Electrical Gremlin

[VioletVW]

I’m having trouble with the bus. Problem is that now and again she will just die. When the ignition key is turned the lights dim and nothing happens. I have recently changed the ignition switch, the battery, the starter and added a hot start relay. When she does turn over she fires up without issue.

So, I am thinking about:
• Running a new wire from the ignition to the starter as I’ve no idea of condition of current wire. It may be 50 years old and shorting somewhere.
• Running a new wire from the fuse box to the coil as I have no idea about this wires condition either.
Any other suggestions are appreciated.

Finally, what gauge /amp wires should I replace the above with??

Cheers

Keri

[beetleben]

You said its a new battery, has that still got a charge or is it drained when you have the problem?

[VioletVW]

It sometimes happens when the bus is running, it simply cuts out and I have to pull over. May fire up on the next turn of the key, 1 min later or an hour. Seems completely random. That said I may drive 500 miles without a problem. It's driving me up the wall as there isn't a pattern: at a junction, on motorway, engine hot, engine cold.

[VioletVW]

In answer to your question, the battery is charged.

[Peter Good]

Keri,
From your description I seriously doubt it is the cables; much more likely a connector or connectors on the ends of the cables. May I suggest you check (with the battery disconnected) the push on blade connectors (assuming it is a post 1961 van) on the back of the fuse-box, and focus on the thick red cabled connectors especially, and make sure they are all a tight and secure fit.
Then check the state of the connectors onto the starter motor solenoid and focus on the several cables on the input M8 threaded stud terminal. Again make sure they are all absolutely clean and bright, and use a new and bright washer and nut if necessary.
Most electrical problems are generally much easier to resolve than they seem at first! Hope yours is too!
Peter Good

[VioletVW]

Cheers for that Pete,

I'll work my way around the bus this weekend to see If I can spot a dodgy connection. Fingers crossed it is as simple as that!

I'll keep you posted.

Keri

[ted698]

Make sure your battery connections are good - as this sounds like classic poor battery (high resistance) connectivity.
Are the battery clamps clean & bright shiny - and the wires going into them all good?
The short battery to earth cable on the body - where it attaches to the bus all good, shiny & bright.

[VioletVW]

Hi Ted,

I'll check on those connections too. Thinking about it the connection from the battery earth to the bus may be suspect...

Keri

[stu(pid)]

Could the ignition switch be faulty? Try moving the ignition key around while the engine is running, does it affect the engine?

[VioletVW]

It could be the ignition switch but this is a replacement one as the original broke. The problem was occurring with the previous switch too. I won't rule it out though.

[DJDUNKY]

Sounds like an earth strap is loose/broken

[VioletVW]

So...

I've cleaned up the contacts on the battery and earth strap and I'm having the same troubles. With that in mind I looked at the earth to the coil (from the fusebox?) and this particular cable has perished near the engine. I replaced a section in the engine bay but the problems continue. What I don't know is the condition of the cable from the engine to the fusebox?

As it happens a little while ago (I had forgotten I had done this) I ran a a 6 core cable from the front gauges (oil temp, rev clock, oil pressure) and I've only used 4 of the 6 cables. My plan is to use one of these cables as the coil earth from the fuse box to see if that eliminates the problem.

Its so frustrating as she will purr for a little while then start bogging, backfiring, generally running like a bag of s*&t then purr again or cut out and she may or may not restart as there might be nothing when the key turns...

Out of curiosity, where else would their be earth wires to check for corrosion?

Failing all of the above then I may just bite the bullet and replace the loom, 50 year old cable is bound to perish eventually.

[vwJim]

There's an earth strap between the gearbox and the chassis.

I'm curious what you mean by earth to coil from the fuse board?

[VioletVW]

Sorry Jim, am I right in thinking the coil negative wire runs to the fusebox? It's can black wire that runs through the engine bulkhead and goes into the main loom. I assume it goes to the fusebox...

[stu(pid)]

Is the "coil negative" wire on the same connector on the coil as the wires to the choke and fuel cut-off on the carb, or the same connector as the green wire to the distributor (or black wire if you have electronic ignition)?