Jaguar Repair: 1984 Jaguar jx6 idles too high, jaguar jx6, coolant temp

Question
Howard,
Thanks for the info you are a great resource. I noticed my xj6 idles at about 1300RPM. There is a lot of black smoke when it starts and it does seem to fade once the car has been running. What is the proper idle RPM and any suggestions on bring the idle and exhaust issue up to speed.

Answer
Hi Curtis,
That is most likely more than one issue. The idle speed after warm-up is controlled by the idle screw but the black smoke (excess fuel) can be a hundred things. If you intend to keep this car you need a service manual.
Your fuel pressure could be too high, the coolant temp sensor could be sending false info to the ECU, any one of the injectors could be leaking. The cold start valve could be stuck open or held open electrically, Your pressure regulator could have a bad diaphragm. To mention a few.

Howard