stay over a couple of nights I decided against using the AA as I guessed they would either recover me straight away or some other arrangement which might not suit my plans. I would have to pay for an alternator anyhow. Luckily enough my middle grandson instructs motor mechanics and when I spoke to him he offered to come over and have a look at it. To my surprise the alternator apparently worked perfectly when he came next morning - Saturday - giving 14V with the light coming on fully when ignition initially switched on and going out completely when mote running. However:
When my clearly more thorough grandson got involved he got me to gradually switch stuff on while he ran the engine at about 2,000 RPM with a multimeter connected. Sure enough as I switched on items beginning with the Fridge and headlights the indicated voltage petered away down to 11V and beyond. I guess that with a hot engine in a hot engine bay this was the conditions under which my alternator was failing. Anyway the nice person at GSF in poole found a 90A alternator in stock. Happy days :D
The moral: Volts is good start but watts come with current.
CS
E D I T Yes the meter was connected at the alternator.
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bigbadbob76
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Re: Alternator issues

Post by bigbadbob76 »

If the problem appears "at the same point on the hill" I'd be suspecting crap in the fuel tank or filter.
Just my 2p worth but might be worth a try.
Hope you find it.
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Re: Alternator issues

Post by Mr Bean »

An old trick if suspected a problem in the ignition system is to temporarily close up the gaps on the plugs to 15- 20 though. Likewise you may be able cobble up a completely separate fuel supply just to eliminate that problem. I once used an outboard motor tank and rubber squeeze primer pump to finish a trip towing my boat. Retarded ignition can cause holding back or symptoms as you describe.
CS
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Re: Alternator issues

Post by Paradise City »

Thanks guys. Still haven't gotten around to doing anything yet, life gets in the way! Great info and suggestions.
1981 Air-cooled 2.0l petrol

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Re: Alternator issues

Post by Paradise City »

Thread resurrection

Hopefully going to have some time to get under the van this weekend.

I had a quick look just to see where the fuel pump was and how awkward it is to get to. It looks like there's an oil leak coming from around the pump. Do you reckon this could cause the fuel pump to malfunction or is it a sign of a failing pump? (I haven't tested fuel lines yet but I will do on Saturday).

Think I'll probably end up replacing pump, push rod and gaskets.

https://photos.app.goo.gl/2oBMmXP2n2dvwcCR2
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Re: Alternator issues

Post by Paradise City »

Got the fuel pump off, push rod was 5 mm short.
Decided to install electric fuel pump and replace all the fuel lines while I was at it. (Thanks to advice on threads re: electric fuel pump).
Van running well now, just back from half term trip to Holland and Belgium fully loaded with wife, 2 kids and 4 bikes.

Only problem I had was night before we were due to set off the van wouldn't start, no fuel in carbs as it had been sitting for a couple of weeks without being turned over. Squirted a few ml of petrol in the carbs and it started first time and hasn't given any bother since.

Will think about installing a primer button to get the fuel pump and lines primed before starting as at the moment the pump only runs when the alternator is running.
1981 Air-cooled 2.0l petrol

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