Club 80-90 Forums

Hi, I am sure people must have asked for advice on this previously but I must ask again....

I have a well serviced and sound running 1.9 petrol T25 (55k) - but recently it has been cutting out, behaving like it is running out of fuel when there is plenty left in the tank - I have been lucky the few times it has happened and been able to pull over to a safe position on the road, and after a good few minutes of mild panic and wondering if I should call the AA - it has re-started.

My only thoughts came back to a thread I read a while ago (should have bookmarked it!) regarding sediment in the fuel tank - once engine off and sediment settling again, allowing engine to run and all ok to press on.

Since the last time of this happening the carb was rebuilt (nothing untoward or fault was found) new fuel filters fitted - all appeared to be ok, until it happened again, quite unnerving but again able to start after a few minutes of engine off.

Is this something that other T25 owners have experienced, and been able to rectify? I also had a very strong smell of fuel when I filled it to the top for a long trip to Norfolk, which went once the out on the road and fuel was used.

Any advice would be gratefully received, summer 'might' be here soon and I need to get my confidence back in the motor!

Many thanks

Yes..it's not a nice feeling when you are unable to rely on a vehicle, being unsure of whether you are going to get to your destination...

Of course you have mentioned one possibility and that the flat low design and age of these vehicles leads to gunge build up on top of the tank leading to holes appearing in the top and metal pipework.
The heavy smell of petrol when full is also an indication that you have a leak and that it needs investigating. The common issues are the numerous short lengths of rubber hose (eight?) that connect the tank to the expansion bottles under the front wheel arches. These pipes perish and split and it isn't uncommon to see fuel pouring out underneath when filling at the petrol station (not a good thing to be happening)

I think you are at that stage where it might be prudent to drop the tank in order to have a closer look, change the tank if needed or at least change all the hoses.
If the tank is corroded, lots of crap will have found it's way into the tank and that could indeed be the problem.

However.....don't rule out other possible causes:
When this fault occurs, is the resultantant misfire/holding back/stalling.....subtle as in surging or does the engine literally drop one or two cylinders?
I'm just trying to decide whether this could be an ignition fault which is more on/off than a fuel problem.
This could be plugs or plug leads breaking down, distributor cap perhaps (remove the metal plug cap shields as they are a known cause of break down)
Faulty ignition switch (quite common for the switch to start playing up, can usually be checked by moving the key side to side when the fault occurs)
Does it appear to be over fuelling when it happens? (choke mechanism faults where the choke butterfly is not being held open when hot)
Does it only happen when the engine is hot? (breaking down of electronic components ie: Hall effect sender/Coil/ignition module)
Are you having any associated issues with lights going dull (battery not charging) broken earth leads/positive battery connections.
Have you got the original petrol filler cap (incorrect cap causing the tank to vacuum)

Martin

Hi Martin,

thank you for your very informative response... I'll try my best to be clear on your questions...

"When this fault occurs, is the resultantant misfire/holding back/stalling.....subtle as in surging or does the engine literally drop one or two cylinders?"
... not sure if it's misfiring, it does not want to idil sometimes when warm - the engine cutting out is more just an instant lack of power, no throttle response (like it is running out of fuel), just 'spluttering' can feel like all is going to be ok, and then engine stopping, no idil on restart either.

"This could be plugs or plug leads breaking down, distributor cap perhaps (remove the metal plug cap shields as they are a known cause of break down)"
... it did have a new distributor cap recently too.

"Does it only happen when the engine is hot? (breaking down of electronic components ie: Hall effect sender/Coil/ignition module)"
Engine has always been warm when it has happened, not especially hot, just normal-ish running temp.

"Are you having any associated issues with lights going dull (battery not charging) broken earth leads/positive battery connections."
.. no all ok on this front (hope I don't speak too soon!)

Have you got the original petrol filler cap (incorrect cap causing the tank to vacuum)
... standard as far as I know, uses the VW key.

Planning to have tank removed end of this week as per your suggestion - that appears to be the most logical path, and then go from there, hopefully we will get to the source of the problem by a simple elimination process.

Very grateful for your previous response.

Cheers, Paul

Can we assume the fuel filter is new?
Fuel delivery from the pump is good?
That the choke is working correctly?
And finaly there are no vacuum pipes amiss or air leaking into the inlet tracts

We have had exactly the same issues on long journeys Paul, usually after about 2 hours of driving. We rest her for 10 mins then off she goes like nothing ever happened.

Much like you we have changed filters, checked ECU, fuel lines etc but nothing out of the ordinary yet.

I will follow this post with interest. Good luck!

kevetherev - thanks for your input too.

It has 2 new fuel filters - another was added just before then carb just to be sure to catch any sediment that might get past the first after the tank.
I think fuel delivery is all ok - would appear to be fine and makes no strange noises - assuming it would strain if not working correctly?
Choke comes off within a few minutes of a cold start.
Regarding the pipes amiss or leaking, I will make sure that this is taken note of when investigating fuel tank - and replace accordingly.

Danmetallic - I will make sure that I post the outcome - which I hope will help you too.

Cheers, Paul

T25PM wrote: It has 2 new fuel filters - another was added just before then carb just to be sure to catch any sediment that might get past the first after the tank.
I think fuel delivery is all ok - would appear to be fine and makes no strange noises - assuming it would strain if not working correctly?
Choke comes off within a few minutes of a cold start.
Regarding the pipes amiss or leaking, I will make sure that this is taken note of when investigating fuel tank - and replace accordingly.

Danmetallic - I will make sure that I post the outcome - which I hope will help you too.

Cheers, Paul

Paul
the second filter was never fitted by VW, it really is overkill and could cause delivery issues.
there is already a filter inside the carb, can we assume this too has been eliminated from investigation?
By pipes I mean vacuum pipes, if air leaks into the inlet side will cause stalling when the engine warms up.
you think fuel delivery is ok, it must be eliminated from your investigation, as this is a fuel delivery problem.
checking is easy enough.

one other thing, does your coil get hot?