1992 MK2 GTII turns off (engine and electrics) whilst drving

[WillGT21985]

Hi all,

I'll start with a little bit of back story. For about 12 months I've had a sporadic fault on my K reg MK2 GTII. From October last year onwards it began turning off and back on again whilst driving. By this I mean that the engine and the electrics turn off. This usually happens for a second or two and then everything comes back on, usually without me having to touch the key.

In July this year it turned off whilst driving and wouldn't restart, again both the engine and the electrics completely off. I had it recovered, fitted an new ignition switch (old one burnt out), and was able to drive it as normal for around 90 miles before the sporadic fault began reoccuring. That's where I'm currently at.

It turned off and on multiple times during a journey to work across a town centre with busy roundabouts so I took it straight to my usual garage. They've had it for over a week and it's not played up during their runs out in it. Their first thought was that perhaps the new ignition switch was faulty as these are now all after-market pieces and not VW genuine, but nothing happened on them so they've not looked at that. I did ask them to check earth connections, ground connections, radio wiring etc for shorts and the like but again nothing suspicious was found.

Has this happened to anyone? Any idea what I should look into next?

Thanks!

[GT_II]

The only thought I have is that if the old ignition switch was burnt out, I would expect some damage to wiring connectors and possibly the wiring. If so, it is possible there are bad connections, leading to unreliability and eventually burnout

[james butler]

check the x relief relay as this powers a lot of things
also check the battery clamps are tight and ESPECIALLY the fuse box wire connected to the positive pole is tight and not loose as ive had that be loose on my car and would cause it to cut out randomly
other than that your looking at earths and tracing wires from ignition and fusebox for damage and burnt wiring as unfortunately if the ignition switch is bad then more may be bad too

[WillGT21985]

Thanks for this. Where exactly do I locate the fuse box wire you mention? Please bear in mind that I'm not familiar with this area of the car, cheers.

[james butler]

if original there is a chunky red wire going from the positive battery pole to the fuse box
check that wire is tight and if you have a multimeter it would be a good idea to check voltage drops in and around the fuse box (ie 12.6v on the battery should equal 12.6 and close to it in and around the fusebox etc)
might be worth someone local giving it a once over with you to help narrow the fault down

[WillGT21985]

Hello again, after a month of healthy driving the fault has re-occured. This time I took it to a different mechanic and he seems to think it's a dashboard issue, with either the PCB or the processor. Maybe a damaged piece of solder etc.

Now, I've had this fault for a year, and it's cost me a reasonable amount of money, and a lot of time and anxiety whilst driving. So, I'm asking you lot for advice...do I proceed and locate an auto-electrician who can fault find behind the dash, or is it time to say goodbye and sell it as a project?

I'm imagining that dashboard fault finding is a timely and expensive process as I do not have the ability to do this myself.

[GT_II]

I'm not an expert, but I would be very surprised if the fault was anything to do with electronics or pcbs. That's not to say it's going to be easy to trace the fault. Ideally you need to find an auto electrician familiar with Mk2 Scirocco/Golf electrics, rather than one specialising in modern ECU-based electrical systems