Ok here's the latest update:

As way of managing the process I have replaced the fuel filter...(just a side note when I took out the old one the fuel that came out of it was quite dirty, almost rusty looking)

Car is running quite smooth except under load after warm up on low rpm's there's a bit of "engine ping/dieseling noise" greatly reduced over the last week as I am running fuel line cleaner etc...

Got into the car Friday after the 12 mile drive to my daughters car started/ drove about 100 feet sputtering/ and then died...turns out the fuel pump fuse was popped again AFTER it started (or perhaps AS it started didn't drive far at all)

Replaced fuse car started right up.

Yesterday after replacing fuel filter I drove it about 30 minutes came home and parked it, went out to start it this morning right off the bat the car spun but no igniting of fuel, popped trunk sure enough fuel pump fuse is blown again.

At this point I am ready to replace the fuel pump (Have one here already)

Two questions before I do...is it possible the fuel pump relay is bad? (I pulled it today and it is quite warm but I am not sure what to look for or if I can actually test it, I do have a 12volt bench top variable power supply and plenty of Ohmeters so i could supply power and test it but I'm not sure which leads would go where and there is no schematic that i know of)

Second question...the primary fuel pump is showing a Ohm resistance of about 81 ohms, the new pump is only 31 ohms (this is obviously the resistance of the coil) lower resistance is better, but I notice there are two pumps and from my reading the main pump is on the right hand side the other pump is simply the tank transfer pump, is it possible it might be pulling down the fuse by current increase or should I just replace the primary fuel pump?

I never have run out of fuel and the gauge/level seems fine no issues that I can tell there.

 

Replaced fuel pump...just for reference I measured the resistance of the old one and out of the car on the bench the coil measures 1.6 Ohms...which is frankly barely anything at all...the new one is 31 Ohms...

My thinking is the fuel pump was probably going out, once it spun up it probably was fine, but the initial start up was pulling way to many amps (although this seems counter intuitive at the moment) high resistance means more current since we only have so many volts to work with...I'm going to put the meter on the new one and see what the voltage drop is...

 

Which fuse?

#17 in the trunk? This is the one that actually powers the pump, via relay #7 and the RECM.

#4 in the primary junction box? This is the one that controls relay #7 for the fuel pump.



My experience with relay temperatures here, specifically post #4:


https://www.jaguarforums.com/forum/s...-r-s-c-187819/





Wiring diagrams here, scroll down to section 3.4:

http://www.jagrepair.com/images/Auto...x2022001en.pdf

The easiest way to test a relay is to swap it with a known-good relay from another position. I think the AC compressor uses the same type relay (#8 in the front power box), but doublecheck to be sure.

You can also test the relay by connecting an ohmmeter between contacts 3 and 5. With the relay unpowered, there should be no continuity. Apply a ground to contact 2 and 12V to contact 1. The relay should energize and contacts 3 and 5 should now show good continuity.

 

Actually, it's the other way around. More resistance slows down the current.

I wouldn't worry too much about the specific ohm readings you measured, unless you have a specification that the ohm reading should be within a certain range. The big question is how does the new one run?

The low resistance you measured on the old one would agree with higher current draw and the blown fuse. Motors are kinds weird when measuring resistance, though. You get all this backfeed from the spinning armature and everything changes once it's in motion, so a simple resistance reading doesn't necessarily mean all that much.

If you really want to get slick, spring the $14 for one of these amperage testers:

https://www.harborfreight.com/30-amp...ter-67724.html

It plugs into the fuse block and reads the current flowing through the circuit. It's a super easy way to measure amperage draw.

 

So far no issues with the new pump, it seems to draw a little less voltage on start up, biggest pita was removing the fuel line clips, the red and white one...what a pain!

Fuel pump $10.00 on ebay...exact fit.

Took the old pump to my bench 12 volt power supply to try it out, it spun once then died, never to spin again...so just in time I think.

 

Yes I should have clarified, I meant if there is a lot of resistance then it requires more current, thats why I said it seemed counter-intuitive to me, the lower resistance of the old pump SHOULD have required less current (lower amps) and would not be popping fuses...but I am a novice on this stuff and the Ohm reading on a coil is not super indicative of much other than its not open/shorted...I really only tested it to make sure it was not shorted out.

But reading your post again it now makes sense, the lower resistance means more current flowing which is why the fuse kept popping...to much flow.

 

After reading the thread definitely was the pump. Looks like you caught it just in time! Nice work!!

 

2000 s type 4.0 v8