Lucas 4CU ECU question

[lesliehedley]

Does anyone have the wiring diagram for the 4CU ECU? I am trying to fit an Emerald EMS in place of the 4CU. I have the wedge bible and I've managed to follow the wiring diagram in that for most of the pin connections to the ECU, but I can't work out what pins 4 and 20 are for. I know they are to do with the relays, but my knowledge of electrics gets a bit hazy with relays. I need to know whether these pins are ins or outs and if they have a voltage on them or not and what they control/detect, so that I can make sure I have their function covered on the Emerald ECU. Thanks for any help you can give.

Leslie
400SE

[HarryW]

Try the moggie plus 8 site they seem to have links to most things, they certainly have a very good one for the 14cux system.
www.gomog.com/plus8.html
I hope this helps, as always IMHO.
BTW this Emerald ECU thingy you're installing, does it have mapped ignition as well, just pondering

Harry

[lesliehedley]

Yes it does. Mapped ignition and fuelling. My ECU and air flow meter are both in need of replacement so I thought I'd try a more flexible approach.

[HarryW]

Any prices for the DIY approach , if you'd rather, email me via my profile.

Harry

[HarryW]

Checking the S bible it appears that the hand drawn diagram on page 306 (shpub confirm please ) shows a 4cu ECU and not the 14CUX as fitted to the V8S . In which case pin 20 goes to the throttle rest switch on the flapper and pin 4 is connected to the start injector and the starter relay amongst others , I would check this out with Steve Heath if I was you.
IMHO etc.............

Harry

[HarryW]

Ahhhhhh found it , page 9 of 12 for this pdf file link www.gomog.com/allmorgan/ljet/FIarts.pdf

Harry

[wedg1e]

On the 4CU, Pin 4 is the 12 cranking feed, and Pin 20 is not used. Is it DEFINITELY a 4CU you're on about, Leslie?

Ian

[EXCESSION]

Hi Leslie,

Can you keep us posted as to your progress ? I have been considering a fully mapped ECU for my 390SE but have been hesitant to take the plunge. I'd love to know the cost and improvement that you get.

Thanks,

Roger

[PAUL GOTTS]

My 400SE runs MOTEC programable ecu for the fuelling and ignition. As it was an early car, it had the flapper airflow metering system, which couldn't cope with all the demands of the 4.3 lump fitted - it could be adjusted to get the fuelling right at the top end, where it was originally running lean, but this ruined the fuelling in the low and mid-range. Rather than stay with this compromise, it went for the MOTEC approach, and managed to offset some of the cost by selling the old system. This has also meant that the effects of my subsequent tuning work on the engine can be fully realised by setting up the programme to suit (with the help of a rolling road and laptop).
Paul.

[petbeemer]

i have a little project started for the cux over on my forum, any tech heads are welcome to join

ETA

Link removed as it breaches the Rule of Posting 7

Edited by Big Al. on Sunday 7th September 12:37

[GreenV8S]

petbeemer said:

i have a little project started for the cux over on my forum, any tech heads are welcome to join ...

Given the similarities in the domain name, multiple references to 'piston heads' and 'petrol heads', 'gassing' forum etc and the fact that the basic purpose of the site seems the same as this one you could be accused of passing yourself off as pistonheads. Given that you seem to be the only person on the site I don't suppose the real PH is going to lose sleep over it any time soon, still you would be advised to choose a different name if you're planning to stay in 'business'.

[deetes]

Hi,

Here's a diagram I got when I was converting my 390 to Megasquirt.



I've got an Excell file with all the connections that were relevant to this conversion and would have posted that as well, but it's beyond my meagre computer skills. I could email it to you, if you want.

[deetes]

wedg1e said:

Ian

Ian,

Whatcha been up to? Haven't seen you on here for ages.

Thought you'd croaked, or worse still sold the Wedge.

Allan

[gsx600]

This might help if you are converting, seem to remember it's what the main pins do in tthe 4cu

1 Distributor Pulse
2 Throttle pot input
3 Vref to throttle pot
4
5 Gnd
6
7 O2 Sensor input
8
9
10 12V feed from Ignition
11
12
13 Coolant Sensor Input
14 Injectors Bank A
15 Injectors Bank A
16 Gnd
17 Gnd
18 Gnd
19
20 Output to Fuel Pump Relay
21
22
23 Gnd
24
25
26
27 Air Temp Sensor
28 Injectors Bank B
29 Injectors Bank B
30 Injectors Bank B
31 Injectors Bank B
32 Injectors Bank A
33 Injectors Bank A
34 Gnd
35 Gnd

[Waynester]

deetes said:

wedg1e said:

Ian

Ian,

Whatcha been up to? Haven't seen you on here for ages.

Thought you'd croaked, or worse still sold the Wedge.

Allan

Ian posted on this thread 5 years ago...!

Afaik he still has the wedge/390 - & he posted fairly recently.

[jmorgan]

Tis a bit of a thread resurrection to advertise ones web site?

Edited by jmorgan on Monday 8th September 08:02