Hi,
Had my fattie now for about 3 weeks, I have noticed that on cruise control at any speed the engine is hunting slightly, perhaps once per second or so a minute bit of acceleration followed by slowing down. The speed doesnt vary but you can see it in the rev counter (just). It can also be seen in the instantaneous fuel consumption readings jumping up and down in time with the effect.It does effect the average MPG, at 70mph on cruise 29.5 mpg, without cruise 34.6.

Are there any adjustments that can be made? I have the GAP tool and have expeience of instrumentaion and control i.e. PID loops etc or is this lot hidden away out of reach?

Any thoughts gentlemen? BMW i3 Electric Car
2012 Full Fat RR 4.4 TDV8 (now gone)
2006 VW Touareg 3.0 TDi V6

if it hunts around 80mph as well then a autobox software update is required

I'll give it a go, is it very subtle as per my description? Can I see what version of software is in the gearbox? BMW i3 Electric Car
2012 Full Fat RR 4.4 TDV8 (now gone)
2006 VW Touareg 3.0 TDi V6

I understand that it is cured by a PCM s/w update. Mine does the same and is at least 2 s/w versions behind the current level. I forgot to have the update done when the passenger airbag recall was done very recently.

I've got a feeling mine does this too - I thought I was imagining things, but the symptoms described match what mine does exactly.

Which is the PCM and is that available from GAP? 2010 4.4 TDV8 Vogue SE

PCM is power (engine) control module.
Today I emailed Gap asking if the IIDTool can load later PCM s/w so suspect that they will have answered by tomorrow morning my time.

I can feel the change in pressure on my back against the seat as power fluctuates.

Interesting...and just to be different, I don't detect any such issues in my 5.0SC, seems to hold rock steady except around other traffic when it constantly slows down. Mike - MPx

2017 5.0 V8 Supercharged SVAutobigraphy Dynamic SVO Palette Grey (2021-...)
2012 5.0 V8 Supercharged Autoboigraphy Orkney Grey (2017-2021)
2007 4.2 V8 Supercharged Vogue SE Tonga Green (2012-2017)
2002 4.4 V8 Vogue Bonnatti Grey (2008-2012)

Patrick at Gap has advised that loading later version of the 4.4 TDV8 PCM s/w is possible using the IIDTool but that the person who handles the s/w update requests wont be back at work for another 2 weeks.

Wow that’s brilliant news and I do have the tool so I’ll hang on. BMW i3 Electric Car
2012 Full Fat RR 4.4 TDV8 (now gone)
2006 VW Touareg 3.0 TDi V6

MPx wrote:

Interesting...and just to be different, I don't detect any such issues in my 5.0SC, seems to hold rock steady except around other traffic when it constantly slows down.

AJGalaxy2012 wrote:

Wow that’s brilliant news and I do have the tool so I’ll hang on.

£25 i think..

stan wrote:

adaptive cruise control???????

Is the process straight forward to update it? I dont want to trash old fatty. BMW i3 Electric Car
2012 Full Fat RR 4.4 TDV8 (now gone)
2006 VW Touareg 3.0 TDi V6

Start with a fully charged battery and a decent capacity charger attached as your don't want the battery to go flat during the process.