On the 4.2 SC engine, is there a pressure test port on the fuel rail somewhere?

The jag X350 manual (section 310) seems to show the need to install a tee fitting (special tool 310-312), etc. Is there not a port with a shraeder valve somewhere? I did search forum threads on this, and found somewhere that there is a rail port on the NA engines roughly adjacent to the oil dipstick, but couldn't find a corresponding one on my XJR engine

Can fuel pressure sensor be accessed via scan tool? (I assume there must be a fuel pressure sensor somewhere, as the EFI system is apparently has a one way fuel line from the tank, with fuel pressure maintained by PWM signal to fuel pump(s)

Back Story:

My 07 XJR died on the road yesterday - in the worst possible place. By the time I had jockeyed it out of the roadway(start and die; start and die) and set the emer flashers etc, the battery was close to dead. Had it flatbedded home this morning. Assumed it was a fuel issue. Scanned and found zillions of DTC's, which I attributed to running the battery dead. But, no fuel pump related codes. And, FP fuses 24 and 33 are OK. Replaced the fuel filter, and I could hear fuel pump making up lost fuel when cycling ign key. Engine start and dies; starts and dies. Will not throw any codes (doesn't run long enough?)

So, I'd like to test fuel pressure. If OK, perhaps something like a crank sensor? Sure wish I could get it to set a code.

Any ideas?

 

What were the 'zillions of DTCs' you found? Did you clear them? If so, there is no way of knowing the possible issue(s).

Did you charge the battery fully? Once charged, it should have a minimum of 12.6 volts across the terminals. Lower voltage can affect the fuel pump.

 

Thanks NB

- Charged Battery? Did it yesterday before replacing fuel filter (12.68 VDC at battery this morning

- Codes? Yes; I cleared them. Mostly low bat voltage. Lots of stuff in ABS module ; yaw sensor error etc)

In the powertrain module before clearing:

Lean Banks 1&2
Crank sensor
Cam sensors
Bat voltage
Cat efficiency (this has been on for some time; illuminating CEL occasionally)

My mechanic buddy John Henry (who flatbedded me home) suggested that lean codes were probably fuel pump induced. It sure felt like a fuel pump - stuttering and recatching. The first time it died on the road, I was able to restart after 30 minutes and made it another 1/2 mile. Since then, it will usually start sort of normally, but always dies almost immediately, regardless of throttle position (within 1-2 seconds of starting, or less). My intuition is that pump cannot maintain any sort of rail pressure pressure once engine has started. Hence desire to test fuel pressure.

What if fuel pressure is OK (esp after engine catches)?

Researching forum threads (95% of which go nowhere), I'm wondering whether I might perhaps have an intermittent (now latched) electrical issue (eg, crank sensor). Adding to the complexity, it looks as if I've had mice under the hood, as there are bird food (sunflower seed) husks everywhere. Ahrggggh! So, I'm going to have to also check wiring if indeed there is a faulty sensor signal at the root of this. My issue is that the engine seemingly won't run long enough to set fresh DTC's. I may try to see if my Foxwell scanner can access live data such as crank position sensor. I gather that the CPS signal is not used during starting, but immediately after engine begins running?

Note to self: Move Rubbermaid tubs of bird food out to the tobacco barn; buy mouse traps and attempt to entice rodents out of your Jag with peanut butter

 

Check the wiring looms and connections for open circuits if there have been mice chewing on the wiring. The wiring, not a sensor, may be the cause.

Humane mice traps seem to work well, and no one gets hurt!

 

I'd like to pinpoint the problem before tracing wiring looms through hither and yon. And, before blaming the rodents

PS:

- I use the little trap door mouse traps (as I have dogs)

- Have you read the (I see you're a bicycle racer) Albert Champion book yet?

 

Focus on the areas you saw evidence of food and other debris.

I haven't read the 'Fast Times' book, but it does sound interesting.

 

You are correct there should be a Schrader v/v on the fuel rail.

On my jag (LHD) it's on the RHS near the front of the engine with

a blue plastic dust cap. Fuel pressure should be 55 psi or higher on an XJR.

 

Thanks everyone!

Looks as if my fuel issue may actually be electrical. See my "Getting Grounded" post for details

I've now done headstands, and am not able to find the fuel rail pressure tap port on my SC engine. I'll keep looking...