Camper runs for a bit then stalls

[maverickMechanic]

Hi,

A good friend of mine has a 1983 Devon Camper, that has been in a VW garage since November with the same or similar problem. They bought in the summer to go camping and as a daily runner for light use.

Date of registration: 01/03/1982
CC: 1970
Fuel: Petrol
Twin carburettors.

The initial problems was: the engine would start well when cold, but would sometimes cut-out on idle when warm. It was thought to be set to run too richly and when they were in Devon a mechanic adjusted it. For a couple of weeks it idled well and ran a bit better.

Then the vehicle began to stall regularly. They first noticed the it when driving back from London. Initially it lost power when they tried to accelerate beyond 50mph. As they carried along the situation got worse. It wouldn't run beyond 40mph, then 30mph, then 20mph, then stalled and they had to run off onto the hard shoulder. By letting the engine cool down for 15 minutes or so, it would start again and they would limp along for a bit until having to stop again.

The garage believe it is a fuel feed issue. It will sometimes start and when it does it idles well, sounds good and runs smoothly for a short while, before cutting-out. Starting is then difficult and stalls if you pump the accelerator or try and move off uphill.

The vehicle was returned regularly to try and fix the problem, the stages of work done by the garage (that I can remember) are:
replaced the original petrol tank, which was rusted at the top
replaced the original mechanical pump with the 1st electric one
flushed the tank and system, in case of debris from old tank
cleaned the carburetors
replaced the 1st replacement tank
replaced the 1st electric pump with the 2nd electric pump
replaced the 2nd replacement tank with the 3rd petrol tank (from a different supplier)
replaced the 2nd electric pump with the 3rd electric pump
fitted an additional (and more powerful) electric pump
tried swapping the alternator with one from a working engine

So we are on the 4th tank and 4/5 pump.

I am thinking perhaps the problem is with the carbs, I remember many years ago having a strange issue with the float and valve in the carb that meant it would run for a but then needed a rest. Any pointers would be great as I want to go to the garage and try and advise the mechanic so at least they can get their camper back. After that I'll post the name of the garage with a "never-take-your-van-there" warning, but first things first lets try and get it fix.

Please help.

Regards

Peter

[Ralf85]

A VW franchise garage in the UK is not the place to take a camper. They won't have a clue. You need to get it to a specialist garage that understands these old vans to solve the problem. Somebody on the forum must be able to suggest somebody! Trucker?

[300CE]

Hi Peter, have they tried 'feeling' the coil after it stalls? I had kind of the same symptoms on my van - was stuck in traffic one day and then it struggled to pull away before stalling & then it wouldn't start. I then had to let it cool down & it started fine before doing the same again once warm.

The coil I had was a new, but a crappy make and was extremely hot to touch where it was breaking down internally. I replaced it with the 30 year old bosch one that i'd kept (and cleaned up all the connections) & it's been fine ever since.

[Bubble Meister]

So the fuels been investigated but what about the ignition side? What engine and carbs are fitted?

If a clear fuel filter was placed before each carb then the fuel flow can be seen.

It sounds like slow degradation on the motorway, that would hint towards the electrical side breaking down. Have the leads and plugs been replaced?

[kevtherev]

This needs a methodical approach.

Timing is the first thing that must be eliminated...is it correct
fuel, is it a good supply to to the carbs, are the carbs in good order, do they operate properly.
Sparks, the ignition side (coil, leads, spark control, plugs, cap, arm..)
Air, are there any leaks on the induction side, weak mixture will cause over heating and the engine will fade out.

[akroblade954]

+ 3 for the coil. I had the same problem. As everything fuel wise has been changed (several times!!) except the carbs, I would guess ignition as it is unlikely that both of the carbs is failing identically at the same time.

As this is an air cooled 2L, it will have electronic ignition and need a particular coil. The ones listed on GSF etc are wrong and won't last as they over heat and breakdown. Many are listed as suitable for T25, but simply won't work properly with the electronic ignition on that bus. This has been discussed many many times by experts on these buses all over the world...

Get them to test the resistance of the coil. Values should be:

Primary resistance [between terminals 1 & 15 - the 2 wire connections each side of the HT] - .52Ω to .76Ω
Secondary resistance [between terminals 1 & 4 - HT to either wire connectors] - 2.4kΩ to 3.5kΩ

If it is out of range, it will need replacing. 5 minute job!!

Its a VW part number VW No 211 905 115 B, or get one from Brickwerks (5% discount for Club 80-90 members ) https://www.brickwerks.co.uk/index.php/ ... y-din.html

[maverickMechanic]

Thanks all for the replies. I will help them check the coil and electrics. I like the idea of the fuel filters to check for flow as well.

We are in Brighton East Sussex anyone suggest a good T25 Aircooled specialist here?

I will update shortly.

Peter