Van stalls when out of gear even when warm - ? cause

[julieD]

Hello all,

I'd be grateful for any advice as to what might be causing this problem. My van stalls when out of gear, either at 50mph in 5th gear, or when coming to a stop in 2nd gear... 
I have a T25 from 1990, water-cooled 1.9L camper.
It runs well otherwise and recently MOTd with fuel and oil filter change. 

I'm having an odd issue that the mechanic couldn't figure out- even when the engine is warm, it'll easily stall when I come out of gear. This can happen even when I'm in 5th gear and want to take it out of gear to save fuel, which is problematic when at 50mph ...
As I come to a stop I'll gradually reduce gears, and then when hoping to stop in 2nd gear and I remove to neutral, it'll stall.
I've managed to avoid this by reving the engine when in neutral, which seems to prevent a stall and I can then stop in neutral and the engine holds in idle.

So it feels like it's an engine inlet problem or something ? as reving the engine in ideal seems to help.
Could it be electrical ? (my radio no longer works and seems to coincide in timing). 

Otherwise again engine is sound and runs well. It'll take the van a little while to first warm up on start and I need to rev for 30sec before it'll hold idle. 

Would be grateful for any pointers thanks
Julie 

[Aidan]

So it passed MOT, and emissions were correct ?
Or was it a 'friendly' mot and not properly tested - the info should be with your MOT certificate in the form of a print out showing the CO and HC measurements If the CO and HC readings are correct then the carb is set up ok and the air and fuel and spark are in spec.

Coasting is not advised (it's not strictly illegal but highway code does strongly advise against doing it), fuel savings are minimal but more importantly you do not have full control of the vehicle, especially if the engine is stalling, as that is a distraction, and you are either relying totally on the brakes (with no servo assistance whilst the engine isn't running) and also relying on the engine restarting as you turn the ignition to start or slip the clutch to use your momentum to restart the engine, you are also wearing the release bearing unnecessarily if you are holding the clutch pedal down and loading the crankshaft spigot bearing as well, if the engine is stalled. It's a habit to get out of imho, like resting foot on clutch pedal or resting hand on gearstick. 

First guesses would be a fuel supply or fuel quality issue, maybe water in fuel or a minor blockage in the supply, an air leak in the fuel lines or the brake servo hose on the manifold, or a less than ideal fuel pump function

[silverbullet]

Don't forget an air leak in the vacuum system: suck test the distributor capsule for a failed diaphragm (and also the pull down unit on carb) and all vacuum hoses inc. the servo pipe connection off the inlet manifold and the small lines to the valve on the filter box.
If the inlet has been off for head work then fit new gaskets and install them with a little Dirko or Reinzosil both sides as the manifold can warp with age, affecting the effectiveness of the seal at the clamped faces.

[TwinTurbo]

Check the idle shutoff valve click when you unplug/plug it. It's located on the carburettor facing the back of the vehicle , the cylindrical item sort of in the middle of this



If it's not clicking with the ignition on then it's power feed may be dead.

After that apart from the sugestions above, I would inspect the Auto Choke and make sure it's being fully released, if it's not then the engine will be overfuelig to the extent it dies.

Rob

[TwinTurbo]

@julie any progress?

[julieD]

Dear all,

Thanks a lot for your suggestions, I didn't have time or tools to have a look into this myself so took it back to a mechanic that knows the van and asked for them to look into this with your pointers.

It sounds like it might have been a problem with the vaccum pipes to the carburettor. I'll ask for details tomorrow and will report back.

really appreciate the help and suggestions!
Julie