Golf Mk3 firing on 3 cylinders

Hi all,

Posting here again due to contiunued frustration!!

First some background. Having problem with Golf Mk3 '92 1.8 GL, 70K
miles. Engine (code ABS) is only firing on 3 cylinders, no. 4 is dead!
Compression test is ok, no notable difference between cylinders, have
new spark plugs, have tried switching HT leads round but still not
firing. Noticed slight oil leak from rocket cover gasket above cylinder
no. 4, is this a clue or just a coincidence???
Any tips on where to look next??? VW mechanic reckons these engines are
known for eating distributors but there doesn't seem to be a problem
with it sparking on no. 4, lead. Can see sparks flying across gap at
distributor cap with HT lead unplugged.
Have also tried holding throttle open to see if it's firing at speed
but it seems completely dead.
Any suggestions??? Knackered valve maybe??? I'm stumped :-!

Try the injector if it is injection, you have checked for 'spark' and
'compression', that only leaves 'fuel' - these engines are also known for
eating injectors if you get water in the fuel system.

If it is a carb, then try checking with WD40 spray around the inlet ports to
no.4 cylinder for any manifold leaks.

also you might try a new dizzy cap. just cos you get a spark doesn't mean it
is good enough, and you may not be able to see misfires visually, try
crypton tuning maybe.

Another thing to maybe try, if you have electronic ignition, the ignition
amplifier module may be faulty.

How do you know it's no.4 that is not firing, is there any gunk or rubbish
in the bore? - Try a Gunson ColourTune.

Andy

"Stevo" > wrote in message
oups.com...
> Hi all,
>
> Posting here again due to contiunued frustration!!
>
> First some background. Having problem with Golf Mk3 '92 1.8 GL, 70K
> miles. Engine (code ABS) is only firing on 3 cylinders, no. 4 is dead!
> Compression test is ok, no notable difference between cylinders, have
> new spark plugs, have tried switching HT leads round but still not
> firing. Noticed slight oil leak from rocket cover gasket above cylinder
> no. 4, is this a clue or just a coincidence???
> Any tips on where to look next??? VW mechanic reckons these engines are
> known for eating distributors but there doesn't seem to be a problem
> with it sparking on no. 4, lead. Can see sparks flying across gap at
> distributor cap with HT lead unplugged.
> Have also tried holding throttle open to see if it's firing at speed
> but it seems completely dead.
> Any suggestions??? Knackered valve maybe??? I'm stumped :-!
>

Hi Andy, thanks for reply,

This one's got single point (throttle body) fuel injection so I guess
the problem can't be injector related or there'd most likely also be
probs with other cylinders.
Have identified that the problem's with no. 4 by removing spark plugs
with engine running. There is a noticeable dip in RPM when each of
cylinders 1, 2 & 3 are disconnected but no change at all when cylinder
4 is unplugged.

vacuum leak possibly the hose to the brake booster. Or does your UK car
pull the vacuum for the brake booster from another area?
check all vacuum leads near that #4 cylinder

"Stevo" > wrote in message
ups.com...
> Hi Andy, thanks for reply,
>
> This one's got single point (throttle body) fuel injection so I guess
> the problem can't be injector related or there'd most likely also be
> probs with other cylinders.
> Have identified that the problem's with no. 4 by removing spark plugs
> with engine running. There is a noticeable dip in RPM when each of
> cylinders 1, 2 & 3 are disconnected but no change at all when cylinder
> 4 is unplugged.
>

Could be that the mixture is on the lean side. Try running without the o2
sensor (pull plug)

SFC

"Stevo" > schreef in bericht
oups.com...
> Hi all,
>
> Posting here again due to contiunued frustration!!
>
> First some background. Having problem with Golf Mk3 '92 1.8 GL, 70K
> miles. Engine (code ABS) is only firing on 3 cylinders, no. 4 is dead!
> Compression test is ok, no notable difference between cylinders, have
> new spark plugs, have tried switching HT leads round but still not
> firing. Noticed slight oil leak from rocket cover gasket above cylinder
> no. 4, is this a clue or just a coincidence???
> Any tips on where to look next??? VW mechanic reckons these engines are
> known for eating distributors but there doesn't seem to be a problem
> with it sparking on no. 4, lead. Can see sparks flying across gap at
> distributor cap with HT lead unplugged.
> Have also tried holding throttle open to see if it's firing at speed
> but it seems completely dead.
> Any suggestions??? Knackered valve maybe??? I'm stumped :-!
>

> Posting here again due to contiunued frustration!!
>
> First some background. Having problem with Golf Mk3 '92 1.8 GL, 70K
> miles. Engine (code ABS) is only firing on 3 cylinders, no. 4 is dead!
> Compression test is ok, no notable difference between cylinders, have
> new spark plugs, have tried switching HT leads round but still not
> firing. Noticed slight oil leak from rocket cover gasket above cylinder
> no. 4, is this a clue or just a coincidence???
> Any tips on where to look next??? VW mechanic reckons these engines are
> known for eating distributors but there doesn't seem to be a problem
> with it sparking on no. 4, lead. Can see sparks flying across gap at
> distributor cap with HT lead unplugged.
> Have also tried holding throttle open to see if it's firing at speed
> but it seems completely dead.
> Any suggestions??? Knackered valve maybe??? I'm stumped :-!

Could be a stuck valve or knackered camshaft but unlikely - suggest you take
the cam cover off & have a look at the cam & valve gear. Otherwise the
distributor cap/rotor arm would seem an option - you may be getting a spark
but maybe it isn't big enough - a hairline crack is all it takes to kill it.
Check for play in the main dizzy shaft - if its wobbling then that might
cause it to miss on one cylinder.

Check the plug gaps as well - if the gap is way to short/non existant that
would do it. Also try swapping the plugs around - you might have a bad one
with a damaged core.

HTH

I.