Fuel pump power issue...

sierrafery said:

Yes, i was just clutchig at straws with that as i dont have anything pre-95

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That pic was of my 1997 disco, with all the engine bay looms disappearing through the bulkhead and into the footwell.

OK, been out there cleaning earth terminals. Maybe a waste of time but I feel better for doing it.
I turned power off removed the plug to the ecu. Then dismantled ecu plug body to reveal wiring. Then reconnected power & tested with ignition on.
There is a group of black wires together. Voltage between them & 15 (brown) is 11.56
Voltage between them & 19 (white/red) is 11.35

sierrafery said:

Might be that ... can you read the part number of the ECU? it should have a label on it
View attachment 203383

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Here is a picture of the ecu..

Was that with plug connected to ECU or not? the battery voltage directly on the battery is also below 12V?

No, the plug was not connected. Should I do it again?
The vehicle is across the road in a car park....I will nip over & check the voltage on the battery now....

Voltage across the battery terminals now 11.60

Then the ECU is very suspect, though you should measure with ECU connected too just to be 100% sure that the voltage doesnt drop due to a bad contact which is quite unlikely but possible. Good luck, at this point i can't help you more.

sierrafery said:

Then the ECU is very suspect, though you should measure with ECU connected too just to be 100% sure that the voltage doesnt drop due to a bad contact which is quite unlikely but possible. Good luck, at this point i can't help you more.

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Thanks for your help up to this point. I
I'm keen to understand the readings: which part of the readings make you think the ecu is very suspect?...& what should the readings be?

It's suspect cos it gets the necessary feed but it doesnt do it's job to trigger the relays and injectors, unless it's a wiring issue... it's explained in post #73

sierrafery said:

It's suspect cos it gets the necessary feed but it doesnt do it's job to trigger the relays and injectors, unless it's a wiring issue... it's explained in post #73

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Aah OK, thanks. So the power to it is OK, well that's something I guess.
I will get another ecu if I can then & try it. Cheers.

JDZ2 said:

So, I'm writing all this to make sure I'm measuring correctly:
The black plug relay ( the main relay ) with the ignition on & with an earth supply with a cable directly from the battery
86 (with thick brown wire) reads: 11.92
85 ( with blue/red wire ) reads: 1.87

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Not to sad, if your battery

JDZ2 said:

OK, been out there cleaning earth terminals. Maybe a waste of time but I feel better for doing it.
I turned power off removed the plug to the ecu. Then dismantled ecu plug body to reveal wiring. Then reconnected power & tested with ignition on.
There is a group of black wires together. Voltage between them & 15 (brown) is 11.56
Voltage between them & 19 (white/red) is 11.35

Click to expand...

Not to sad a voltage drop if you battery is reading 11.60v + - depending how accurate your meter is, but is not that important in the scheme of things, as there is voltage available.

sierrafery said:

It's suspect cos it gets the necessary feed but it doesnt do it's job to trigger the relays and injectors, unless it's a wiring issue... it's explained in post #73

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Well, an update:
I sent the ecu to that company you put me on to. They just called to say that it is working as it should, no problem at all.
So, the mystery continues! On it's return, any pointers as to what I should try / test next?

I'm sorry that your saga continues but at least you know the ECU is OK. As i said in previous posts this kind of behaviour is specific for immobilised ECU but unfortunately i dont know how the immobiliser works on so early modells. Is the key fob working ?

Check voltage on the ECU plug while it's connected and ign. on across pin 19 positive(white/red) and pin 12 negative(blue/red)

sierrafery said:

I'm sorry that your saga continues but at least you know the ECU is OK. As i said in previous posts this kind of behaviour is specific for immobilised ECU but unfortunately i dont know how the immobiliser works on so early modells. Is the key fob working ?

Check voltage on the ECU plug while it's connected and ign. on across pin 19 positive(white/red) and pin 12 negative(blue/red)

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OK, thanks I will try that when the ecu arrives back. Yes, the key fob works OK, I only have the one but it works.

SHE'S FINALLY RUNNING & SOUNDING SO SWEET
Firstly, my thanks to sierraferry, discool & the others who have taken the time & trouble to provide advice & help with trying to solve the problem.
The great news is a have just taken her for a first drive ( this is my first ever 4x4 ) & she drives really lovely, I am delighted.
So, the only issue is I don't know what I did to solve it! After getting the ecu back, putting back in, I decided to go through all the wiring again, took the loom apart, traced every wire I could & where I could cleaned up any dodgy, slightly discoloured terminal etc. I didn't find anything I can say was conclusive but I connected it all back up, secured the wiring, connected the recharged battery which is crap ( have ordered a new one ) & she fired up on the first turn....I can't tell you how pleased I am. I can now spend the next 12 weeks or whatever it is during this "lock down" cleaning her up to the standard I am used to......Stay well everyone & to those NHS workers on the forum, a big THANK YOU.

An iffy electrical connection perhaps, I bet it was a big surprise, when u heard the engine roar, shame we don’t know where, but ha ho it’s running. So well done!