98 Disco I
4.0 GEMS
A/T
143k miles

For the past couple of weeks I've been having trouble starting it. Usually if I cycle the key to prime the fuel pump a couple of times it'll start right up and runs perfectly fine. Today I drove for about 20 mins, it sat for about 40 mins, I started driving for another 5-10 mins and it stalled out. I pulled over and sat for about 20 mins and it finally started back up. Drove for about 3-4 mins and stalled again. Did this a couple more times until finally (only 1.5 miles from home, of course) it wouldn't start at all and it didn't sound like the fuel pump was even priming.
Got it towed home and it started right up but now there's a pretty loud tapping sound coming from what sounds like to me is the head. It quiets down as the engine warms up more. The temp gauge is always just below 9 o'clock and I just replaced the faulty OEM reservoir.
I just went out to check fuel pressure after nearly an hour of sitting and got nothing. No fuel pump prime, no pressure at the rail.

I was originally thinking fuel pump before the stalling issue, but now I'm thinking along the lines of fuel relay or CPS. This still doesn't explain the tapping sound, though. Any thoughts?

Thanks

 

Valve train noise may go away as oil circulates. You can press a stick or long screw driver to your ear and touch valve covers to hear the innards more clearly. See tech sticky area for answer to oil questions, basically a jumbo low loss filter and Rotella 15W40. You would be wise to obtain (purchase or rent) an oil pressure gauge, it screws in where the oil pressure switch is. Mine, when cold, is about 44 at idle and 2000 rpm. As oil warms and filter bypass valve resets, remains 42- 44 at 2000, and above 20 at idle. Spec is 30-40 at 2000, and above 10 at idle. You would not want a failing oil pump.

As for that gauge, take a peek. It is very optomistic. You may want to read with a scanner or Ultra Gauge. Also with age may consider getting radiator flushed and rodded out, calcium build up.

I agree that it sounds like your crank position sensor dying, the CKP. If stuck, sometimes you can pour water on it to revive. When in failure, there will be no spark, another clue.

I like my 180F stat, runs 178-183 most of the time on highway, may get to 187 in traffic, will get above 200 if idling for very long periods.

Also like the food at Sting Rays, just up the road from you at Cape Charles, best Exxon you ever ate at.

 

I've got a stethoscope but not handy right now unfortunately. First thing I did with the truck was change to Rotella 15w40 and a large Mann filter. It's always had a slight tap but sounded more like it was the bottom end. This is a pretty violent noise right at startup now.

I've got no CEL through all of this still.

 

I use a broom handle, took it to keep SWMBO off flight status.... start up noise not good. Could be something with cracked rocker arm, etc. You may have to pull off valve covers to investigate, once you isolate which side.

 

I'd love to address the noise if I could get the dang thing to start again. I've got the fuel pump out now....I was getting 12v at the fuel pump connector and the ground had continuity when checked on the chassis so I figured the pump was dead since it wasn't making any noise and I had no pressure at the rail. Once I got it out and put 12v/ground straight to the pump it worked fine. I checked continuity through the pump carrier from the 4 pin connector through to the inside where the pump hooks up and all those were good. Any clues?

 

well...fixed that problem. got it started and it ran until warmed up then stalled out again.

now I'm back to getting no voltage coming into the pump and can't for the life of me figure out which relay is for the fuel pump (even with the rave)

 

I think the fuel pump relay is contained with the MFU relay in a little plastic box that is in between the ECU and AEL box.

 

I can put 12v straight to the pump while in the tank and it does nothing. I take it out and put 12v to it on the bench and it runs like a champ. this makes no sense

 

ground lead from pump assembly?

 

I've bypassed the connector on top of the assembly with +12v and ground straight to pump and it still only works intermittently. I guess that means the pump is toast.