1991 (H) Escort 1.6 CVH Carb Idle Problem

I am having trouble with my idle on the above vehicle. It has distributorless ignition and a throttle sensor on the carb. The idle drops when the load is taken off the engine, i.e. slowing down at a roundabout, this sometimes causes the car to cut out. According to the Haynes manual, the idle is set by shorting across pin 1 & 2 of the throttle sensor, then earthing out pin 5 of the diagnostic socket. However, I have no wire in pin

Now on EFI models there is an idle speed control valve which normally gets gunged up and requires cleaning out, however, I cannot find anything like this on the carb model. Anyone able to shed any light on what to look out for. The car runs fine and starts ok, has new plugs and air filter.

Regards

John

Is this an auto?

Anyway, in either case you should have a throttle kicker which slows the throttle's movement back to idle speed. This needs checking that it is receiving vacuum from the PVS and is able to hold the tickover to ~1000rpm when operating, and then letting idle drop back to 850-900 rpm. I find that a "tighter" setting on the kicker works better- prise out the plug on the top and screw in the allen screw abit so it hold the rpm up and decays abit slower.

Obviously you need to check the induction system carefully for vacuum leaks first and set up the carb to give a nice steady smooth idle at the correct CO and speed- check the slam panel. Do this by first checking the TPS is giving about 0.7v at idle speed. I personnally leave it connected when setting the carb. If you disconnect it and the ecu reverts to base timing you invariably have to reset the tickover again after cos it jumps up too high.

Make sure the engine is fully warming up too and that the auto choke is coming fully off. You're wasting your time until these are right. I would also use carb cleaner and blast off all the oily crap that acculates on the top of the carb from the PCV system, and also pull out the idle and main jets and ensure they are clean and free from oily goo also.

Hope this helps to begin with.

Tim..