Yet another cutting out problem

Just driving along normally and the engine cuts with no warning - if you turn the ignition key it instantly restarts.

This can happen every few minutes and often is accompanied by a backfire on restart - presumably unburnt fuel igniting.

Because of the backfire I've assumed that it is not a fuel supply issue but an ignition one.

It starts, idles and accelerates fine - well as well as a 1600SP can in the latter case.

All the ignition electrics etc. are new, as the bus had to be virtually rebuilt.

For insurance purposes we had to have an immobiliser fitted but it ran fine initially after fitting, about 600 miles ago, and now seems to be getting worse.

I was wondering whether it was a faulty ignition lock/switch - even though they're brand new VW Classic parts.

This may be not be relevant but the indicator warning lights have both failed recently, although the indicators still work.

Any ideas?

Thanks

It does sound electrical, I'm afraid all I can suggest is you go through things one at a time. Could it be a loose connection somewhere, maybe at the fusebox, or battery terminals?

Thanks Mike.

We did have some problems of the same type when we had some of those 'quick-release' battery clamps, which were too quick to release, usually over bumps.

They've since been replaced with normal battery clamps.

It looks like it's going to be a slow and methodical process of elimination, starting with the connections as you say .

It's a pain in the **** as it's one of these problems that happen and then disappear.

Once again, thanks

Do all the electrics fail when the engine stops? Could be the main feed connector that is loose, the thick red wire into a multi plug by the ignition switch.
Mine was loose and did similar to yours, stopped dead but with no power to the switched circuits.


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Yep - they do.

Will check connector.

Thanks for the help

Rich

So far have found a loose bare wire under the dash but haven't checked for any improvement yet as have managed to flatten the battery after flooding the engine! Yes - I am an idiot.

Here's an update.

The engine now cuts out instantly if the key is released but runs fine if the key is held against the spring.

When it cuts there is a beep from the immobiliser. I don't know whether this is the immobiliser cutting the engine or beeping as a result of the engine cutting.

Sounds ominously like the immobiliser, immobilising you..


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chad said:

Here's an update.

The engine now cuts out instantly if the key is released but runs fine if the key is held against the spring.

When it cuts there is a beep from the immobiliser. I don't know whether this is the immobiliser cutting the engine or beeping as a result of the engine cutting.

Click to expand...

does this not mean the ignition switch is faulty? :msn4:

I have heard of this happening on some old switches and also on new repop ones. That is one reason I put a hard start relay in the circuit on mine : to minimise the cranking required at the ignition switch.

To be honest I don't know - it's got new, supposedly good quality, parts and a hard start relay and used to start pretty quickly.

I'll let you know what is is/was when it's finally sorted.

Thanks for all the advice everybody.

Well it turned out, as has been suggested, to be the electrical switch that 'mates' to the ignition switch.

I think this must have been damaged during the installation of the immobiliser, which also resulted in the loose wires, and then it gradually failed.

Thanks for all the help everyone.

Glad you got it sorted out.

I have an immobiliser as well and touch wood haven't had any problems with it, although I have had loads of issues with the new radio the same people fitted! You sometimes think 'why did I bother!' :roll:

I know what you mean - the problem was I couldn't get insured unless I had an immobiliser fitted