Club 80-90 Forums

1987 Caravelle 1900 . DG Auto....... Every time I slow down to about 10 mph the engine cuts out. Starts immediately on restarting.( Happens when engine is warm/hot.. Never when cold) The problem only started recently, last 2 weeks or so and is slowly getting worse. Not purchased fuel from any different garage (always use same when driving local) I have had a quick look to check that nothing has come disconnected or dropped off, can find nothing obvious. So any ideas or suggestions welcome.

Sounds like the Idle stabilisation valve isn't compensating and allowing the engine to stall.
Isn't there some sort of control relay behind one of the rear lights that's known to give problems.....never having had the problem myself, seem to remember someone talking about this.

Martin

throttle body switch sends the signal to the ecu to tell the idle stabiliser system 'you have control', so I'd check that that is switching correctly first, then the check the rest of the idle system, probably the idle stabiliser/air bypass valve is stuck, sticking or has failed or has poor electrical connection, if not then the control unit behind the off side lights or the secondary control unit next to the TCi unit

Hi Guys Thanks for replys and suggestions. Very informative. Problem is its all goblegook to me Can we have it in not Teck speak please

I had a similar problem a few years ago,
I had fitted new plugs, and the van (2.1 DJ) started occasionally stalling.
Eventually discovered that one of the new spark plugs was faulty.
The van ran perfectly at all other speeds.

T

sounds similar to what I had a couple of years ago,it was crap in the carb,I removed the cone shaped filter in the carb and cleaned that out,blew out the jet with a compressor and blew out the fuel that was in the carb,no more problems

air leak?

https://club8090.co.uk/wiki/Fu ... _Air_leaks

quote from above article - 'worse when engine hot, choke off; worse in cold weather sometimes....'

Again, thanks for suggestions. Checked for air leaks, with sprays of various amounts of flammability. Not yet removed carb to strip and check. This will be done when the weather gets a bit warmer. (Its freeeezing out side at the moment) Although I have checked obvious things like plugs. H.T. leads, Distributor Cap, I get the feeling the problem is electrical. But as my knowledge on engines is of the old school, pre electronic ignition and computerised any thing on motors, I am lost at the moment with this problem.

Auto choke ??

kingprawn, thanks, don't think so. Engine runs perfectly when driving, no black smoke or rough running. Just stalls as I slow down for junctions or lights Etc.

As was said earlier in the post....many of the VW/Audi engine range around that era, used an air by-pass sytem (idle stabilisation valve) to increase/decrease idle spead in order to compensate for 'engine load' caused by a number of factors.

Automatic transmission drag (when in drive the torque convertor/fluid creates drag and tends to pull down engine idle revs).
Alternator charging load (turning on lights/heater blowers etc) also loads the engine bringing the idle speed down which can result in stalling.
Lean burn stalling (typically when hot and after sustained speed) the engine has a natural tendancy to stall for a few seconds on overun whilst slowing.
Cold start (which requires a richer mixture and a higher idle to prevent stalling)
Power steering drag (if fitted loads the engine whilst manouvring) tries to stall the engine.

As you can see from the above...there are many circumstances under which the engine NEEDS ASSISTANCE to remain running and prevent stalling. The idle stabilisation valve is the device that assists, adding air into the inlet manifold to increase the engines revs each time system detects a possible situation when the engine is struggling to idle.

The 'round torpedo shaped device' works by moving a valve internally to allow additional air to by-pass the throttle butterfly to increase the engines speed. As we said earlier, this device may not be working correctly, meaning any of the ABOVE natural accurances could cause the engine to stall.

Martin

California Dreamin...Thanks, I can almost understand all of that I have considered most of the listed items, Auto Fluid drag..no difference long or short drive ie fluid warm or hot. Not driven at night for weeks. No high speed driving. No power steering. So it may be idle stabilisation valve. But where do I find this 'round torpedo shaped device'

How did you get on with this problem. My 1.9 water cooled 5-speed petrol van has been doing the same after long sustained speed drives (60mph). Runs great when cold and on short journeys.
After these long journeys it stalls at every junction/ traffic light which is a pain. Starts fine though.
Interested to hear if you fixed yours or if anyone else can suggest anything.
Thank you.
Mark

Choke presumably helping maintain idle mixture. Once choke goes off, mixture too weak at low throttle openings and it dies. Check for air leaks somewhere. Base of carb, hose to dizzy, anywhere that additional air could be making its way into inlet side. Either that or its been tuned with the engine not fully warm and the choke still partially on

Sunny afternoon here in Stirling so just off to investigate now. Read through some of Wiki last night too. I'll update on progress.
Thanks for reply.