That is a big clue. Look at page 246 in the RAVE manual. (Fuel pressure test procedure and recommendation(s) of which part(s) to replace if it fails) The check valve in a D1 is in the pressure regulator, not the pump (must have had Porsche on the brain, that's where they put it)

 

Checked fuel pressure at the rail - after cycling ignition to position 2 a couple of times, pressure showed approx 21lbs. Started the vehicle and pressure went up to approx 30lbs.

JUST MY LUCK!!! Drove the vehicle around the neighborhood to get vehicle up to operating temp, (101 degrees here), temp gauge showed very warm after 15 minutes. Pulled back into garage and shut car down - let the heat soak into engine compartment for 5 minutes - attempted to start the vehicle and it started fine. Let the vehicle run for a few minutes and shut it off. Waited 10 more minutes and tried it again....vehicle started fine. I hate to complain that the vehicle started but this makes the problem intermittent and unpredictable.

The engine temp was very warm, (close to redline). I'm letting it cool down and check the coolant level. I didn't notice if it was abnormally hot during previous stall and no-start events. There certainly wasn't any warning lights or overheating.

This vehicle has the GEMS ignition and fuel injector system so the fuel pump relay is located on the passenger side next to the ECM. Anyone have any experience with this relay causing intermittent problems? How about the fuel pressure regulator? Is the failure mode typically all-or-none or do they cause intermittent problems?

Starting to feel like I'm chasing my tail.............

 

stop toasting the engine .... borrow a scannrr above midpoint is overheating... borrow a scanner and you will see

 

Are you advising I borrow an OBD Scanner? What scanner are you referring to?

 

A scanner (not just reader) that can not only read codes but also the raw data. See pic. If you are near the end of the scale, you are way past overheating.

And the thought expressed here is that you stop allowing engine to get so hot that further damage will be done.

 

Savannah Buzz - I appreciate the advice. However, at the risk of admitting to CRIMINAL negligence, the coolant level was low. I will see how the temp gauge reacts after servicing the coolant.

 

I'm back Topped off the coolant and the temps appear to be fine (middle of the temp gauge). Took Savannah Buzz's advice and ordered a "scanner" - Utra-Gauge. Should be here this week.

The vehicle was driven on several trips around town and it started OK on each leg of the trips.....until last night. Same issue - My son drove the vehicle to work (8 miles) and it ran OK - Started OK after work - drove 2 miles, parked for 30 minutes, came out and vehicle started OK - drove 8 miles to grocery store and after sitting for 30 minutes WOULD NOT START. Let it sit for 2 hours, vehicle started OK and was driven back home.

-Does the 22lbs of fuel pressure when switch is on but vehicle not started indicate a problem with fuel pump? (understand f/p is expected to be approx 30lbs). It was 30lbs when engine started.
-My Disco has a Multi-function relay, (incl fuel pump relay), next to ECU in the engine bay on passenger side - are there also relays in the passenger footwell of this vehicle configuration?
- Do you guys agree that it is unlikely that the fuel pump would stop functioning intermittently and that the most likely cause of intermittent failure would be the relay? (after replacing fuel temp sensor and CKP)

Any idea what's going on at RoversNorth? I called a week ago and got no answer - left a message to call me back - no call back. Called again today and still no answer. I found the Multi-function Relay at Atlantic British but was hoping to find at least one other source for comparison.

 

Have you done the pressure test as outlined in RAVE (the one I referenced to) This still sounds like an intermittent insufficient residual pressure problem, the symptoms match exactly. Here's a portion of the manual

1. Remove fuel pump relay module. See Repair,Multiport Fuel Injection Relay
2. Start and run engine.
3. When sufficient fuel has been used to cause fuel line pressure to drop, injectors will become inoperative, resulting in engine stall. Switch off ignition.
4. Disconnect battery negative lead. .
NOTE: Fuel at low pressure will remain in system. To remove low pressure fuel,place absorbent cloth around fuel pipe at the filter during disconnection.
5. Connect the pressure gauge on the outlet from the filter, located on the chassis under the right rear wheel arch.
6. Reconnect the battery and turn the ignition to position II while observing the pressure gauge.
Results
Expected reading 2,39-2,672 kgf/cm2
Pressure drop-max 0.7 kgf/cm2 in one minute.
If pressure is low check that filter is not blocked and pump is operating satisfactorily. Then recheck pressure. If pressure is still low renew
regulator.
See Repair, Fuel Pressure
Regulator

This is a relatively common problem in many fuel injected vehicles, when I worked at a Porsche dealer, this problem was so bad, and the vehicles had multiple check valves in the system that weren't readily accessible, we modified the system to fool the computer into thinking the engine was cold so that part of the system would enrichen the system. Don't think I'd want to try this method on an OBDII vehicle though.

 

Gale, appreciate the quick reply. No, I have not done the fuel pressure test you reference. Since the vehicle would not re-start after it had reached operating temp, (starts fine when cold), I wanted to verify an operating fuel pump and fuel line-pressure. I checked the fuel pressure from the schrader valve on the fuel rail.

Due to the intermittent nature of this "failure-to-start-when-hot", I have been unable to verify the fuel pump is operating when the vehicle won't start. Every time I have a fuel pressure tester available, the vehicle starts fine.

 

You might want to see if you can find a gauge that you can leave attached to the fuel rail as you drive it (I have one with an extra long hose so I can run the hose out the hood cap and duct tape the gauge to the outside of the windshield, gotten some strange looks with that setup). What could be happening is the check valve is sticking open at times. It's basically a spring and ball assembly that opens with fuel pressure and closes and maintains pressure when the pump shuts off, this little spring and ball affair could have dirt, the spring getting weak, or something else that prevents it from sealing. The system will leak down but the logic (I know, logic and Rover isn't supposed to be used together) is that by the time the fuel pressure has bled off, the engine will have cooled down enough for the ECU to put the engine in "cold start" mode which is why it starts when cold. The regulators aren't cheap, I found one at Rovers North for $155.-, British Pacific wants $167.- but interestingly enough there is a dealer that sells wholesale online and that part is only $128.-. (so much for assuming the dealer is always more expensive, it pays to check) I've ordered parts from them before so they are legit. 1998 LAND ROVER DISCOVERY Parts - Land Rover Parts Center - Call (800) 574-9217 for Genuine Land Rover Parts and Accessories

Of course your problem could be something else entirely so you need to narrow it down before spending money on parts you don't need. I could be something electrical that is intermittently failing with heat. It could be as simple as the fuel pump locking up when it gets hot (after you shut it off), I've seen that too. Hope this is helpful.

Edit: Been doing a little more looking around, it appears that this is the pressure regulator that fits your truck (not the one I referenced before) http://www.roverparts.com/Parts/ERR6185OE.cfm,
and they're on sale!! it's a closeout but it looks like they have a lot of them in stock, Hmmm, wonder if that means anything? Anyway the OE part number is ERR6185