excellent, thanks for solving that one. It's obviously something I overlooked in an earlier reply...it's an age thing I suppose.
Hopefully my next post will be to confirm that the engine runs.
 
....and on it goes !
Position to date is this. The ECU was sent to ECU Technologies for testing and came back A O K , however, the engine won't run unless I run a direct feed to the fuel pump and excite the injectors alternately bypassing the 14CUX.
ECU Tech immediately responded that it was missing an earth somewhere so we have replaced all 5 earths including the lambda sensors and run the cable straight back to battery neg.
Any helpful suggestions would onbce again be much appreciated.
 
My suggestion is check the wiring terminations again, the ECU should switch the fuel pump relay which appears that is isn’t that’s why the pump is inactive.
Also another relay “engine control load relay” that switches the injection is not working... maybe.
That s all based on my knowledge of my 3.9 with a bit of 3.5 for luck, another 3.9 discovery EFI wiring schematic attached showing the two relays.
You do have a ignition switched supply to the + of the coil don’t you, and from the Neg of the coil to term 39 of the ECU:)
 

Attachments

  • 72988618-B25E-4F30-8C1C-39526BECE385.jpeg
    72988618-B25E-4F30-8C1C-39526BECE385.jpeg
    393.4 KB · Views: 339
discool said:
My suggestion is check the wiring terminations again, the ECU should switch the fuel pump relay which appears that is isn’t that’s why the pump is inactive.
Also another relay “engine control load relay” that switches the injection is not working... maybe.
That s all based on my knowledge of my 3.9 with a bit of 3.5 for luck, another 3.9 discovery EFI wiring schematic attached showing the two relays.
You do have a ignition switched supply to the + of the coil don’t you, and from the Neg of the coil to term 39 of the ECU:)
Click to expand...

The ECU is indeed switching the fuel pump relay but nothing beyond . The engine relay is switching as it should and the engine will turn over and fire on the key
 
I assume that if it were a concealed isolator then the starter motor wouldn't function so I've ruled that out.
I wondered about the absence of the inertia switch as there was one originally on the Lotus ( recipient).+
I've installed a 6.8 ohm resistor in the coil + lead and changed the tune resistor to the correct value 470 ohm.
I've had the top sparky in the county on the car for 4 hours yesterday and he is completely at a loss. He checked all connections and they are good. He ended up checking all earths in the 14CUX and all good too. He put an oscilloscope on it to measure the strength of the signal from the ignition amplifier and all good.
I had all the injectors out yesterday and they all function properly, new seals, new filters.
Interestingly if you put a full earth on the injectors they function but with the low resistance earth they don't.

Not much hair left to pull out.

Thanks once again for your speedy reply. and please send any further suggestions.
 
O k if you’ve had a sparky look at the engine and can’t find the problem, then the not much more can be said from a Forum.
If the pump relay is switching but the 12v out isn’t arriving at the pump, then there’s a break in the wire to the pump or the pump isn’t earthed, as for the inertia all that does is cut cut the earth from the pump in an event of an accident.
Why the injectors ant opening... at the moment I don’t know. :(
 
Once again,
thanks for your thoughts. I have not rechecked the earth on the new fuel pump but will do so on Monday. I have to say that the pump starts its initial 5 second run when the ignition is switched on so I believe the fault to be somewhere in the injector circuit as If the injectors need something to "excite" them. I know they should receive this from the ECU but for some reason not happening. I actually returned the ECU to the specialists for further inspection because the sparky was convinced that the fault lay in the 14CUX.
Baffled from Bognor.
 
That’s it and so logical, the ECU should do the injector bank switching, it is a shame as your nearly there.:(
 
Thanks for the wiring diagram, it may provide the answer. I was working from a 1995 diagram and this one is post 1995. fingers crossed.
 
yippeeee ! she runs !
New wiring diagram is far more detailed and showed up something on fuel pump relay.
It seems that relay is powered and makes its switch thus powering 87 and 87A. Unfortunately the relay we used was powering 87A but switching off 87 simultaneously thereby down powering injectors.
I would like to find a genuine Rover fuel pump relay so will set about Rimmers tomorrow.

Thanks to all of you who have been so helpful in my endeavours.
 
springwood said:
thanks again. You're a star and this forum is fantastic.
Click to expand...
well hello again, four years older and beset with another hiccup which confuses this 75 year old's brain, your collective knowledge would be greatly appreciated.
The Lotus Excel hasn't been used much due to my illnesses but I am now getting back into it with renewed enthusiasm. I had the 14CUX reprogrammed with an EPROM similar to TVR and fair to say , it accelerates like "brown stuff off a stick" but here's the rub.
When the engine is hot it develops a total momentary cut out/stall at around half throttle...very dangerous in an overtake or pulling out into traffic.If I accelerate hard, back off perhaps for a tight bend, and then immediately back on throttle it shuts down for a second and then comes back in fine until the next throttle back when we go through the same scenario again ad infinitum.
Done all basic checks for loose wires etc., but nothing obvious. Thanks in advance.
 
well hello again, four years older and beset with another hiccup which confuses this 75 year old's brain, your collective knowledge would be greatly appreciated.
The Lotus Excel hasn't been used much due to my illnesses but I am now getting back into it with renewed enthusiasm. I had the 14CUX reprogrammed with an EPROM similar to TVR and fair to say , it accelerates like "brown stuff off a stick" but here's the rub.
When the engine is hot it develops a total momentary cut out/stall at around half throttle...very dangerous in an overtake or pulling out into traffic.If I accelerate hard, back off perhaps for a tight bend, and then immediately back on throttle it shuts down for a second and then comes back in fine until the next throttle back when we go through the same scenario again ad infinitum.
Done all basic checks for loose wires etc., but nothing obvious. Thanks in advance.

The above is my post from December 22, although it is an old post I have copied/pasted to save having to write all over again.
The car went out on a motor club run around North Somerset last Sunday and exhibited the above same fault several times over. All I can add is that it occurs under load and around 2000 rpm...like it takes a huge gasp of air but no fuel. This is momentary and by stopping and letting engine cool down for 15 minutes it starts instantly, drives beautifully but once hot it occurs again. No obvious clues apparent so I'm hoping that one of you knowledgeable Landy people can point me in the right direction.
 
Welcome back, an iffy EFI engine temp sensor can give give
a misfire or stall the engine when its reached working temperature.
Also maybe or not an iffy fuel temp sensor will give you the engine running temp sensitive issue.
 
Last edited:
Thanks for the welcome , it's nice to feel at home. The engine temperature sensor sounds like a good starting point especially as the temperature gauge was erratic and "stuck on the stop" sometimes but checking the engine it wassn't so hot thaat you couldn't touch the hoses. I'll check those in the coming week and report back.
 
You must log in or register to reply here.

Similar threads

xDParis64
Freelander 1 Converting from wasted spark to distributor (or Visa Versa)
Replies
0
Views
311
xDParis64
xDParis64
P
Series 3 Ignition Problem
2
Replies
23
Views
2K
Dippypud
Dippypud
S
asthmatic 3.9 efi needss help please.well hello again, four years older and beset with another hiccup which confuses this 75 year old's brain, your co
Replies
1
Views
1K
v8250
v8250
ChrisBduck
3.6L Land rover 90
Replies
2
Views
655
ChrisBduck
ChrisBduck
MunichDisco99
Disco 2 Air Suspension to Coils
2
Replies
31
Views
3K
MunichDisco99
MunichDisco99