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Rats! Now my D90 won't start. No power to fuel pump

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90 d90 fuel start
4K views 8 replies 6 participants last post by  jcasteel 
#1 ·
I seldom drive the Defender (1995 NAS Soft Top) and the other day when I went to start it the battery was dead. No problem that's why I have a dual battery set-up. Throw the switch and the engine turns as normal but won't start. Hmm that's odd. I hook up my wife's car for a jump and the D90 will still turn fine (of course) but won't start. As I'm hooking up my wife's battery I notice the distint odor of rodents and further inspection shows a nest and droppings in the battery compartment of the D90. Dang Rats!

Looking over the D90 there is another nest and droppings under the intake plenum and possibly some bare wires going to the injectors. After 2 hours I've confirmed that the wires aren't chewed through and I've reinsulated the slight gnawing marks with electrical tape.

Still won't start. (It cranks just fine).

Look under the instrument binnacle and darn it another nest and droppings behind the dash. Another few hours (half a day) and I've inspected the wires. Luckily none were gnawed through but there was quite a bit of wire insulation damage. So, I've taped it all back up nice and neat. Well, as nice and neat as electrical tape will look.

Still won't start.

It appears that I'm not getting power to the fuel pump. I don't see any voltage to the fuel pump fuse. When I jump a wire from the lights to the fuel pump then I can hear the pump spinning. So, like I said there appears to be a fault between the battery and the fuel pump fuse.

It appears that the thick white wire with blue stripe should be carrying current to the fuse. Back tracing the thick white wire with blue stripe (WH/blu) it looks like that comes from the inertia switch cut off. Leading into the inertia switch is a thinner white wire with purple stripe (wh/pu).

I also don't see any voltage across the inertia switch (Wait, I need to double check that). Does anyone know where the wh/pu wire comes from?

My memory says that on cranking, the fuel pump is energized for 5 or 10 seconds so there must be some type of clock mechanism. Is that clock before or after the inertia switch (Maybe it is in the relay.)

But my question is does anyone know where the white/purple wire comes from that goes into the inertia switch? Or, can you offer any other advice? Yes I have a gun and yes there are now 5 dead rats outside of the barn.

Dang rats.

My Rover is mad because I haven't been driving her lately.

John Casteel
jaypee@thecasteels.com
 
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#3 · (Edited)
John,
The ECU, fuel pump relay, and EFI relay are under the passenger seat in the tool box...i suspect another rats nest. I believe power flows from the fuel pump relay through the inertia switch to the pump on the w/p wire. The relay is controlled by the 14CUX ECU.
Rob
P.S. Rats can't nest in a moving Land Rover...drive it more!
 
#4 ·
It might be Friday, Oct. 28th, before I can look at the problem again.

Luckily the rats hadn't found the ecu under the passenger seat. I'm sure it was only a little time until I'd be cleaning rat droppings from there too. What does 14CUX ECU mean? It may be self explanatory once I look at it but does 14CUX refer to a specific terminal or wire on the ECU?

You say that both the EFI relay and pump relays are under the passenger seat. I know that there are two relays there. Is there a way to tell which relay is for the fuel pump and which is EFI? I can pull one relay and see if that deletes the voltage to the EFI fuse so if there isn't a ready answer to which relay goes where then I can at least figure it out. I currently have voltage to the EFI fuse.

When I crank the engine I don't have any activity on the diagnostic unit. I've disassembled the diagnostic unit and am looking directly at the LEDs. While cranking should the LEDs light at all?

Is there a sure way to know if the ECU is getting power?

I ask these last two question because maybe the problem is that a wire to the ECU has been gnawed? I'm sticking with the rats causing my problems until I need to look elsewhere. The Rover was running great before I last parked it.

So, four more questions.
1. What does 14CUX mean?
2. Which relay is which?
3. Should I see activity on the diagnostic unit while cranking?
4. How can I verify that the ECU is getting power?


Oh, and I know I should drive her more. I have my reasons, new child, I try to drive her at least once per week but she hasn't been out of the barn in 3 months. I think she's more angry that I haven't had her out in the woods for the last 6 months.


Thanks for your help so far.
 
#5 ·
Be sure to check fuses.

14CUX is the ECU label.

Check your grounds at the engine block. They usually have oil on them and may be more digestable to your visitors.

Good Luck
JP
 
#6 · (Edited)
As Pendy said, the 14CUX is just the ECU, it's like the 'model' we all use. One relay has a black plug, the other blue. I think the blue on is for the fuel pump... can anyone confirm that? These metal bosch relays are just 30 amp relays, although I've heard they are special and shouldn't be replaced with plastic relays permanently, but certainly can be for trouble shooting. You can get a 30 amp relay at any auto parts shop (autozone, etc.) for a couple of bucks. My FP relay let go going down the road... they just wear out sometimes. I'd check them for sure.
 
#7 ·
This is for a '97, so it may be different. But on mine, power goes from battery to starter (red). From another terminal on the starter (which is just connected to the terminal for the red wire), a brown wire goes to the fuse block. From the fuel pump fuse, power goes to the fule pump relay, then to the inertia switch, and then to the pump (all white/purple).

I sympathize. Mice did a bunch of expensive damage to a carborator in a truck I had once.
 
#8 ·
I'll follow the power from the battery forward. I was trying to go backwards from the fuel pump fuse. I have power to some (perhaps all but the fuel pump) fuses. Maybe there are two wires with power coming off of the alternator. One to the fusebox and one to the ECU. That is oversimplified but you get the idea.

I also need to double check all of the fuses. I checked them late at night and hopefully just missed one.

Thanks for your help so far.

John
 
#9 ·
Follow up to end the thread

Was posting another (semi-related) thread and noticed that I never ended this thread.

The problem was the fuel pump relay. Ordered mine from RN but I understand that there are much less expenses places from which to obtain the relays.
 
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