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jonny

Member Since: 10 Mar 2013
Location: North Wilts
Posts: 154

A quick search suggests that pin1 on the back of the speedo is the speed output to the ECU. Yellow/Pink wire.

Pin 13 on the Engine ECU (Black C0658) is linked to the instrument pack by via connector. Yellow/Pink wire.

See: https://nas-row.com/index.php?threads/td5-...#post-7006

12th Dec 2024 2:47pm

Pepsyseventy

Member Since: 12 Dec 2024
Location: Bevaix
Posts: 5

2001 Defender 90 2.5 TD Tomb Raider LE Bonatti Grey

Thanks, I’m very basic and I would appreciate if you can specify more which cable of the dash goes with which cable of the speedo healer, thanks a lot!

12th Dec 2024 3:01pm

jonny

Member Since: 10 Mar 2013
Location: North Wilts
Posts: 154

I would imagine that your speedo healer has 4 wires : positive, negative power feeds, a wire that goes 'in' for the speedo input, and one that comes 'out' for the altered speedo signal.

you need to connect the 'in' wire to the 'speedo' side of the yellow/pink wire, the 'out' to the ecu side of the same wire.

I would probably suggest taking it back to your mechanic and getting them to change it for you...

12th Dec 2024 3:05pm

Hazza

Member Since: 10 Jan 2011
Location: North Yorkshire / Leeds
Posts: 218

Harry.O wrote:
The red cable on the Speedohealer needs an ignition live, the black cable needs an earth. I cut the yellow/white ECU wire coming from terminal B13 on the black ECU plug, connected the white wire to the speedo gauge end and the green wire to the ECU end.

This should be the information you need.

The Speedo effectively doubles the pulse count coming from the Speedo transducer on the transfer box. Speedo transducer produces 4000 pulses per mile, Speedo then doubles that to 8000 pulses per mile which the ECU needs to see within a certain range depending on speed in order to use the cruise control. 1990 Defender 110 200TDI Camper - now converted to Td5 power

12th Dec 2024 3:11pm

Pepsyseventy

Member Since: 12 Dec 2024
Location: Bevaix
Posts: 5

jonny wrote:
I would imagine that your speedo healer has 4 wires : positive, negative power feeds, a wire that goes 'in' for the speedo input, and one that comes 'out' for the altered speedo signal.

you need to connect the 'in' wire to the 'speedo' side of the yellow/pink wire, the 'out' to the ecu side of the same wire.

I would probably suggest taking it back to your mechanic and getting them to change it for you...

Ok top!! thanks

13th Dec 2024 6:56am

Pepsyseventy

Member Since: 12 Dec 2024
Location: Bevaix
Posts: 5

Thanks all I will try to fix it!!

13th Dec 2024 7:00am

jst

Member Since: 14 Jan 2008
Location: Taunton
Posts: 8049

2011 Defender 110 Puma 2.4 USW Stornoway Grey

jonny wrote:
The TD5 ECU expects a certain ratio of revs to road speed for cruise control to engage, which is based on a 1.4 transfer box.

If you put a 1.2 transfer box in, the ratio changes which means CC won't engage, as the ECU thinks there's something wrong.

The solution is either to fit a speedo healer between the back of the speedo and the ECU to 'fool' the ECU, or to adjust the ratio within the ECU itself via nanocom or similar..

Great explanation, thank you. Cheers

James
110 2012 XS Utility
130 2011 M57 bespoke Camper
90 2010 Hardtop
90 M57 1988 Hardtop

13th Dec 2024 8:17am

TexasRover

Member Since: 24 Nov 2022
Location: Paris
Posts: 1078

2002 Defender 110 Td5 DCPU Chawton White

jonny wrote:
The TD5 ECU expects a certain ratio of revs to road speed for cruise control to engage, which is based on a 1.4 transfer box.

If you put a 1.2 transfer box in, the ratio changes which means CC won't engage, as the ECU thinks there's something wrong.

The solution is either to fit a speedo healer between the back of the speedo and the ECU to 'fool' the ECU, or to adjust the ratio within the ECU itself via nanocom or similar..

Quick question: I you fit an overdrive, I suppose that relationship between expected RPM for MPH will also be messed up and so the solution would be to fit a speedohealer (or Nanocom correction) tuned for OD engaged since that would be to most used setting for Cruise Control to be operated?

13th Dec 2024 10:54am

Hazza

Member Since: 10 Jan 2011
Location: North Yorkshire / Leeds
Posts: 218

Yes that would work - I'd imagine that with some basic wiring you could only have the Speedohealer switched on when the overdrive is engaged, so you'd be able to use cruise control both with and without overdrive engaged.
There are some cheap Speedohealer alternatives available on eBay too:

Click image to enlarge 1990 Defender 110 200TDI Camper - now converted to Td5 power

13th Dec 2024 11:14am

Harry.O

Member Since: 25 Jul 2014
Location: Warwickshire
Posts: 715

jst wrote:
Just for my knowledge.

Speedo healer but not used to adjust the speedo. So what role is it used in here ? Presumably a 1.2box gives wrong output speed to a cruise unit and this adjist it?

That's correct, or in my case, a v8 5th gear ratio fitted to the recon gearbox which was sending pulse signals outside of the parameters that the ECU liked. CC would engage then disengage after 2 or 3 seconds. 6 years later and the little Speedohealer is still working perfectly, interestingly it has never needed resetting since installation, despite being left for months with a totally dead vehicle battery

2005 Td5 110 Hardtop
1989 300Tdi 90 Soft top
1992 200Tdi 90 Truck cab with Land Cruiser axles

13th Dec 2024 7:58pm

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