Disconnect and then reconnect the main engine wiring harness,just
above the gearbox.My mk 3 used to do something similiar and it was just a bad connection.

 

Sounds like a dizzy problem! My mk3 used to do the same and i replaced the dizzy and it's still going strong!

 

Dare I day it that aside from checking connections etc sounds like you should bring to vw main dealer to diagnose?

My MK3 GTi (jeez thats a long time ago!) crapped out but it was ECU that went and it behaved like you described apart from the fact it cut out at about 80mph on the M50 late one night - not what you want to happen. It was initially intermittent but then when it eventually went the issue seemed to be temperature related as when it cooled down a bit I was able to limp on until it heated up again. They said it was an issue with the PCB (printed circuit board). While it was intermittent I spent hours trying this that the other connection wise looking for a bad connection or corroded one - kneedle in haystack issue.

Pain in ass on car you just got but it can happen anytime.

 

QUOTE(duffgti @ Nov 7 2006, 09:48 AM) [snapback]38699[/snapback]
Disconnect and then reconnect the main engine wiring harness,just
above the gearbox.My mk 3 used to do something similiar and it was just a bad connection.


Hmmm... Haven't taken it off yet (and not too sure I want to either as I don't wanna upset the timing) but it's quite possible... Was checking it there and the plug I pulled out doesn't seem to be sparking when it turns over... Yeah, there's always the bring it to the dealer business alright, but I'd like to have exhausted all the silly little things before I bring it in and pay someone €200 to tell me a connector fell off or something...

QUOTE(duffgti @ Nov 7 2006, 09:48 AM) [snapback]38699[/snapback]
Disconnect and then reconnect the main engine wiring harness,just
above the gearbox.My mk 3 used to do something similiar and it was just a bad connection.


And try as I might, I can't get that bloody connector to come off! It twists off, bayonet-style, yeah? Doesn't seem to want to budge at all

 

Could be your alternator. I had something similar with my MK2. I think it was a weak alternator. Sometimes it was fine, but sometimes with lights etc on it woud die. The battery was ok to be able to start the car again...most times. Rev counter woud drop to 0 then the lights came on - oil and temp.

 

QUOTE(DaveQ @ Nov 7 2006, 07:12 PM) [snapback]38789[/snapback]
Could be your alternator. I had something similar with my MK2. I think it was a weak alternator. Sometimes it was fine, but sometimes with lights etc on it woud die. The battery was ok to be able to start the car again...most times. Rev counter woud drop to 0 then the lights came on - oil and temp.


Funny, the first time it happened I did find a loose connection to the alternator, but in the grand scheme of things didn't seem to be the problem...

George and myself were looking at it last night, and I still have to check a couple of things, but at the moment it's looking like the ECU

It's only giving roughly a 2V signal to the camshaft position sensor - which should be 12V - though that could be a short somewhere on the loom or other sensors running off the ignition on signal. Will try the other sensors tonight and see, hopefully a dead sensor is all it is...

 

*bump*

Well, it's all fixed now, thank Christ! Turned out to be the crankshaft position sensor, but what a balls of a job!! To even reach the sensor the front engine mount and the oil filter had to come out, and that meant taking out the starter motor bolts (which hadn't been touched in 10 years and were pretty well stuck). Then, once I got to it, the bloody sensor came apart in my hand and left the stump in the side of the engine block. Not nice!! After about 2 hours of trying to drill it to get a grip on it and prise it out (not easy cos it's a ceramic material) I enlisted Geo's help to drop the sump off it and push the sensor out from the inside the crank case. Eventually put it all back together and drove her home last night... Bastard of a job!!

 

And all that hardship was after a 2 hour diagnosis session in the dark last week, not to mention all the phonecalls and trips to the dealer to get the correct sensor as the first one they got was wrong.

It fought us all the way but we didn't let the bastard win

 

Thankfully it's sorted but that's a bitch of a job to have to do! What time did you get finished last night?

 

Well, George headed off at 10 I think... I took about 30 mins out then (Having been in work for about 14 hours at that stage was getting a bit much), and it was around 11:30 when she was finished and driving... Afraid of my life driving it home though, waiting for a clunk as something I forgot to tighten falls off, but it was all ok!

Need to find a new set of bolts for my ECU though

it's rattling around under the cowling at the moment...