D4 Cruise Control

[Disco4SE]

Hi all,
I know that there have been discussions on this before.......but lately I have noticed that the set speed on my D4 on cruise control is fluctuating even more.
It slows to up to 6Kph below set speed and raises up to 4Kph above set speed, up and down hills. Given that it is the 3.0Lt and vary rarely changes down a gear, this seems strange.
It only ever used to fluctuate + or - 2Kph.
I had another AULRO member in my vehicle last week. He has the D4 2.7Lt and mentioned that his hardly ever alters from the set speed.
Any clues????????
Cheers, Craig

[Jesse B]

Craig - interesting that you've raised this, as just the other day I noticed that I'd crept up to 4 kph over over the set speed going down a hill, and this was unusual as mine has kept pretty much to the +/- 2 kph variance since new. Not a particularly massive hill, and one that I regularly drive - so nothing new there. Have not noticed any significant drop off on the down side yet. I know Graeme's bus was showing more variation early on - be interested to see what his situation is now.

[Graeme]

Mine hasn't changed and thus still can't be trusted in hilly terrain. I find quite annoying when lots of other vehicles can keep a constant speed and I am forever adjusting mine. I cancel at 4 kph over because of the likelihood of going a lot higher. Cancelling totally cuts fuel whereas overrun does not.

[ADMIRAL]

I have never used a cruise control that holds the set speed on a reasonable descent. A slight incline yes, but not a descent sized hill. I know a lot of the heavier truck transmissions, and even some of the 'Allisons' fitted to the big Chevy Silverado's, have a sophisticated enough setup to hold the set speed, even with a load on the back ( like a caravan ) on any downhill slope.

The D4 is no different to the others ( in my experience ). I think your expectation is a little high.

[games1]

It seems that the D4 allows the slight de-acceleration of approx 4km while going uphill which actually avoids the abrupt changedown I have experienced with previous vehicles. Its appears to be more intuitive in uphill with the downhill being related to momentum more than acceleration.

[Disco4SE]

Sounds like it is a common fault with the D4. My D3 was always within 1...maybe 2Kph up and down hills.
Discojools commented that his D3 was all over the place, whereas his D4 cruise is great.
Does anyone know whether this fluctaution can be adjusted?
Cheers, Craig

[Celtoid]

My D4 3.0L has always been shocking on cruise control on anything but the most level of roads. I made comment on another thread that it was by far the worst out of all the cars I've owned.

With the 'smarts' the car has, the 6 speed box and the 600Nms of torque....there really isn't any excuse.

[OzAd4x4]

My 2.7 D4 is a shocker on cruise also. I appreciate the fact that the 6 speed doesn't kick down aggressively to maintain speed however more often than not it shouldn't need to anyway as it has enough grunt to maintain the speed as proved by manually (without cruise set) attacking the same incline.

Mine drops approximately 6kph before it seems to realise it's no longer doing the speed selected and apply more throttle, or then kick down because it has slowed so much that it is now out of the torque band.... quite frustrating really. My manual diesel Jeep was great in comparison if not a little aggressive with it's response.

[101RRS]

On the flat and when the engine loads up a bit up hills my RRS is able to hold speed very well - normally within 1kph but going downhill is a different matter. The car runs on very easily suppose is is reasonable aerodynamics and its considerable weight but it also does this on cruise control - going downhill I have been up to 20kph over the speed set.

The cruise control is obviously a very basic system simply opening and closing the throttle - I would have thought that given the price of the car the system would have been a bit smarter - maybe even feathering the brakes to minimise over run.

Garry

[Jesse B]

The car runs on very easily suppose is is reasonable aerodynamics and its considerable weight but it also does this on cruise control - going downhill I have been up to 20kph over the speed set.

Garry

Strewth - I'm starting to think mine is one of the better ones, given this kind of scenario! :eek: What interests me in your situation, Craig, and to a lesser extent in mine, is that the variance appears to be getting worse. Others seem to be saying theirs have always been lousy. I wonder what might cause this? Could it be as simple as everything loosening up, spinning more freely etc - though really this should be irrelevant, shouldn't it?

[Discophil]

My 2.7 TDV6 D3 tends to hold ok and drop down when required. What i find annoying is that when i try to resume the cruise control, it seems to think for about 5 secs before it realises it needs to accelerate to maintain its previous speed setting.:confused:

[Disco4SE]

I have had the D4 stuck on its belly a few times. Whether this has moved or altered a sensor underneath.........I don't know.
You would think that with all the electronics on the vehicle, it would be a matter of plugging it into a diagnostic machine and making the appropriate adjustments.
Keen to hear a fix. :confused:
Cheers, Craig

[discojools]

As mentioned by Craig my 2.7 D4's cruise control works so much better (actually excellent) than my 05 D3. My 08 TDV8 RRS is somewhere between the two. However I have noticed that all 3 do run away down hills and it's better to switch the cruise off which I don't understand as you would think that the throttle would be completely off when the speed is over the speed set. Craig, did you tell ULR about your problem last week when it was serviced?

[Disco4SE]

As mentioned by Craig my 2.7 D4's cruise control works so much better (actually excellent) than my 05 D3. My 08 TDV8 RRS is somewhere between the two. However I have noticed that all 3 do run away down hills and it's better to switch the cruise off which I don't understand as you would think that the throttle would be completely off when the speed is over the speed set. Craig, did you tell ULR about your problem last week when it was serviced?
Jools, would you believe I forgot to mention it ;)
I have to go to town tomorrow, so I'll drop in there and sus them out.
Cheers, Craig

[Graeme]

However I have noticed that all 3 do run away down hills and it's better to switch the cruise off which I don't understand as you would think that the throttle would be completely off when the speed is over the speed set.
The instantaneous fuel consumption display on my 3.0 shows that fuel is still being consumed even when grossly overspeed, but shows zero if CC is cancelled and the retardation effect is immediate. It may be programmed this way to attempt a smoother re-application of power once no longer overspeed, but its no excuse. The slowing uphill is easily overcome by upping the set-speed by a notch or 2 (then reduced again before the crest) so its not due to lack of power.

[gt_convert]

bbb

[101RRS]

The instantaneous fuel consumption display on my 3.0 shows that fuel is still being consumed even when grossly overspeed,

As I slight diversion - does anyone know if there is a way to display instantaneous fuel consumption on the D3 system?

Garry

[Bushwanderer]

bbb

Hi gt,
Not an enviable start to the forum.

I suggest that you consider the posts more carefully before posting derogatory replies. It reflects more on you than the poster.

Best Wishes,
Peter

[gghaggis]

As I slight diversion - does anyone know if there is a way to display instantaneous fuel consumption on the D3 system?

Garry

Other than continually resetting the average fuel consumption, I don't think so.

Cheers,

Gordon

[101RRS]

Other than continually resetting the average fuel consumption, I don't think so.

Ok - thanks - I thought there might be some hidden setting that allows it to be selected - most other makes trip computers have had that option for years.

Cheers

Garry

[Disco4SE]

Dropped into ULR today. They couldn't tell me much other than to drop the vehicle off and they will have a look at it.
Spoke with MLR as well today. They suggested that there is no control on the downhill, in other words, the vehicle will not slow on a downhill slope on cruise, however it should maintain speed up a hill :confused:
With a bit of luck, someone will work out how to maintain the set cruise speed +/- 1Kph as it should be.
Cheers, Craig

[101RRS]

They suggested that there is no control on the downhill, in other words, the vehicle will not slow on a downhill slope on cruise,

I find that odd as the throttle should close when overspeeding and as certainly the torque converter should be locked the car should slow back to the set speed. Lower speeds might be different but at "cruising sppeds the torque converter should be locked. However with my RRS you have to ride the brakes to keep the speed in check on overrun.

Garry

[Celtoid]

I'm certain mine does slow down (or it appears to) when it overspeeds but it can be well over the speed limit when it does.

[jonesfam]

I have a scangauge 2 on my D3. This gives a fuel consumption update every 2 seconds & according to it fuel use drops to 0 when over-speeding down hill. If I set it to litres per hour it still uses a little fuel, I don't remember the figures.
Every other car with C/C I have owned mentions in the manual that C/C will not apply brakes & to be aware that the car may increase speed down hill, makes sense to me. If you are doing (or trying to do) 100kph at the top of a steep hill you will be speeding by the bottom if you don't use the brakes or drop a gear. Try it without C/C, you will still be speeding.
Also I have never heard of a C/C that uses the brakes though the gear box etc is pretty clever, you wonder why it doesn't drop a gear or 2 to slow you down a bit?
Jonesfam

[Duck's Guts]

I'm certain mine does slow down (or it appears to) when it overspeeds but it can be well over the speed limit when it does.

My D4 does the same.
Generally, CC maintains +- 2km/hr from the set speed, but this can vary as much as +-10km/hr at the crest or bottom of a hill in undulating topography.
Also, the CC does runaway down large hills.
Overall, given the fact that the speedo is inaccurate (displays 106 at a true/correct 100km/hr), I'm not suprised the CC also is inaccurate.


Also I have never heard of a C/C that uses the brakes though the gear box etc is pretty clever, you wonder why it doesn't drop a gear or 2 to slow you down a bit?
Jonesfam

My R51 Pathie's auto is particularly good at dropping gears to maintain the CC setting when travelling down hill. I wish the D4 did this...

[101RRS]

Overall, given the fact that the speedo is inaccurate (displays 106 at a true/correct 100km/hr)

That is not an inaccurate speedo - well within specs - must not read slow and can over read by up to 10%.

Garry

[Duck's Guts]

That is not an inaccurate speedo - well within specs - must not read slow and can over read by up to 10%.
Garry

Yes the speedo operation IS within specification....but that doesn't mean it is accurate.

[Graeme]

I'm very pleased to report that since my 3.0 D4 had some software updates applied yesterday, CC now works properly (IMO). Overrun now totally cuts fuel (as shown by the instantaneous consumption display), it only looses about 2kph uphill, it very quickly reduces power as hills are crested (I didn't have to cancel CC once in the 500 km trip home) and holding the speed decrease button causes CC to be suspended until the button is released whereupon the setspeed is set to the current speed. It is now very useful in quite hilly terrain - permagrin for CC at last!

[Disco4SE]

I'm very pleased to report that since my 3.0 D4 had some software updates applied yesterday
Was this done by a dealer Graeme. I had a service recently and they told me that I had the latest updates installed, yet my cruise is still all over the place????
Cheers, Craig

[Graeme]

Yes, done by MLR.

Edit: I suggest using the instaneous fuel consumption display on an over-run situation to gauge whether the latest software is installed or not. I tested it again this morning on flat road by holding the speed decrease button from 100 kph cruise and within a few seconds the consumption showed 0.0.

[SBD4]

It is now very useful in quite hilly terrain - permagrin for CC at last!

Graeme, good to see there is something available to sort this out! CC has been irritating me endlessly with the way it currently works - if I increase the CC speed by 6Kph as I start to go up a hill, I get to maintain the desired speed. Naturally I have to decrease it to the previous setting as we get to the crest. What a pain!

Does any one else find the 2 kph increments an inconvenience? It seems that you're travelling that little bit too fast or to slow when following another vehicle with cc set. Is there any setting or fix to allow 1 kph increments to CC setting?

[Graeme]

I ageee, its a pain as it seems that other brands of vehicles can maintain speed quite well. Next time I'm on the freeway (not soon AFAIK) I'll be trying sport mode and comand shift to see if CC maintains speed better. I don't mind dropping a few kph if no vehicle is behind but don't particularly like playing leap-frog.

[Robocop]

I haven't had any issues with my D4 cc but at my last service they did tell me there was no software upgrades, mine was up to date.

I'm gonna sound like my old man here but I did an Econ run on one of my trips back from Syd.. cc set about 4kph higher on speed limits (I've found I'm being constantly harassed at the speed limit, I assumed it read slow).. On the up hills I let it do it's thing, on the downs I knocked it into neutral & coasted (yes I know it's not best practice).. At times it would easily coast above 120, slow down on the next hill then press reset cc.

I noticed a huge difference on the inst fuel down hill (of course) with a marginal yet noticeable difference in fuel consumption.

All in all I'm happy with the cc, id like the option to auto change down on down hills but also to be able to turn it off. Or I'll just do it manually anyway.

On the coasting with cc on I did find it annoying as it coasted "too well", knowing there were speed traps on the down hills I had to dab the brakes..

Still the best car I've owned to date..

[SBD4]

Next time I'm on the freeway (not soon AFAIK) I'll be trying sport mode and comand shift to see if CC maintains speed better.

I'll be heading to the South Coast this week so I might give your suggestions a try. I'm sure I'll still need the s/w update.



I'm gonna sound like my old man here but I did an Econ run on one of my trips back from Syd..

..Still the best car I've owned to date..

I wouldn't worry about the old man bit robocop - I think it's a universal tendency. Just last week I embarked on the same mission, heading down the mountain to nth Ryde I averaged 6.2, on the way back 7.6 - 200km round trip, my best numbers ever! Very judicious with the accelerator and brake and extensive use of cc.

....and yep, definitely agree - best car I ever had too.

[outasight]

This is the worst cruise control I've ever had.

I'm sure there could be worse out there, but 4 brands prior have all been better at maintaining speed on up hills and all had 1 kph increments.

The downhill thing is probably a lot to do with the 2.5 ton, but as others have noted, the transmission could be utilised somewhat.

Health check service coming, so will also ask for this to be checked.

[Robocop]

I'm not understanding why it needs to be in increments of 1kph? All our speed limits are even numbers.... But I am that OCD type that can't have the speedo on an odd number.. I would have preferred a trip computer function like the time of arrival like I had on my SS..

[Disomania]

My Golf has a 1kph increments and holds speed up and down hill - it even changes gears (DSG) down to keep the speed at the set level.

My D4 will ALWAYS go 4kph over the set speed on resume, and if I tap the speed up, it will go 2kph over the speed then settle back down. up/down hills it mostly OK with it not dropping more than 2kph either way. Should be faster to react to speed fluctuations IMO.

And I'd like 1kph increments on it as it's a pain to get the speed correct. On the GPS and display signs when on the Hume in Victoria, my car reads 105 at a 'true' 100. I like to be at the speed limit not 1kph up/down. Being a little anal about it, I find it can take 3 or 4 goes to get the cruise on the odd number.

[Graeme]

The downhill thing is probably a lot to do with the 2.5 ton, but as others have noted, the transmission could be utilised somewhat.
The gbox will drop to 5th if in auto and the brakes are used on overrun, at freeway speeds anyway. I often set a new CC speed rather than resume to avoid having to be travelling at exactly the old CC speed and to have been doing so for at least a few seconds in order to prevent either significant acceleration or loss of speed.

My CCF has been adjusted so that the speedo is a maximum of 1 kph fast at 110 kph. I'm much happier to know that I'm travelling at the speed limit than continually having to verify with the GPS that I'm not really doing another 5 kph, especially when speed increases downhill where I will apply the brakes if speed is going to exceed 7 kph over the limit.

My ETA is shown on the el-cheapo Chinese GPS system. Its also one of the figures I can read without having to change to reading glasses.

[Robocop]

Are you certain Graeme? I've only 2 weeks ago on the HWY around Suttons Forrest had the cc set on 112, on one of the downhills I let it do it's thing, it coasted away not changing down or applying the brakes to 128kph. I'd rather it didn't apply the brakes anyway but I now know to keep an eye out.

[Graeme]

When the driver applies the brakes, not CC.

[SBD4]

The gbox will drop to 5th if in auto and the brakes are used on overrun, at freeway speeds anyway.

Yep, I agree. Though, it'd be nice if the CC would do that for you rather than you having to apply the brake thus cancelling CC. The Inlaws 15 year old E320 does this effectively. Obviously, on steeper slopes it would be unreasonable to expect any cruise control to to fully check runaway speed that way.

Graeme do you know if there is any CCF setting that would allow 1kph increments for CC speed setting?

[Graeme]

I haven't seen a CCF setting to allow 1 kph increments. If I catch a vehicle that's travelling slightly slower I'll increase my speed by 4kph until sufficiently past them then settle back to the speed limit rather than try to travel at their speed.

My CCF settings for my tyre size is set correctly (245/70-17) and the speedo algorithm selected is the one closest to no adjustment (IIRC 0%+2 kph) rather than the greatest adjustment (IIRC 5%+2 kph) previously. On level terrain with my CC set at 100 the speedo shows 100 and the GPS mostly shows 100 but sometimes 99. However my tyres when new were listed as 30.8" dia by Tirerack whereas the size has a nominal dia of 30.5", which probably accounts for my speedo not being 2kph optomistic. I'm happy doing 99/100 in a 100 zone with the speedo showing 100 or 109/110 in a 110 zone with the speedo showing 110 with CC set at 100 or 110 accordingly.

If changing CCF specs for non-standard tyre diameter then consideration might be given to correcting the CCF setting for the odometer. Faultmate has 2 tyre rolling diameter fields which I've found to be used to set the odometer - the Most Significant (1st) Byte and Least Significant Byte (2nd) such that when each is converted to hex to make a word of the rolling diameter then converted back to decimal, the number is the loaded rolling diameter in mm. I added 10 (mm) to the LSB value to account for my tyres' slightly greater radius than standard and the odometer has since agreed on several occasions with the freeway 5 km odometer checks whilst travelling in the left lane.

[outasight]

Watched everything very carefully on the Eastern Fwy & Eastlink today - all the way to Frankston.

Set at 104 kph and even on slight declines off bridges got 107 - 3 over is enough for a ticket. Dropped as low as 98 before regaining to 100 up the long incline under the Monash Fwy. Rediculous as cars catch you rapidly.

Set at 80 in the tunnel(quite a long reasonable downhill), not one gear dropped down at all, and applied the brakes as it was heading past 95 just a few hundred metres in.

The instantaneous fuel usage was at 0.0 on each down hill.

I tried gears myself to stop from exceeding 104kph. 4th was needed, 5th still allowed increased speed. 4th wasn't too harsh/high revving or noisy at 104.

Regards,

Les.

[Graeme]

Set at 80 in the tunnel(quite a long reasonable downhill), not one gear dropped down at all, and applied the brakes as it was heading past 95 just a few hundred metres in.
Mine drops whilst CC is not in use prior to touching the brakes with speed around 115 each time. Dropping to 5th didn't slow the vehicle and left me wondering if the change-down was to get more engine revs for more brake vacuum or for more engine braking.

[Redback]

I hate the CC on our D4, it will not sit at the speed you set it too, if I set it to 106kph (speedo is 6kph out) it then drops to 102, 103, it starts to increase and it will sit at 105 for ages, then go to 106 and on to , 107, 108, 109 then back to 103, 104, then 108, all this on a relatively flat road, it will eventually sit on 106 but only for a second then it's all over the place again:twisted:

Baz.

[Disco4SE]

Seems like everyone has the same problem.
Come on Landrover.........surely you have a patch for this??????

BTW: I have all the latest updates and my cruise does the same.

Cheers, Craig

[Graeme]

Come on Landrover.........surely you have a patch for this??????
I'm not holding my breath for a fix as it took the whole D3 model run and into the D4s before LR changed CC code to totally cut fuel on overrun, and probably only because every D4 driver could see that fuel was still being used by looking at the instantaneous fuel consumption display.

[Stuart02]

I'm not holding my breath for a fix as it took the whole D3 model run and into the D4s before LR changed CC code to totally cut fuel on overrun, and probably only because every D4 driver could see that fuel was still being used by looking at the instantaneous fuel consumption display.

I bet fuel use is exactly the same, just the display is now kidding you that the engine's not using fuel! Just like the classic temp gauge adjustment that Holden pulled to stop Kingswood owners worrying!

I think while the CC is tedious under the discussed conditions, its a sensitivity compromise that makes it surge much less on undulating secondary roads, and therefore usable in a much wider range of situations...

[Graeme]

I bet fuel use is exactly the same, just the display is now kidding you that the engine's not using fuel!Definitely not! Previously on downhill overruns the vehicle would race away yet now does not reach anything like the previous speeds on the same freeway hills. It now behaves the same as when CC was cancelled prior to the s/w update.

[Redback]

I bet fuel use is exactly the same, just the display is now kidding you that the engine's not using fuel! Just like the classic temp gauge adjustment that Holden pulled to stop Kingswood owners worrying!

I think while the CC is tedious under the discussed conditions, its a sensitivity compromise that makes it surge much less on undulating secondary roads, and therefore usable in a much wider range of situations...

I can't use my CC on undulating country roads, it's even worse in these terrains:twisted:

Baz.

[Tombie]

I'm happy to report mine works wonderfully :cool: always within 1-2 km of set speed.... And gets back to set quickly on a hill... (Will change down quickly and maintains momentum)

I think part of the issue is the digital speedo - it makes the pedantics see a 1-2km/h variation and get "anal"... The analogue version barely moves so in earlier models people never noticed...

Offroad tracks it all runs stable too, I went out and tested out the back areas here to check - although I wont drive loose surfaces on cruise...

[Graeme]

I wont drive loose surfaces on cruise...And miss out on all the fun?

I think you're right on target with the digital vs analogue speedo comment.

[Redback]

I'm happy to report mine works wonderfully :cool: always within 1-2 km of set speed.... And gets back to set quickly on a hill... (Will change down quickly and maintains momentum)

I think part of the issue is the digital speedo - it makes the pedantics see a 1-2km/h variation and get "anal"... The analogue version barely moves so in earlier models people never noticed...

Offroad tracks it all runs stable too, I went out and tested out the back areas here to check - although I wont drive loose surfaces on cruise...

No not in our case, I'm also comparing the D4 to the D2 and Nessies Amarok, I could put up with the variences in the D2, but when the difference is 4 to 6ks and at times up to 3 to 5 seconds to react, that's not pedantic, that's a pain in the arse.

Baz.

[NTB]

I also have a MY11 D4 SDV6.
I too find the Cruise Control operation poor. I have had Cruise Control in both Ford's and Holden's and they performed very well. The D4 looses alot of speed on a hills and I find this frustrating. Both the Analog and Digital drop.

NTB

[discowhite]

Im with tommie 100%
The cruise on my chipped oversized tyred 3.2ton D4 is excellent!
2klm under set and it reacts, gets about 4klm over depending on road, flat down hill etc.
Now if it's a really big hill I just knock it over to sport, still keeps the set speed about spot on.

Cheers Phil

[outasight]

Clearly there is some fundamental difference in Tombie & discowhite's experience vs the rest.

In my case it has nothing to do with being anal or speedos - the car just slows too much without reacting. The traffic catching you & the gentle right foot "help" proves that! Also you can literally feel it slowing & you would feel the reaction IF it occured. It doesn't.

Regards,

Les.

[discojools]

Have to say that my D4 2.7 cc is pretty good and holds on to speed on hills well.. It does run away a little down hills (despite showing 0lt/100) but a slight dab of the brakes and hit resume at the bottom is all it takes..Certainly alot better than my D3. My TDV8 Sport (now gone) also had good cc. Was slightly better down hills..maybe the extra 2 cylinders helped in that respect. Have a def 90 coming so won't be able to compare as that doesn't have cc!