Starting Issues

[rubjonny]

cant use that method on a digi, you'll fudge the timing right up. use the digifant faq once you have replaced the blue temp sensort, get it from VW

edit: and the mk2 digi wont run with the AFM unplugged, thats normal

[danj3000]

Right well an update on things . . . I had a spare set of HT leads and rotor cap and arm so thought may as well replaced them. Initially it helped a little but not completely, but now i'm finding my car is starting fine from cold start, most bizarre. I shall be picking up the blue temp sensor later today from VW and just to be on the safe side, will go through your digi tuning guide Rubjonny.

Hopefully this will be the last i'll see of the cold start problems but I have a sneaking suspicion it could rear its head again but I shall see!

Thanks for all of your help guys, as I'm sure you know its far more stressful trying to sort your own personal cars problems out compared to someone elses!

[danj3000]

Another update . . . Replaced the blue temp sensor and that quickly became apparent that it wasn't the issue! never mind.
Its been getting progressively worse and a slight ticking noise could be heard by the engine. This lead me to think that one or two of the valves were not opening or shutting as they should and making one of the cylinders lose compression.
After a bit of faffing around I deduced that cylinder 4 was intermittently working, hence why the car was having issues starting.
I have a feeling that I may need to replace the tappets (they were done 25,000 miles ago)
The fuel injector for cylinder 4 was clogged up (I have used a fuel additive to help flush the injectors, I shall see how that goes)
I have just changed the oil, using an engine flush and also adding a hydraulic tappet additive with the new oil. As yet it does not seem to have cured the slight ticking and also there now appears to be water vapour coming from the exhaust, even when the engine is warm. So now i'm thinking I have a possible headgasket which is intermittently causing a loss of compression!!

All in all, not especially brilliant but I shall see how things go over the next few hundred miles but i'm thinking the best approach from here on in is to just buy a reconditioned head and obviously replace all the gaskets.

Has anyone got any pearls of wisdom that could help?! any is much appreciated 

[rubjonny]

water is a byproduct of combustion so i wouldnt be worrying yet, 1st step is a compression check!

[danj3000]

ok, well an update to things. Last night was the first time I drove the car any great distance and it purred away like a kitten, power had been restored and the tapping noise coming from the head had subsided. I thought happy days, and the new engine oil and additives etc had done the trick.

Now for the but! Car was playing silly buggers to start this morning and was running on cylinders 1-3 again for a few minutes, hence the trouble starting.
This is making me think that either the injector for the 4 cylinder is knackered or maybe the fuel injector rail could do with cleaning out. Or could it be that a couple of the tappets are knackered and making the valves stick open. The tappets were only replaced 25,000 miles ago, so I would be suprised if it were that.

Could it be something as straight forward as this?! Also I will take a proper compression test to see what that is telling me.

[rubjonny]

when was the last time you changed the cap, arm, leads and plugs?  could be damp buildup in one of the leads which clears after engine has warmed up.  coil might not be in the best of health either, and may as well try another tci unit as they're easy to change and plentiful. its the 7 pin thing bolted on top of the ecu bracket.

[danj3000]

I changed the cap, arm, leads and plugs last week. I'll have a look into the tci unit and coil. I'd be suprised if it is as simple as a build up of damp but if it can be a cheap fix I will be more than happy!

[danj3000]

Right, found out what the issue is and not all that great. The inlet valve was stuck half open on the 4th cylinder and has completed buggered up the valve seat, meaning the head is a gonna! Anyone who has a spare pb head around the south west is my friend!!