It seems I will be having to change out my secondary fuel pump. I have the XJR model and I am not sure which one is the primary and which is the secondary. The reason why I am only changing out the secondary pump is because I had just changed out both pumps about 6 months ago.

Here's why I believe why the secondary pump is bad. I have been getting hesitation on acceleration when I tried flooring the car. The car drives fine around town under normal driving with no codes. I couldn't figure out what it was, so I tried removing the primary pump relay and test drove the car around the block with it running on the secondary pump, but as I took off I can feel it stuttering and before even half way around the block the car died with the message "ENGINE STALL". Very similar to when the primary pump went out about 6 months ago. I plugged the primary pump relay back in and started up right away and drove normal again. Correct me if I'm wrong, but does this simple test justify that the secondary pump is bad?

Does anyone have a diagram showing which pump is which? I tried searching everywhere on the internet including this forum with now luck. Thanks much in advance

*UPDATE* I just started to hear a whine from the engine today. It's most noticable at a stand still, upon take off and when slowing down to a complete stop. I can hear it quite loud once I open the hood. Any idea what's going on?

 

I can't answer your direct question, but I would advise testing the pumps even if you have an indication of which is which since the wires could easily be crossed when installing the pumps. And, BTW, the effort involved in RR of the tank would make replacement of both of them would seem the better choice for my money.

While I suspect your diagnosis is spot on, before removing the tank, I would get a fuel pressure gauge with a hose long enough to be able to tape the gauge to the outside of the windscreen with the hood closed. Then I would measure actual pressure behavior. I would also test the voltage at the connector into the tank for both pumps and assure tt is not some wiring problem. Measuring the current draw of each pump (with the relay coil input jumped) will also possibly give some indication of what is happening. Is either pump drawing high or lower current?
I admit that I have skinned knuckles and scraped my skin every time I have removed a Jag tank, so I would try anything else first!

 

I agree, the acid test, so to speak, here is the fuel pressure at the engine.

The most common cause of your symptom, though, is a vacuum or air leak.

 

You need to remove BOTH fuel pump relays and 'jump' the terminals to verify that the pumps are inop or are operating normally. Run each pump with the engine OFF and check fuel pressure.

If you are going to all the labor trouble you might as well replace BOTH!!! as sparkenzap stated. Why did you only replace one when you had the tank out???

bob gauff

 

From the OP: "The reason why I am only changing out the secondary pump is because I had just changed out both pumps about 6 months ago."

Vector

 

When cold does your car crank a long time before starting? If it starts immediately this would indicate your secondary pump is working OK

 

It cranks normal and doesn't have a problem starting.

 

*UPDATE* I just started to hear a whine from the engine today. It's most noticable at a stand still, upon take off and when slowing down to a complete stop. I can hear it quite loud once I open the hood. Any idea what's going on?

 

The accessory drive is the first thing that comes to mind. There are tensioners, alternator, PS pump, water pump and AC compressor and of course the compressor pump all rotated at pretty high speed and all can get noisy. Removing the belts would be the first way to confirm or eliminate that area. Don't run the engine but a minute with the belt off to prevent overheating.

Something related to the original fuel issue is the pressure regulator. I have a propane regulator on gas fireplace logs that 'sings' or vibrates upon start up.

 

Read Mark's post #3!!!!!!!
Is the whine a vacuum leak? Listen around with one end of a small tube while the other end is stuck in your ear.
I think Mark might have nailed it!

 

There's no vaccum leak. I tried to get a fuel pressure test going but couldn't get it done because I rented a kit from an auto parts store to find out that none of the nozzle in the kit fits onto the nozzle on the car. Does anyone know what size it is or what test kit to look for so that it'll fit.

As for the whine, it now whines according to the gears and it's shifts (as the car accelerates you hear it whine, once it shifts gear it quiets down and pick up again as the speed/rpm picks up). Sounds like a supercharger noise but I know it can't be because the whine of the supercharge isn't that loud and it is under normal driving. Plus, this is new. I will be taking the belt off this weekend, but any ideas?

Would a whine following that kind of pattern accordingly with the speed/rpm and shifts if it is the belt?
Thanks again

 

I wonder if you are connecting to the right port. The schrader valve is a pretty standard test port for fuel gauges and every gauge I have seen matches.

 

You may be right because I am a rookie at all this. Where I tried to connect it to is: with a left hand drive car, facing outward from sitting inside the car, it is on my left hand side (bank 2) at the end of the fuel rail towards the front of the engine. There's a little blue plastic cap over it. Is that the one?