I go out the other morning and my '97 Disco would not start. Pop the hood, no fuel pressure. I have a gauge mounted on the fuel rail. Try a couple more times and she fired up. Drive across town, shut it off, starts up no issues. Go to my next stop and when I get back in, no start. I jiggled wires, pressed the inertia switch but no joy.
Had it towed home. Jiggle wires, pressed the inertia switch, took cover off at rear to fuel pump, cuss at it. Nothing really concrete I could find but in a bit it started back up. Drove down the block and back. Shut it off and tried it again but again, it would not start. I pulled the fuel pump relay and I noticed when I pulled the smaller connection and put it back in, the fuel pump ran for a couple seconds. I could see on the pressure gauge the pump working. I did this maybe five or six times then the fuel pump would not cycle. I thought maybe I burned up the relay.
I put the battery charger on it overnight. We had cold snap come thru but I did drive it across town so I wouldn't think it would be battery related. Anyway, I hot wired the fuel pump. It was working fine. The fuel pump is maybe a year old. Plug the connector back into the fuel pump and she fired right up. Idling fine.
My questions are:
Does the fuel pressure relay just die or can it be intermittent?
Could it be the inertia switch intermittently?
Could a low battery cause any of this?

I hate not finding anything and really do not want to be towed back home again.
Thanks,
dcphotos

 

I have an excellent low milage one - let me know if you want it ? $50 plus shipping instead of $175 new

 

disco96sd,
Thanks
($152 new w/ free shipping from Lucky8)
Let's make sure that's is indeed what I need first though.
Do you have any experience with a dead or dying relay?
Do they just go "belly up" or do they linger on like a bad actor getting shot in an old Western?
thanks,
dcphotos

 

If you like, the plastic cover on the relay can be removed. Then you can see the mechanism inside. Burned contacts can present intermittent operation, burned coil too. Some folks polish the contacts, other just replace the relay. Not a bad idea to have a spare relay anyway. Might be possible to test with a different relay from a different location on the truck, but the fuel pump relay might be one-of-a-kind.

 

JohnZo
Thanks for the reply. Yeah. this one is the TRW brand and it kind of a sealed one piece unit. I see where some, I think the LR original part has a "snap on" top.
I guess I could Dremel it apart but for now it's seems to be working.
I hate not knowing what "fixed" it (if is really is fixed).
Tomorrow I think I will try and clean up any and all ground leads I can.

I may buy a new one and swap it out. Looks the used market is about 60 bucks. Still an unknown unit and it's not worth $100.00 to me to be stuck out on a trail somewhere.

Not 100% sure it is/was the relay.
Thanks,
cphotos

 

Yep spare is always good

 

On my '97 D1, the wires going to the inertia switch were burned and I was getting the fuel pump would quit working once I shut off the engine. It would start working once it cooled down. I cut the wires and bypassed the burned ends (and inertia switch) No more problems. Just had to be careful not to roll the truck over.

 

I would check the wiring. I have had an issue with this. PO put in the wrong fuel pump. An electrical charge arched at the plug, and sort of exploded the contacts. Just a very tiny amount. I replaced nearly every single thing until someone suggested I replace the plugs because that was all that was left. I took a photo so I could compare. When I expanded the photo, I noticed that one of the female ends had expanded and this was making it so there was a loose connection. You might want to clean your connections and inspect thoroughly that all connections are connecting as they should. At the very least, this will eliminate that as a possibility, and it's free to do so.

 

DHTaylor,
Thanks for the reply. I did check the connections at the pump and cleaned them with contact cleaner. One pin did look a bit burnt.
I jumped the fuel pump and it worked. I haven’t had an issue since, going on two weeks now and at least 40 starts. So fingers crossed. I have a spare fuel pump relay and inertia switch now in case.
I hate not knowing what the issue was.
Cheers,
dcphotos

 

Thanks for the update/feedback. So, 40 starts indicates to me it was not a relay problem, since a failure of the relay will be an internal issue, not likely to self-correct. The burnt pin at the pump is likely the "smoking gun". If the pin contact is loose, that can cause arcing and intermittent function. Besides the contact cleaner, maybe see if the female side can be crimped tighter a tiny bit. Females can be difficult to understand. Make sure the internal surface is clean and shiny, or replace with new.

On the other hand, if any of the plug-in connections for the pump circuit were loose or corrosion built up, it could cause the same symptoms. So, possible that simply unplugging and plugging in again at the relay, inertia switch and pump, helped re-establish a clean solid current path to the pump. The movement wipes the corrosion away and gets down to clean metal. My favorite problems are those that fix themselves, so count your blessings!