Jump to content

Td5 Cruise Control


Recommended Posts

I have read that the Td5 ECU has built in Cruise Control functionality and reading around various forums it doesn't look too complicated to wire and activate.

One complication seems to be that the unit may not function ( or function correctly) if an overdrive is fitted, potentially because the revs are lower and fall below the lowest threshold permitted.

So my questions are:

Does anyone know what the lower rev limit is for cruise control to be able to be engaged?

And....

If the ECU is programmed with a Discover map will it operate at lower revs?

(I'm wondering if the permissible activation limit is lower because of the 1.2 ratio transfer box.)

And finally... Can the lower limit be amended to accommodate an overdrive?

Thanks in advance.

Neil

Link to post
Share on other sites
  • 4 months later...

Ok... I wired in the cruise control and it works..... Except in 5th gear with overdrive engaged....

So I can cruise in 4th or 5th without overdrive no problem and use CC in 4th with Overdrive engaged.....

But as soon as Overdrive is engaged and in 5th it will not work...

These guys claime to have a device that changes the pulses without affecting the speedo settings...

http://nakatanenga-tours.de/shop/article_TA%25201000/Angleichadapter-für-elektr.-Tachometer-_-Wegstreckenzähler.html?sessid=5oho9g1mBMlk7hTOCJXmBCNLiWmbPXkv8UeqS6KwHgnD5np1aarJWSL417HukmUT&shop_param=cid%3D24%26aid%3DTA%25201000%26

Anyone tested anything like this?

Link found in this thread...

http://www.defender2.net/forum/topic2281-15.html

Any suggestions from anyone on here? Would be a shame to have to spend loads of money on a gadget unless its the only way....

So far its been cheap....

Neil

Link to post
Share on other sites

Ok.. An evening of reading suggests I will indeed need to reduce the pulse rate...

Bitten the bullet and gone for one of these...
http://www.bikersdiscountstore.co.uk/speedo-healer-pl-19.php

Someone on another forum has this in line and claims it's worked for 6 months with his overdrive....


Fingers crossed...

I'll report back when installed.

Link to post
Share on other sites

I presume the way the box functions is just to persuade the vehicle it's going slower than it actually is? So the speedo will also read low?

I guess you could install the box, then re-program the speedo to read correctly or just accept that the speedo always reads low?

Si

Link to post
Share on other sites

It is my understanding that the speedo feeds the ECU, therefore the change in signal does not affect the Speedo at all....

I believe black terminal Pin 13 is the feed from speedo to ECU. The pulse feed to this pin needs to "slow" down to bring them back into line with what the ECU is expecting for 5th gear versus engine RPM.

If I understand it correctly, the ECU knows the RPM and expects a maximum road speed for the RPM... With bigger tyres and overdrive the ratio of RPM to speedo pulses goes outside Land Rover parameters and the Cruise Control will not engage.

Hopefully I can reduce these pulses by the respective amount and fool the ECU into engaging in 5th with Overdrive.

This may sacrifice being able to engage at lower road speeds, but that shouldn't matter to me as I want CC at 50 MPH and above really...

Neil

Edit: Ashcroft gear calculator suggests changes of tyres and introduction of Overdrive has resulted in a 19.4% lowering or RPM when in 5th and O/D engaged.....

Edited by V8 Freak
Additional information
Link to post
Share on other sites
  • 2 weeks later...

Well the Speedohealer arrived.....

It's tiny !!

It took approx. 20 minutes to install.

I cut the feed to pin 13 and connected the little unit in line. I used an ignition switched power feed and ran a separate earth.

Popped the ignition on and reading the instructions had it programmed up within 5 minutes.

I set it to minus 20% although I could have put in the -19.4% calculated.

Then the test drive... Bingo... 5th and overdrive and cruise control.....

IT WORKS....

This may be something someone clever like Mr Cwazy Wabbit can replicate much cheaper then the commercial units.

The unit I bought is totally waterproof and engineered for motorbike use.

A simpler unit probably set between -15% and -20% that's not set in resin may be available elsewhere on the market or could be made by someone with the expertise.

In conclusion.... You can have overdrive and cruise control in a TD5 Defender.....

Neil

Link to post
Share on other sites

Quick question Neil, what year is your Defender? I've been meaning to do this (cruise control) to my early Range Rover, having fitted a late cruise control steering wheel, but from what I've read I'll need to get a later ECU as the '00 one I'm running won't have cruise programmed. I'm basically wishing that you'll tell me I'm wrong. Oh and on a side note, which overdrive are you running?

Link to post
Share on other sites

Not sure how I missed this thread :blink:

Looks interesting, I'd be interested to test one of those boxes. I wonder how much of a delay there is between an input frequency change and an output frequency change?

Does the ECU also use the speedo pulse for anything to do with the engine map? If so could this cause a problem?

I guess it is just a little microcontroller lurking inside the box.

Link to post
Share on other sites
Quick question Neil, what year is your Defender? I've been meaning to do this (cruise control) to my early Range Rover, having fitted a late cruise control steering wheel, but from what I've read I'll need to get a later ECU as the '00 one I'm running won't have cruise programmed. I'm basically wishing that you'll tell me I'm wrong. Oh and on a side note, which overdrive are you running?

It's a 53 plate, so the later programmable ECU.

I'm no expert but I think you should be able to install newer ECU with the right maps for your truck using something like an appropriate Faultmate device or similar. I'm sure a grown up will be along at some point to advise if my understanding is correct or not....

I'm using the Roverdrive (Or Global Roverdrive as it's now called) which seems pretty robust so far. WIll see how it goes but 5000 miles in it's solid and reliable and used every day.

Link to post
Share on other sites
Not sure how I missed this thread :blink:Looks interesting, I'd be interested to test one of those boxes. I wonder how much of a delay there is between an input frequency change and an output frequency change?Does the ECU also use the speedo pulse for anything to do with the engine map? If so could this cause a problem?I guess it is just a little microcontroller lurking inside the box.

I'm happy to come down one day and let you have a prod Barry....

I my reading up on the topic I could find no evidence to suggest that anyone believed there was an interaction of the speedo input other than a parameter for the Cruise Control.

As far as I can tell from the seat of the pants assessment, the vehicle is performing just the same. I keep MPG records so will see how that looks at the next fill-up.

Neil

Link to post
Share on other sites
  • 6 months later...

Not sure how I missed this one either - I've just been posting in another thread about this issue. I have a cruise control fitted already but planned to fit a 1.2 transfer box - and found the net full of people saying it won't work.

Interesting that yours would work with the 1.2 (if I read it right) - but for the same reason - not with the overdrive.

Tonight I had a play with the 'tyre co-efficient' setting on the Nanocom - which enabled me to knock speed off from the ECU by reducing the figure and without altering the speedo reading.

When I get the transfer box and fitted in I'll report back with the result.

Link to post
Share on other sites
  • 9 months later...

@Anderzander,

Did you ever install the new transfer box and get the CC to work with the Nanocom setting? As far as I can read on other posts the setting in the Nanocom only changes the Nanocom displayed speed, it does not change the ECU reading. (I guess it's a simple formula on the Nanocom applied to the reading from the ECU when it shows it on the screen - basically a conversion)

@V8 Freak,

Reading your comments I would have a question: are there two wires from the Transfer box sender? One that goes to the ECU and another one that goes to the Speedometer?

I am asking because if there is only one and the Speedometer feeds from the ECU then you will affect both when changing the ECU. This will result in lower than reality speed value indicated on the Speedometer and a possible MOT failure.

Thank you!

Link to post
Share on other sites

The speed feed for the ECU is taken from the speedometer head unit. The speedo sender in the transfer box is directly connected to the speedometer head unit which then IIRC doubles the frequency and feeds it to the ECU.

Link to post
Share on other sites
  • 5 years later...

Hi! i have a question to @V8 Freak !

i have the same problem but from a higher ratio 5th  in my new Ashcroft gearbox, on a Defender Td5.

I already bough the Speedohealer unit but i need a wiring kit.

i have only the  unit. There are a lot of different cables available and i don't know wich one to order. 

FURTHERMORE, is there anything to change in the wiring?
Thanks for your help!! 

 

Link to post
Share on other sites

I seem to remember buying a generic loom with it and then wiring it in. Not too many wires involved. Need break in the feed from speedo to ECU (Pin 13 I think) and the Cruise wiring isn't too bad.

Link to post
Share on other sites
On 4/15/2013 at 9:19 AM, Shackleton said:

 from what I've read I'll need to get a later ECU as the '00 one I'm running won't have cruise programmed. 

Shackleton

So you are running a p38 pre 2000. Is it Gems or Thor? Either or should be able to be programmed for the Cruise Control. but think it is more than just an ECU as the system has vacuum activated bellows and other gubbins to hold the throttle cable at the selected speed.

L322's I think are drive by wire so can be sorted electronically but the P38's have a throttle cable.

Link to post
Share on other sites
On 2/3/2020 at 9:04 PM, jonnymarzo said:

Hi! i have a question to @V8 Freak !

i have the same problem but from a higher ratio 5th  in my new Ashcroft gearbox, on a Defender Td5.

I already bough the Speedohealer unit but i need a wiring kit.

i have only the  unit. There are a lot of different cables available and i don't know wich one to order. 

FURTHERMORE, is there anything to change in the wiring?
Thanks for your help!! 

 

Did you Speedohealer come with about a metre of wire and a plug a few inches from the box? If so I can dig out the wiring diagram from when I fitted mine (same principal - TD5 with a v8 5th gear ratio)

Link to post
Share on other sites
  • 2 weeks later...
45 minutes ago, Shackleton said:

Hi Simon, no I have a Td5 in my RRC. Thanks though :)

That just makes things very confusing. 

I would agree that the cruise control is built into the ECU I know this because I have has the engine light come on while I have been driving and this has prevented me from any input with the throttle pedal however by chance I did notice that I could control the speed with the cruise control and even increase it.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy