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Model specific boards => Golf mk3 => Topic started by: jbh39 on 19 January 2011, 20:45

Title: Surely someone must know?
Post by: jbh39 on 19 January 2011, 20:45
Mk 3 GTI, running fine, parked up for the night......next day, nothing. starter motor doing what it should, fuel getting to engine, sparks sparking. Why No Firing up?? I considered a timing belt slip....? think I may have sorted that, BUT,  still no go.  Please does anyone have any ideas???

How can an engine with spark and fuel not be doing its thing? I even tried fast start. nothing..............
Title: Re: Surely someone must know?
Post by: snifferdog on 19 January 2011, 20:48
The engine is turning over as if it is trying to start?
Title: Re: Surely someone must know?
Post by: jbh39 on 19 January 2011, 20:49
engine turning but no fire.
Title: Re: Surely someone must know?
Post by: snifferdog on 19 January 2011, 20:52
Hmmm, not really sure then mate? Maybe the coil pack?
Title: Re: Surely someone must know?
Post by: jbh39 on 19 January 2011, 20:55
Thought maybe if it was the timing belt slip, then surely would have heard something? If it had damaged the valves then......the other thing I thought was perhaps a sensor? Where though, could end up creating more of a problem. Ever heard of this?
Title: Re: Surely someone must know?
Post by: snifferdog on 19 January 2011, 20:58
I gotta admit, Ive not had this problem before, Im sure there will be someone who can help alot more than me soon enough.

Title: Re: Surely someone must know?
Post by: jbh39 on 19 January 2011, 20:59
Cheers comrade. Be safe.
Title: Re: Surely someone must know?
Post by: dazzawest1987 on 19 January 2011, 21:06
Well to me if it's got fuel got a spark, assuming the fuel pressure your getting is ok, it may not be getting both at the correct times so maybe crank or cam sensor dunno if your car has one or both, poss as said timing slipped unlikely in my opinion or I,be had cars with blocked breathers and cats try starting it without oil cap on.
Use the search and have a look through other threads aswell you may come across the answer there
Title: Re: Surely someone must know?
Post by: Christo77 on 19 January 2011, 21:16
Need to think about that it was ok one day and not the next.. have you done anything prior, hit something, knocked something, fiddled with something..remember the cold has returned also, did you wash it the night before..has damp crept in somewhere that hasn't been attended to in some years service wise
This assuming you have absolutely no sign of it firing while trying to start it..
Also, is your battery failing.. i know with mine it wont start if the turn over rate is down a bit.
Title: Re: Surely someone must know?
Post by: jbh39 on 19 January 2011, 21:29
Well, Like  I say, sparks fine, fuel is getting in, been on jump leads coz of running battery down since the problem. starter motor doing its job. Just before xmas I treated it to new fuel pump, filter, tyres, and the bloody front suspension and full tracking.......was running beautifully................And now its dead. Thought it may be an air issue? ive tried it with the throttle open, is there a sensor in there that may have gone? doesnt seem to have much to do with the possibility of the cam belt slipping, (this is what AA men reckon). I just dont know, may have to sell it as a non starter.
Title: Re: Surely someone must know?
Post by: Deano2711 on 19 January 2011, 21:38
Try getting it hooked up to a Vag Com cable or fault code reader. Vag Com available off E.Bay for around a tenner. Faulty sensors etc will come up with a fault code in most cases. May help in the long run.
Title: Re: Surely someone must know?
Post by: harlemex on 19 January 2011, 21:40
try disconnecting your maf sensor plug.
Title: Re: Surely someone must know?
Post by: Christo77 on 19 January 2011, 21:44
Remember the cambelt is toothed, would have to be worryingly slack to be able to slip..or the tensioner has failed.
But, you can easilly check that and check that the timing marks line up, if that's all ok then well..it's guessing from here really.

As said already by others the coil would have been my first shout also, as you seem to think that's alright then you just gotta get back to basics and check the obvious things first.
From the items you mentioned already there's other things like fuel/ecu relays, MAF sensor, Hall sender..have you checked breather and vaccum lines..
Title: Re: Surely someone must know?
Post by: james42 on 19 January 2011, 22:31
i`ve been looking at jbh`s car today. found the timing belt slightly loose. removed no1 spark and determined tdc with proding device, marks on cam pulley did not align with the mark on the head.it was about 5 teeth out. re set cam but no difference.good spark and petrol arriving at chamber. spark will ignite mixture with spark plug held at open spark plug hole. apparently no valve crunching noises were heard initially and there are none now. i`m thinking compression test next,if good compression that means the valves are seating nicely, right? tried with mass air disconnected.tried to remove throttle potentiometer but it was keen to stay where it was. i`m keen not to create a secondary issue by breaking it. code reader sounds a sensible move. other than the valves is there anything that could be damaged by the belt jumping?
Title: Re: Surely someone must know?
Post by: Christo77 on 19 January 2011, 23:18
If the cambelt has managed to jump out of it's toothing on the pulleys then that's quite a concern and who knows how far round it's actually travelled!
If a belt has been subjected to even very slight damage or just purely suspect about it's age/condition then it should be replaced period.
If the thing has jumped round then the toothing may well be damaged and must be discarded!
Also you'll need to check the pulleys for integrity including the tensioner and that ideally in this case should be replaced too..

All that asside, the first thing though is a check on the cylinder head/valves for damage, ie with your compression test i guess..
Title: Re: Surely someone must know?
Post by: Wayne on 19 January 2011, 23:33
Sounds like it has lost compression
Title: Re: Surely someone must know?
Post by: Dubbyboy on 20 January 2011, 09:34
This may sound completely numpty like, but I had a similar experience the other morning.
Parked up the night before, not a hint of an issue, following morning not even a hint it would fire up.
Tried allsorts, then tried something my in-law does when he starts his car.
Put my foot on the throttle half way down (I know it's injection and shouldn't need to) and I got a splutter from the engine.
Stopped then planted my throttle to the floor (with all the turning over I knew there was oil pressure by now) and the thing burst into life.
Ran a bit ropey at first then cleared itself, touch wood hasn't happened since.

It's at least worth a try, won't cost anything.
Title: Re: Surely someone must know?
Post by: jbh39 on 20 January 2011, 14:47
Thought I had better conclude this.....turns out when I turned the engine off, the timing belt HAD slipped. Very lucky it hadnt messed the valves up! Managed to sort it out.....................phew. :grin:
Title: Re: Surely someone must know?
Post by: Christo77 on 20 January 2011, 16:00
Well nice one..indeed your lucky!  You haven't re used the old belt i hope..
Title: Re: Surely someone must know?
Post by: thai-wronghorse on 20 January 2011, 16:45
What made you suspect a slipped cambelt?
Title: Re: Surely someone must know?
Post by: dazzawest1987 on 20 January 2011, 18:37
Well nice one..indeed your lucky!  You haven't re used the old belt i hope..
+1 or the tensioner
Title: Re: Surely someone must know?
Post by: polo6n222 on 25 January 2011, 22:01
is the oil light flashing when your trying to start it