In the second post of this thread plums describes the function of the secondary fuel pump. When I say that I primed it, I mean that I turned the ignition from Off to On and allowed the secondary pump to prime the fuel rail for several seconds, and then remove the key and repeat.

RevSam describes this process in his fuel system check valve thread. I believe he performs it regularly to overcome his starting issues.

https://www.jaguarforums.com/forum/x...el-pump-85882/




and plums, I really appreciate that comment. I saw that in another thread and I do plan on doing that this weekend. I haven't pulled the relay yet to see the pin configuration for myself, but I believe the two perpendicular pins need to be jumped, correct?

Hopefully it'll be cold so I can perform this test while its giving me the starting problems.

 

The relay circuit is drawn on the side of the relay. Make sure you get the right pins because one of them is driven by the ECM. You don't want to be fiddling with that as it could get expensive. The circuit diagram should be around here somewhere.

 

See if this fuel pump check helps

Link JagRepair.com - Jaguar Repair Information Resource

It seems to me that if you monitor the actual fuel pressure on your system you will know what is going on.

 

Alright.. since my last post:

Based on some relay checks, I thought I had an intermittently bad secondary fuel pump. To remedy this, I went in and replaced BOTH fuel pumps with Bosch pumps from eBay. After the initial start, the car ran well for a day (multiple starts and stops).

Then the next morning.. nothing.

Yesterday I bought a fuel pressure gage. I hooked it up this morning and it said 0 psi initially, and then it went up to 20 psi when I primed the system. It would never go above 20 psi though...

Thoughts?

 

You should have pressure greater than 20psi! I think you need to look at your fuel pressure regulator.

 

If you had diagnosed a bad secondary pump, it makes sense that your still have a starting trouble, because the secondary pump alone will not prevent starting.

As Gus said, you fuel pressure is very low and I agree the regulator is a prime suspect, but you should also replace the the inexpensive fuel filter.

 

The fuel filter was the first thing I did

I understand the function of the fuel pressure regulator and where it should be located in my car. I also looked at a picture of one on rockauto.com, but I can't locate it in my car..

I see the fuel lines going into the rail on the rear driver side of the motor, but it goes into rubber lines that appear to go under the car. Do I need to trace them back further or am I just overlooking something?

Does anyone have any pictures or any descriptive pointers? Maybe the coolant reservoir is just blocking my view.

 

See if this link helps http://jagrepair.com/images/AutoRepa...0Parts%201.pdf and go to page #95

 

On the 2000 XKR it is under the right rear (passenger side) charge cooler. You should be able to positively identify it by the black rubber vacuum line going to it (actually check that line...that could be your problem also.)

I have never tried to remove it on this car myself, so I am not sure it it requres removal of the charge cooler.

 

Thank you sir. I found it last night. It was under the intake pipe near the throttle body. I removed the two 8mm bolts that secure the pipe to the TB and I could see it.

It seems to be held in by a single 8mm bolt, which I removed, but it didn't come out easily. It was dark so I didn't struggle with it and I just left it in.

I checked my fuel pressure this morning and it was almost at 0. I primed the system and the pressure went up to about 12 psi, primed a second time, it went up to 30 psi. I primed it a couple more times and it reached a maximum of 42 psi (it would go up to 45 but then the pressure would get purged off, I don't know if this is OK or if that was due to my leak).

I still believe that my issues are temperature dependent, which leads me to think that this is an issue with an o-ring somewhere in the system. I believe if the temperature was in the 20's or 30's this morning I wouldn't have seen the pressure rise like it did when I primed the system.

I will attempt to remove the regulator tonight and inspect it for any defects. I think it has two o-rings on it, which may be deteriorating and/or shrinking in cool temps. The vacuum line looked fine but I will remove it too and see if it has any leaks.

 

See the recent thread started by Maxwdg.

In his case it was the fuel pulse damper and the viton seal for it. But, generally the same idea.

 

You have mentioned that the after the pump change, the car ran fine. Did it have full power? If it did, I would dismiss the fuel pumps and look at the control system for the pumps. This and the battery are the only temp sensitive areas that could cause the problem. It is possible that the fuel pump module is bad. If the pumps were bad, it would never run "fine". Pump failures are seldom sporadic. Look at your wiring schematic and track back the pump power and control to each module and check out that module. Also look at the relays.