Started, quit, and the mystery began...

Spark6

Active member
Oct 31, 2020
27
3
Pittsburgh, PA
Howdy,

I’m new on the block. I’ve been messing around with the search function all day, but can’t quite find the answer to my question, so here I am!

My wife and I just purchased a 1998 Disco 1 (both of our first experience with Land Rovers!) with 122k as a toy/over landing project. It’s a runner, or so we thought, and our plan was to treat it as a third car/winter car while we slowly turned it into the adventure-rig we’re looking for. We drove it around for a couple hours the first day we got it, took it to go hiking, ran some errands, all without issue, until we went to the grocery store. Having left it for twenty minutes we came back to the rig, loaded up, fired up, only to have it surge, stumble, and quit immediately. Subsequent attempts to start lead to the same result. It would crank, catch, idle, run rough, lose RPM, and die. Good. Hood up, wife in the driver’s seat, me up front, I could occasionally keep it running by blipping the throttle, but only for a few moments. I did notice, however, that there seemed to be a “hissing” sound, like a vacuum leak, towards the left side of the engine bay. Couldn’t locate it though. Kept having the wife attempt to restart at intervals, hoping to find the leak. Couldn’t. Same stuff. Loses RPM, runs rough, misses, and dies. At my wits end, and purely on a hunch, I disconnected the intake from the air filter. (Did NOT disconnect any wires, however!) What do you know? Truck starts right up and idles away happily like it hasn’t a care in the world. More concerned about getting home than looking a gift horse in the mouth, I push all the guts under the hood, leave the air box disconnected, put my wife in the passenger seat, and drive home... without so much as a hiccup. Safe in the driveway, and without shutting down, I reconnect the air box - no problem. Truck idles away happily. I check the filter - it’s clear. Check the air box inlet - it’s clear. Still a hissing from somewhere in the top left of the engine bay. I’m starting to think my air box disconnect trick has nothing to do with the restart.

Any ideas what I’m dealing with here? I’m figuring I have a vacuum leak somewhere that is messing with the fueling on startup. I’m inclined to just start replacing vacuum hoses. Am I on a goose chase?

Good news - the wife loves the truck and I can keep it. Bad news - she’s named it, and so I HAVE to keep it. Help! :D
 

Vegas99D1

Well-known member
May 5, 2009
155
2
Plano, TX
I'd suggest replacing ALL vacuum hoses, the truck is over 22 years old...vacuum hoses are probably most if not all original. Is there any service information from the previous owner you can go off of for how well they were maintaining the truck? This will be a great indicator as to what you need to focus on maintenance wise. If you haven't already, get the engine oil, transfer case, diff, and trans oil changed.

There are several online Rover specific shops that can get all the vacuum hoses needed for you as a "kit". I'd also recommend going through the cooling system and replacing the coolant and all hoses as well.
 

Spark6

Active member
Oct 31, 2020
27
3
Pittsburgh, PA
Truck has been pretty well cared for, based on the previous owner's report. He bought it for his wife, put a bunch of money into replacing brakes, shocks, valley gasket, only for her to decide she'd rather have a Merc G... -_- He's not a LR guy, so he didn't want it for himself. The vacuum line kit sounds like a great place to start. I'll check into that. Thank you!
 

4Runner

Well-known member
May 24, 2007
461
27
Boise Idaho
I don’t know. It will run with a bad MAF just not well. I am completely guessing but that sounds more like a flaky fuel pump/ wiring issue.
 

4Runner

Well-known member
May 24, 2007
461
27
Boise Idaho
I change my fuel pumps at 130k just because it’s one of the few things that will shut you down with few options.
 

Spark6

Active member
Oct 31, 2020
27
3
Pittsburgh, PA
Fuel pump was one of the other items changed by the last owner... but I feel like I'm smelling a bit more of a gas smell at the back of the vehicle than I'd expect, even from an old rig. Might be worth poking in there and checking that it was done properly...
 

simondewing

Active member
Feb 10, 2020
38
8
Texas
You could also check the stupid rubber seals under the back of the valley (intake) gasket.
They become hard and brittle over time then crack creating a major vacuum leak.
As air is bleeding into the intake manifold after the MAF sensor the ecu gets confused.

Rgds

Simon
 

WaltNYC

Well-known member
Mar 3, 2010
520
26
NYC
" Fuel pump was one of the other items changed by the last owner... but I feel like I'm smelling a bit more of a gas smell at the back of the vehicle than I'd expect, even from an old rig. Might be worth poking in there and checking that it was done properly... "

The gasket between the pump and tank may be shot, or may be the wrong gasket. In 1996 LR put additional emissions stuff on these trucks and one change was the fuel pump and gasket.

I'd also check all the PCV hoses/tubing to be sure.
 

Spark6

Active member
Oct 31, 2020
27
3
Pittsburgh, PA
Great notes. Valley gasket was very recently replaced by po’s mechanic. But I’ll poke back there too. Truck is on a 2” lift and I’m working in my apartment parking lot, so my workspace isn’t ideal.

The plot thickens though... after leaving the truck for four days while I was at work, I went to start it today... cranks VIGOROUSLY, but doesn’t so much as sneeze. My key fob is working and the red light under the speedo is not on or flashing, so I don’t *think* I have immobilizer trouble? I’ve tried pushing the inertia switch under the dash, thinking mebbe the fuel pump had tripped... no good. Props to the battery. It’s been cranked probably thirty times as I’ve beat my head against this. I can’t figure out how I’ve gone from running and driving perfectly to this in such short order!:unsure: Gotta wait for the wife to get done with work so I have someone to crank the key while I pull a plug and check spark, but I’ve got this nagging instinct that this is a lack of fuel problem... I hate the stuff but maybe some starting fluid in the intake would confirm that for me...
 

Spark6

Active member
Oct 31, 2020
27
3
Pittsburgh, PA
Update: motor will catch and run on starter fluid sprayed through the intake. Stuck my head in the pax rear wheel well while wife turned on the ignition. I don’t hear any clicks or noise from a fuel pump. I’m starting to really think I’m not getting any fuel. What would cause the pump not to turn on other than a bad pump? What should I check before I try to open up the fuel tank? :poop:
 

lennonjon

Well-known member
Jun 21, 2010
61
3
Ashtabula, OH
This might be a silly suggestion, but you mentioned hearing a hissing sound coming from the left side of the engine. Did you check to make sure the Schrader valve on the fuel rail isn't leaking? A few weeks ago I was having trouble starting my Disco if it sat for more than a few minutes after turning it off. This was after replacing the fuel pump, so I thought perhaps it was a faulty pump. When I went to check the fuel pressure at the rail and removed the cap off the valve I noticed there was some gas in there. Replaced the valve core and have had no issues since.
 
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pinkytoe69

Well-known member
Jan 14, 2012
1,366
84
minnesota
What should I check before I try to open up the fuel tank? :poop:
The fuel pump connector is accessible from the drivers rear wheel well IIRC. Make sure none of the pins have backed out.

It isn't too difficult to get to the pump access cover if you want to try to jump the pump.

Did you download the RAVE?
 
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Spark6

Active member
Oct 31, 2020
27
3
Pittsburgh, PA
The top of the motor is dry, but I’ll check it this AM for fuel leaks at the Schrader valve. I DID find what looks to a cracked vacuum line coming off of the fuel regulator, which I’m thinking must have been the source of the hissing, so I’ll replace that today. I spoke to the PO, who hadn’t experienced a fault like this during his ownership of it, but confirmed that the fuel pump was replaced in the last year or two. Having done some more research, I’m thinking the fuel relay may be the culprit. Ours is an AEL truck, so naturally, we have the expensive relay!

I thought I’d downloaded the RAVE - I have an 873pg PDF called the Discovery Workshop Manual, but the more I read the forums, the more I am suspecting that I don’t have the whole thing?
 

Spark6

Active member
Oct 31, 2020
27
3
Pittsburgh, PA
Update: Found and downloaded the full RAVE. Will start going through that - it looks like a doozie!

Checked the fuel rail shrader valve. There is fuel there, but next to no pressure. (Fuel dribbled to the top of the valve, but didn’t spill or squirt out of it. I’d just attempted to crank it, so I would have expected a bit of pressure let-off?)

Definitely had a vacuum leak on the hose going to the pressure regulator. Not massive, but significant. I’m off to get a new hose.

I’m still suspicious of the fuel pump relay. I’d like to be certain though - $150 is a fair chunk to just throw at a problem on a hunch. I’ve been mashing the inertia switch each time I’m under the hood - hardly feels like I’m even pressing a button though. I’ll jump that switch when I get back to see if it’s bad, but I kinda doubt it.
 

lennonjon

Well-known member
Jun 21, 2010
61
3
Ashtabula, OH
Update: Found and downloaded the full RAVE. Will start going through that - it looks like a doozie!

Checked the fuel rail shrader valve. There is fuel there, but next to no pressure. (Fuel dribbled to the top of the valve, but didn’t spill or squirt out of it. I’d just attempted to crank it, so I would have expected a bit of pressure let-off?)

Definitely had a vacuum leak on the hose going to the pressure regulator. Not massive, but significant. I’m off to get a new hose.

I’m still suspicious of the fuel pump relay. I’d like to be certain though - $150 is a fair chunk to just throw at a problem on a hunch. I’ve been mashing the inertia switch each time I’m under the hood - hardly feels like I’m even pressing a button though. I’ll jump that switch when I get back to see if it’s bad, but I kinda doubt it.
If there's fuel dripping out of the valve and no pressure then you need a new core. It's not allowing fuel pressure to build up and hold in the fuel rail (this was the issue I had). Just replace it with a core from a bicycle tire and that should fix that issue at least. I've seen people suggest carrying a few cores in your glovebox, as these can and do go bad.
 

Spark6

Active member
Oct 31, 2020
27
3
Pittsburgh, PA
If there's fuel dripping out of the valve and no pressure then you need a new core. It's not allowing fuel pressure to build up and hold in the fuel rail (this was the issue I had). Just replace it with a core from a bicycle tire and that should fix that issue at least. I've seen people suggest carrying a few cores in your glovebox, as these can and do go bad.
Sorry, I should have been more clear! The fuel only dripped when I triggered the valve. The valve core itself seems to be functional. Good idea to stock up on those though. I’ve seen enough of them go bad in airplane tire tubes over the years to have a healthy distrust of them.
 

lennonjon

Well-known member
Jun 21, 2010
61
3
Ashtabula, OH
Sorry, I should have been more clear! The fuel only dripped when I triggered the valve. The valve core itself seems to be functional. Good idea to stock up on those though. I’ve seen enough of them go bad in airplane tire tubes over the years to have a healthy distrust of them.
Ohh gotcha. Yeah, so it sounds like you don't have pressure at the rail. A properly pressurized rail will spit gas in your eye :D
 

Spark6

Active member
Oct 31, 2020
27
3
Pittsburgh, PA
Ohh gotcha. Yeah, so it sounds like you don't have pressure at the rail. A properly pressurized rail will spit gas in your eye :D
That’s what I thought!!! Okay, terrific, so if I don’t have pressure to the rail, then that backs up that I’m not getting the go-juice from the pump. Which, if my understanding of the system is right, means that, assuming continuity of all the wiring, either my inertia switch or my fuel pump relay is preventing the fuel pump from running, OR the pump is bad. Since the car was driving recently and has a relatively new pump, I’m thinking inertia switch or relay. I’m going to check the plug on the fuel pump, and then pull the plug on the inertia switch and jump it... I’m definitely running out of juice in the battery so I’m hoping not to have to try this too many times! Hahaha.
 

Spark6

Active member
Oct 31, 2020
27
3
Pittsburgh, PA
So... you know that moment when things start unravel a bit? Somehow, I don’t think this fuel pump was, “replaced a year or two ago.” B53BC2B9-0030-4AE4-BECD-A1B11E1F79DC.jpeg
Wires look good. But that’s about all that does. I think at this point, it’s pretty much a matter of course that I need to replace the pump/sending unit. Whether or not that’s the actual problem is anyone’s guess, but I can’t in good conscience assume that anything else is the culprit when this thing looks the way it does.:sick:o_O