The car seems to have a mind of its own. It will run PERFECT one trip. Then on the way home, black clouds of smoke, lack of power, EXTREEMLY poor fuel economy. I am baffled.

When it chooses to run well, idle is a bit high at just over 1000 RPM. When the ôotherö effect is in place and the engine is warm will not idle above 500 RPM IF at all!

Here is what I have done thus far. Pulled the throttle body, cleaned it, re-installed and set the close gap. Removed and cleaned the air block, re-installed making sure that the idle adjustment screw moves freely. Replaced the extra air valve with a good unit out of a parts car. ( are they supposed to open all the way or just about half way?) I have checked the temp switches in the water body and found all but one seems to work per the manual that I have. (on CD Factory Service Manual version 7.0 Jan. 2004)

The one switch that does not seem to change state at high or low temp is located at the rear of the water body. Two terminals and is marked Elmwood 3000, EAC 3762, L 45 C, 3385.

What does this switch do, and what are the indications of its failure?

Any assistance would be helpful.

Thanks
Dennis
86\' XJ6

Submitted by dougi@shaw.ca on Thu, 05/05/2005 - 23:44

Dennis,

I'm thinking there might be some overfueling going on. What do the spark plugs look like after one of these episodes? Have you checked the fuel pressure? Is the cold start injector working properly?

Doug Ingram
Victoria BC Canada
1987 Series III XJ6 VDP

Submitted by dougdwyer@adel… on Thu, 05/05/2005 - 15:44

Dennis,

That switch serves various functions, the primary of which is to operate the AIR pump diverter valve. Normally the switch would be closed on a cold engine and open on a warm one. On my car it has been stuck "open" for ages....I keep forgetting to replace it...but my engine runs fine. If it was stuck closed some complications may result (keyword: MAY) as the switch ties in with the air switching module and has a bearing on open/closed loop operation. Remove the wires and jumper them together and see if anything changes; I'm guessing nothing will.

I'll give some thought to your problem and postback when I have some more time, but I wouldn't focus too much on that particular switch.

Cheers

Doug Dwyer
Longview Washington USA
1987 XJ6 Ser III
1988 XJS V12 Coupe

Submitted by reisdp@hotmail.com on Thu, 05/05/2005 - 14:51

Forgot.....also ran through several jugs of Chevron Techron injector cleaner. Thought that maybe I had some bad stuff in the injectors from running on regular gas for awhile.

Dennis
86\' XJ6