Club 80-90 Forums

I noticed that my '88 2.1(dj?) Caravelle is idling at around 1000 to 1050rpm so with my trusty pocket manual I went on an exploration to places never seen before....the engine. By comparing the drawings in the manual to my engine I've found that the idle stabilisation unit has been removed (I wondered what that thing was rattling around in the glovebox!) with the plugs joined together. The overrun cut-off switch and the full throttle enrichment switch have also been removed with the two wires still there, and there's also a yellow plug with a white/green wire floating around not connected to anything over by where the voltage stabilisation unit should be. The van appears to run OK with the exception of a dead spot found when you try to accelerate after covering the throttle and maintaining a steady speed (60ish on the motorway for example). A full tank of fuel will return about 250miles of combined driving, which I'm not sure if that's good or bad. The van is currently fitted with a diesel 'box after the previous owner struggled to find a replacement when the original failed.
My question is: should I refit the stabilisation unit and source the other switches and fit them or should I go for the 'if it ain't broke don't fix it' approach and leave it as it is, and just reduce the idle using the screw by the throttle set up?
I've spent the last 10-or-so years working and spending losts of money on my air cooleds and hanging around the cool and beautiful people of the splitscreen fraternity, but it's come to the point (I'm nearly forty!) that I should come back down to earth and mix with the working class out there and drive a proper camper. So far it's been great fun to drive and I wish that I had bought one years ago so until I get to grips with all this 'modern' technology I'll be plaguing you all with loads of questions. Cheers. Ross.

It will be a DJ if there is no lambda sensor on the exhaust header before the silencer.

These fuel injection systems are generally very reliable, but can be thrown completely off course by a simple fault that is very difficult to identify.

The engine was obviously designed with all the parts working. The idle stabilisation unit is there to boost the revs when there is high demand from the alternator or the power steering. I would not worry too much about that. The throttle position switch tells the idle stabilisation unit when the engine should be in idle mode, which has it's own special map in the ecu. It also enrichens the mixture on full throttle, and cuts fuelling on the overun. I have actually seen no sign off either of these things happening on my DJ which I have fitted with a lambda probe to monitor the mixture. Re fitting these items may not make any difference to the normal running of the engine, and for correct running the throttle switch needs careful setting. If you are happy with the way the engine runs normally I would leave alone.

The dead spot I would suspect the vacuum advance on the throttle. When you hit the gas pedal the vacuum will drop causing the timing to become retarded( ) sounds like this might not be happening.

With the gradual increase in the tick over I would suspect the temp sensor for the ecu. get one from Baxter. or.... (as your idle stabilisation is missing this might not make such a big difference)

The throttle bodies wear in there old age and you begin to run out of adjustment as the butterfly gets wobble on it's shaft allowing more air through than expected.

250 on a tank is not too shabby.

Many thanks 'Simon, I think I'll leave well alone. The fast idle doesn't bother me too much so if I can't reduce it using the idle screw then I'll just leave it as it is. I might try running it with the idle stabalisation unit fitted to see if there's any difference but as the van's not fitted with power steering then I suspect it won't do much. Thanks again.