I am totally confused. I have a 98 VDP. I love her. I've had the engine rebuilt twice and I don't plan on selling her anytime between now and my death. Lately, the problem has been fuel delivery. I just replaced my pump and strainer, again. Now, I can only get her to run if I jump the terminals on the fuel pump relay with a small wire with spade connectors on the ends. She starts right up. If I put a relay in, I get no start. Here are my thoughts, please please tell me your ideas/opinions, anything that can get her back on the road without having me have to open the trunk, install the wire, open the hood, check for fuel pressure (sometimes it takes a few tries), close both and then get in the car and go. I believe the wiring harness in the tank is to blame. It has a slight brown discoloration and I've been told it has a resistor in the little box. I think I'm not getting adequate voltage to the relay and then through the resistor to get the pump to actually pump. When I have a relay in place, I can hear the pump, but there is no fuel pressure. I think when I use the jumper wire, more voltage is actually transferred through the resistor making the pump run. Is this logical or am I just making this up? I know your time is valuable, but I just can't afford to bring her in for a diagnostic at the dealer (baby on the way due in 3 months). Please, if you have a few moments, I would greatly appreciate your guidance. Thanks for your help and if you ever find yourselves in Philly, my doors, both home and garage are always open.

 

Welcome to the forum!

Have you tried swapping the relay with another? They are all the same. Might be just poor contact within the relay.

 

The relay could be faulty as suggested above.

The discoloration on the internal tank wiring is not a good sign. This has been written about before. The inline device is a noise suppression circuit. You can safely eliminate it by using fuel rated wire (teflon/tefzel insulation) of sufficient gauge. (12 to 14 AWG)

The noise suppressor is a bit of overkill as no one has ever mentioned any objectionable radio noise after chopping out the suppressor. In any case, you can use ferrite chokes on the external wiring.

 

I have tried every relay in the car. I looked around for a replacement in tank pump harness and the best prices I can find are about $100. Personally, I think that's crazy for a little over a foot of wire. I'd like to try making my own harness and eliminating the noise suppressor. This might be a stupid question, but can I acquire fuel rated wire at most national parts retailers, like the boys or the zone? And, what is a ferrite choke? Ill look both up on google now, but if you have any tips or info you don't think I can learn from a YouTube video and a few online articles, I would greatly appreciate the guidance.

Here is another explanation I wrote of my problem to a supposed jaguar expert online. Ill report back with his 2 cents. I think I did a better job of outlining the issue on my second attempt for some tutelage. Thanks guys!

1998 jaguar vanden plas : 4.0 : 57,000 miles : replaced head gaskets : timing chain/tensioner/water pump/thermostat upgrade

I know this car well. I restore antique British cars, so Im not a novice when it comes to turning wrenches. This problem has me completely stumped and is on the verge of retiring my car permanently. I had a fuel pump die so I pulled the tank and replaced it. Now, the only way I can get the car to start is to pull the fuel pump relay and use a wire with two spade connectors to energize the pump. This works half the time. Many times I can hear the pump running after installing the jumper wire but still have 0 pressure at the rail. The car will not run with a relay installed in the fuel pump relay spot. Put a jumper wire in the two terminals and within a few tries she's running perfectly. What am I missing? I'm so confused and frustrated. Every time I want to use the car I have to open the trunk install the wire. Open the hood check for pressure, go back and forth a few times till I can close both and get in and go. At that point, I don't want to turn it off bc this starts all over again. Please help!"

 

A ferrite choke is just a ring made of powdered metal. You wrap a few turns of the external wire through the ring. They are probably obtainable at radio shack. And probably not required. I don't have the suppressor or a choke.

The teflon/tefzel insulated wire can be obtained online from aircraftspruce.com who sell a wide range of materials and tools that are of interest to serious car enthusiasts. It is also available on ebay or electrical supply houses. Home Depot also sells a type of wire using the UL rating terminology that *may* be suitable. What you want is something that is rated for gasoline immersion.

If you are wanting to keep the terminals that attach to the top flange plate, then cut the pigtail and crimp on the new wire using a proper crimping tool.

If you are wanting to replace the wire completely, do not drill a hole through the flange and run the wire through. The fuel will wick along the wire and come out somewhere near the fuse box. Not recommended for obvious reasons.

The way to do it is to drill holes in the flange for a brass screw and terminate the wires on either side using ring terminals. That interrupts any tendency to wick. Seal the hole/screw joint with epoxy or silicone. Again, use a proper crimping tool. Pliers don't cut it.

but, if the car runs with a jumper, but not the relay then it should be fixable without replacing the link lead. It does not matter that you have tried other relays. Get a new genuine Jaguar relay, then check that the relay is actually closing and passing juice. All the relay does is complete the circuit between those two pins that you are jumpering.

 

Just as a matter of interest what pump did you use to replace the old one? Is it a good one that's right for the car ? Obviously something you did during the change over has messed up the power to the pump or maybe the pump itself is the problem, maybe the relay isn't allowing enough juice through to get that particular pump going...... or are they all standard voltage?

I had similar no start issues with my car after a fuel pump change this week... still not sure how I got her working it may have been a loose relay we found.

 

Where would you check for voltage to see if relay is allowing current/voltage to pass? At the white connector at fuel pump above tank? If so on which 2 wires of the 4 at connector?

Also if relay is bypassed with jumper wire, does that eliminate all the other things that can impede fuel pump from working? In other words with a jumper in place (and assuming no open wires from there up to pump connector) if pump still doesn't work it HAS to be bad fuel pump?

 

http://api.viglink.com/api/click?format=go&key=d92373423436cd6f57cd0cabc68478 54&loc=http%3A%2F%2Fwww.jaguarforums.com%2Fforum%2 Fxk8-xkr-17%2Fxk-8-stall-wont-start-fueling-issue-98582%2F&v=1&ref=http%3A%2F%2Fwww.jaguarforums.com %2Fforum%2Fsearch.php%3Fsearchid%3D2230582&libId=e 9004d84-8205-4683-b1f4-7fe4d61c61c0&out=http%3A%2F%2Fwww.jagrepair.com%2F FuelPumpVoltageChecks.htm&title=XK%208%20stall%20a nd%20won't%20start..%20Fueling%20issue%20-%20Jaguar%20Forums%20-%20Jaguar%20Enthusiasts%20Forum&txt=JagRepair.com% 20-%20Jaguar%20Repair%20Information%20Resource&jsonp= vglnk_jsonp_137414877062012

This is for a 99 xk8 not sure if its any use to you

 

KellyXK8 that is GREAT information, the best I've gotten so far after posting a couple of new post about this problem and asking questions on one or two others that seemed to pertain to my problem. So, THANKS AGAIN!!

Awesome picture too!

 

just passing on info that other members gave to me on the problem, Glad it helps you.