Yes, the Schrader valve can be used with a mechanical pressure gauge to read fuel pressure at the fuel rail.

 

If you push the valve core, does any fuel escape under pressure?

 

Yes. When I pushed down on the tab in the center fuel immediately came out. I bought a fuel gauge but it didn’t come with the correct size fittings. I was going to try and use my ac gauge but once the fuel started coming out I stopped.

 

Still working on figuring out what’s going on with my car. This is what the cars on board diagnostics is saying.

 

Have you been clearing all codes every time you check?
We really need to see if things are changing/improving.

The low battery voltage is the most worrisome because as you know a low battery will set all kinds of strange and weird codes.
So we always suggest getting the battery squared away as the first step.
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I just swapped batteries out, one I just put in was showing 12.8 after charge. Once connected to terminals it battery read 12.43, and with key on run position battery read 12.20. I still need to check on fuel pressure and fuel pump sensors and relays…

 

I did clear codes the day before the no start occurred. The car did run and start no problems twice earlier in the day prior to the no start. Since then no codes have come up on either scanner that i own just the P1000 or whatever code means self testing... I have not tried starting the car in about two weeks. Im waiting for some help so that i can do a full fuel system check and battery test/alternator test.

 

So I’m getting nothing from fuel pump when turning the car to run position (while listening to pump from rear seat), also no fuel pressure at Schrader valve. Did check fuses and relays, all seem to be working so I’m ready to order the fuel pump and change it out. Anybody know the part number for the 03 4.2???

 

The fuel pump is VIN-specific. Here is a listing from SNG Barratt, one of the forum sponsors:

https://www.sngbarratt.com/English/#...ds=%5B26361%5D

When ordering the fuel pump, be sure to check fitment against the vehicle VIN.

 

Ok so I changed the fuel pump with success and I can now hear it turning on, however I’m still getting very little pressure on fuel gauge just barely above zero. When I was attaching the fuel gauge to schrader valve there was fuel present just barely dripping out. I already have a new fuel filter and tools necessary to swap that out next. Any suggestions before I get that done???

 

Making some progress! You may not think so, but you are.

It would be highly unlikely for the fuel filter to be severely clogged, bad enough to practically stop the flow of fuel. Still won’t hurt to try it, as it is part of routine maintenance.

When you have the filter out, I’d suggest rigging up a hose on the line from the tank. Run the hose into a bucket. See if you’re getting any fuel reaching the filter.

If still nothing, I remember a thread from the last year or two about a lack of fuel pressure. I think the guy ended up finding a line had come loose at the pump module, inside the tank. The pump was running, but was dumping fuel right back into the tank. Does that ring a bell to anybody?

 

Here’s one possibility. See post #5. Not the one I had in mind, but still relevant:


https://www.jaguarforums.com/forum/s...-start-250263/

 

I had to do a search for the non return valve and according to what I found I’m sure that part was connected. I’m going to install a fuel filter tomorrow, while it’s off I’m going to try and take a reading with fuel gauge if that doesn’t work I’ll at least run the hose and see if I’m getting fuel output from sender/fuel pump.

 

Found it! See post #19:

https://www.jaguarforums.com/forum/s...-issue-236934/

 

I’m going to check that hose is reconnected before I get to the fuel filter. Thanks for the info. Ill let you know how it goes.

 

So I checked the connections at fuel pump everything looks good. Haven’t yet changed the fuel filter. Still not sure what’s going on with fuel system, going to pick a part later today to possibly purchase the fuel pump and sender assembly. Also just going to see how everything connects/dissembles etc. as I’m still a little hesitant to work on this s type.

 

In case this hasn't been mentioned yet, be very careful removing the fuel line connectors to the pump module as they're NLA.

Squeeze the pegs on either side of the fittings whilst pushing in, then they should release and you can remove them by slowly pulling up.

 

Fuel pumps are wear items you are making a mistake installing a used part. Especially a fuel pump that is as difficult to install as the one on an S-Type.
I would check prices and consider a new one only.
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I’m not installing used components, especially not a used fuel pump. Just went to see how everything is connected across the tank and also to see if I could get some spare parts like hoses, connectors, and the buckets.

 

a new fuel pump motor is like 9 dollars

slap it in a used bucket and away you go