The bosch fuel pump is, by default, set to operate at a raised idle. There were several designs to control this, apparently, the waxstat being one of them. However, I am only familiar with the electrovalve type which utilises a vacuum to pull on a cable, negating the increased idle when the engine is warm.
Locate the fast idle lever at the rear of the fuel pump, cambelt end. With the engine running - taking all sensible precautions - try to push the lever using a screwdriver or similar against the return spring force and you should notice the revs drop. If so, then your controlling device has failed.
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CitroJim
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The waxstat was the earlier arrangement fitted to non-EGR and fully mechanical pump versions of the engine. '95 models could have either the waxstat or electrovalve depending on the pump fitted. If you have the semi-electronic pump and ECU, you'll more than likely have the electrovalve system.
The waxtat itself is a large alloy cylinder that screws into the thermostat housing with a bowden cable existing from it going to the pump fast-idle lever. It works on the same principle as a themostat where the wax expands with heat and this movement is transmitted through a bowden cable.
After a few years they stop working and in fact, very few work at all these days. They are cheap enough to obtain but are a pain to replace because you need to drain the coolant and access is not particularly wonderful. Many, including me on my old TD, live with duff waxstats
The electrovale system is under ECU control and is dependant on the coolant temperature as read by the green sensor on the thermostat housing and a functioning vacuum pump, to be found on the end of the engine, driven by the camshaft.
The waxtat itself is a large alloy cylinder that screws into the thermostat housing with a bowden cable existing from it going to the pump fast-idle lever. It works on the same principle as a themostat where the wax expands with heat and this movement is transmitted through a bowden cable.
After a few years they stop working and in fact, very few work at all these days. They are cheap enough to obtain but are a pain to replace because you need to drain the coolant and access is not particularly wonderful. Many, including me on my old TD, live with duff waxstats
The electrovale system is under ECU control and is dependant on the coolant temperature as read by the green sensor on the thermostat housing and a functioning vacuum pump, to be found on the end of the engine, driven by the camshaft.
Jim
Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...