This may be a dumb question but is the cooling fan supposed to turn on when the engine is just started and cold? I noticed the car has a very rich fuel mixture when idling but it smoothens out as it is warm. After checking everything else was good I came to the conclusion that it has to do with either the temp sensor being bad or components related to it as the fan always is on. The coolant temp sensor for the injectors was good but I replaced it anyway just to play it safe. The wiring looks to be okay but is there anything else I may be missing? Im not sure if these fans are always supposed to run or not

Without information regarding the car model and year, you will not get a correct answer, Is this a 6 cylinder or a V12? If a V12, the electric fan runs as an integral part of the cooling system whenever the climate control is switched on.

EDIT- Its a 1987 Jaguar XJ6 with the 4.2 6 cylinder

Haha forgot the most important part of it all! Its a 87 xj6 with the 4.2 6 cylinder

Unless modified by a previous owner the fan should run only when the coolant temp hits xxx-degrees (94şC as I recall).

What is your temp gauge reading? Ideally it should be 82şC to 88şC . This is well past the range where cold running enrichment would occur.

Here's some reading on rich mixture and cooling fans:

https://www.jag-lovers.org/xjlovers/xjfaq/efirich.html

https://www.jag-lovers.org/xjlovers/...nchecklist.htm

Cheers
DD

Those are the exact sources I have been reffering to funny enough! So I ohmed out the old sensor and it was good but replaced it anyway just in case. The car runs very rich at idle but once it gets up to the 90 degrees celsius it runs alot smoother and doesnt seem to run as rich. However that being said itll hesitate and is hard to drive until it reaches that point. I wasnt sure if there was a relay to check or something else. The fan is on as soon as the car started

Okay update, with the thermal switch unplugged, and the relay, the fan still runs. Maybe a short to power?

The wiring has been modified...or oddly shorted to power as you say. Or the fan is being powered via the #11 fuse rather than via the relay. If the latter I would suspect that one of the two blocking diodes has failed. Pull the #11 fuse and see what happens

Cheers
DD

Also consider this:

https://www.jag-lovers.org/xjlovers/xjfaq/efiover.htm

Cheers
DD

pull the wires plug connected to the red relay mounted on the radiator frame and see if the auxiliary fan still runs.
in my experience it is always the red relay stuck.
Option 2:
pull fuse no. 5 at the small fuse box next to coolant fill tank, counting right to left, number 5 is the auxiliary fan fuse.

The auxillary fan has been long siezed, I was told this should not affect the regular fan.

I havent been able to locate the fuse? Where should I be looking for it? Thank you for all your help so far

Wait.

Have you been talking about the "regular fan" all along?

It is belt driven. It spins whenever the engine is running.

We thought you were talking about the aux (electric) fan.

Cheers
DD

Just what I thought….of course the white (now yellowed, no doubt) engine fan runs, as Doug says, whenever the engine is running.