Took the car out today and it seems to have developed an 'interesting' problem. I drove for about 20 minutes, no problem at all. Got to where I was going, stopped for about 2 minutes, started up, and drove for a very short distance, no more than 2 minutes. Stopped the car, did what I had to do and drove for about another 25-30 minutes. So far so good. Got back in the car after about an hour, drove for another half an hour or so and stopped outside a mates (who has just bought himself a mk2), he came out straight away to tell me I could park on his driveway and the car wouldn't restart. It was turning over but wouldn't fire up. So, 15 minutes later, try again and hey presto! the bloody thing starts first turn of the key. Another 20 minutes passes and it's time to go, and would you Adam and Eve it, it won't start again. 10 minutes passes and away we go. So, I finally get home 20 minutes later and as I am about to reverse up on to my driveway and I stall (not my fault, honestly) but thankfully it starts right up. I park up, turn the ignition off and think to myself, "will it start right up?", answer is, no it bloody well will not! Any pointers gladly received as I had a list of jobs to do already over the coming weeks without fannying around trying to solve this one. Cheers guys.
I'm leaning towards it being spark plug, purely because I can hear the fuel pump priming when I turn the igntion on and there are no other running issues. If it was a fuelling issue would it be more likely to be all or nothing? I'll whip the plugs out tomorrow morning - damn these dark afternoons - and have a good look.
Its not an ABF , is it? They seem to like a 'non start', from my experience. LOL Jon Fuel or sparks. Tin of easy start and a spare plug would be the kit I would carry to try and diagnose
Digis are really simple. Check basic stuff like the ecu plug connection ,the ecu ground, the airflow meter plug connection , wires on the coil and dizzy.
mine had a similar odd fault turned out fuel filter was partially blocked. one day drove home as per usual, then a few hours later no start. Next day, fires straight up and drove fine up the road and parked up in town. Come out the shop and nothing, would fire on easy start so changed filter and problem solved! another odd one was all of a sudden it decided that every day without fail it would not start on first crank of key. 2nd crank, fired straight up. no matter how long or short you held it on the starter, nada 1st crank, fire 2nd crank. Would run faultlessly once started, for as long as you wanted. would fire up just fine at the end of the day and get me home no problem. then next morning, same deal. That turned out to be the blue temp sensor for the ecu bizarrely...
Have you checked blue ecu temp sensor my digi wouldn't start after a forty minute run and after a ten minutes switched off, it would start fine from cold ie leaving overnight then it started playing up starting then I changed blue temp sensor and fine
Sorry for the lack of updates guys, it's been hectic. So, finally managed to have a look at the car today and this is where I'm at. Replaced the blue temp sensor and thought that had sorted the problem. The car started each and every time for about half a dozen goes, then we were back to square one. Checked the earth to the ecu, that looked good. ECU itself looked fine as did the air flow meter plug and wiring on the dizzy and coil. I did notice that if I removed relay #32 and put it straight back in the car fired straight up. I couldn't get one locally today so cleaned it up - although it looked fine - and sprayed a bit of contact cleaner in the relay board but it didn't make any difference. I've attached a pic showing the relay and fuse box - #32 was the third position, immediately to the right of #72. Could this be the issue or just coincidence? Might it also be a symptom of something wrong elsewhere? I'm not sure why the pictures aren't posting. I can see them when I "edit post" but otherwise nada, nothing, zero, zilch. https://imgur.com/I3K65df
Cheers Tristan. I keep getting search results saying a #109 is the new replacement for a #32 - do you know if this is correct as I can't seem to find #32 anywhere.
Lol - just tried my local VW dealership. After being on the phone for 20 minutes, "That relay (32 & 109) was discontinued in 2009. Try VW Heritage."
It also comes up as the ECU relay for VR6 as far as I have found, I can't seem to find a definitive answer.
What I have just found is that there is a bonding lead running from the coil to the right side of the rocker cover (or just below), but that bonding lead hasn't been secured to the coil, it is held in by a bolt but no washer or nut, so isn't actually making contact with very much or anything. Replaced the bolt and tightened everything up but it has made no difference.
Ok chaps, this is doing my swede in now. The car started first time this morning. Let it run for a minute, turned it off, turned they key and again it started fine. Left it for a minute, turned it off and fired up straightaway. Left it 5 minutes to get nice and warm, turned if off and started right up. This time I took the car out for 20-25 mins up and down the a14 and no problems. Returned home turned the car off, and she started up again. Feeling confident that everything was grand and I was unlikely to be stranded on a petrol station forecourt I left the car for 20 minutes while I had a celebratory cuppa and now the bloody thing won't start again. Just tried the car again now after leaving it the best part of 10 hours and fired up first turn of the key. Immediately turned it off, turned the key back on again and not a sausage. I did notice though that there was a very strong smell of fuel.
My Digi stinks of fuel after a cold start , so much so I thought it had a leak! Yet runs perfect and passes MOT easily . Did you pull back the rubber boots on the afm and dizzy plugs, to check for broken wires? The spark amp and even Ecu too. The ecu comes apart easily too if you wanted to check it for corrosion.
I have done mate, yeah. The wiring was in a pretty shocking state when i got the car so had a friend who does aircraft avionics to go over alot of the loom. I have checked splices, crimps, re-wiring etc for signs of being compromised on all the things you have listed, but I haven't taken the ecu apart. So far though I have changed the ecu relay (#109 went straight in) and the blue temp sensor, checked the spark plugs and they are all fine and sparking like a good 'un. Cleaned up and checked the bonding leads that I can see, I have had a look under the square-ish plastic cover over the ecu and what's underneath doesn't look in the best condition though - so that will be the next port of call I think.
Right, I think I'm making progress. I have dropped out the dash surround around the fusebox to get better access. I have noticed that although the fuel pump can be heard priming, when I hold touch relay #32/109 (brand new) it doesn't always "click", even though the pump can be heard. When it doesn't click, the car won't start, when I can feel it click the car will start. I can't understand though why the fuel pump will prime even though the relay doesn't necessarily click?
