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Booted the beast for a quick overtake yesterday and it ran up to 4,000 (ish) revs and just stayed there. Engine control module clearly holding it back despite foot on the floor waiting for the gearbox to get its act together and change. Lifted foot a bit and it changed gear OK. Possibly a touch harsh but it changed.

Tried couple more times and same thing. Won't go past 4,000 rpm whilst waiting for a gear change. Whether drop down for overtake or change up when driving. Changes just fine in normal amble mode. Usually between 2,000 - 3,000 depending on slope.
Pretty much same in sport mode.
Is this just a matter of the adaptive settings needing to be re-set or something more serious. I'm going to lift it up later and check the gearbox oil level despite no sign of leaks.
Sticking caliper to fix first though.

Car has been on short run duties all summer which can't be good. Hence sticky caliper.

Clive

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defo worth checking the fluid level

Is it a diesel?

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If its a petrol, at wide open it shouldnt be trying to shift until at least 5k.

So i would actually suggest the opposite is the problem, the gearbox isnt shifting because the engine hasnt reached the shift point yet... Something on the engine side is stopping the RPM climbing any higher.

Lifting your foot will have lowered the shift point and so it changed gear.

Will it rev past 4k in neutral? Any fault codes on the ECU?

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Aragorn wrote:

If its a petrol, at wide open it shouldnt be trying to shift until at least 5k.

So i would actually suggest the opposite is the problem, the gearbox isnt shifting because the engine hasnt reached the shift point yet... Something on the engine side is stopping the RPM climbing any higher.

Lifting your foot will have lowered the shift point and so it changed gear.

Will it rev past 4k in neutral? Any fault codes on the ECU?

Agree totally. Shift points are set by a combination of TPS and MAF sensor readings but if it isn't revving beyond 4,000 rpm, then that is your problem.

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Aragon

Petrol V8 4.0 year 2000 so Motronic nor GEMs.

No fault codes showing on Nanocom.

Revs just fine in neutral. Far as I can recall it has in the past happily spun past 5,000 revs before changing up but I just don't drive like that. Down here aggressive driving just gets you to the next queue a bit quicker.

Wondering if it's a kick down issue. Does the car need to be in the kick down range to go past normal change points?

Going under to check fluid level in a couple of minutes.

Clive

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Does it kick down when you floor it at 2,000 rpm? On mine it will change up at around 4,000 rpm unless it is in Sport mode then it will rev to the red line before changing. In Sport it also kicks down more readily.

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Fluid levels OK, drip then intermittent stream.

I'll check the kick down thing next time I go out, probably tomorrow.

Thanks.

Clive

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Made time for half an hours worth of Italian Tune-up which seems to have bought things back more or less under control.

Slightly scary as Crowborough is not only at No 1 on the list of roads to do for the "Driving with Eyes Wide Shut Club" but also the newly formed "20 is Plenty Everywhere Fraternity" with the executive committees clearly having a joint run this afternoon to confirm things. Not ideal environment for booting a P38.

The beast was very unhappy about kicking down the first couple of tries but after the fourth time of asking it swept happily up to 5,000 before changing. Ordinary booting had a few stumbles initially around the 4,000 rpm ish but it would push through. After half a dozen tries it seems pretty much back to what it was. Still seems to be a bit iffy on letting go of lock up and not as spritely above 70 as I think it used to be.

All in all it seems that the adaptive set-up in the gear change control had gotten its knickers firmly twisted and gone into Great-Grandad mode.

Clive

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TBH it still sounds more enginey to me... especially since your suggesting it felt stumbly around 4k then eventually pushed thru.

Bad MAF perhaps? When they get old they start underreading, which has the biggest impact at high engine speeds

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After the best part of 150 miles today at "normal for Sussex" speeds the beast is running much nicer. Changes all come when they should and throttle response is decent. No booting today though. Not with Teddy the Malinois riding in the back. Pissing off a retired Police dog seems less than wise.

Hadn't realised how much things had dropped off over a summer of (mostly) shopping runs of 4 miles each way (ish). Decent bit of motorway run due on Saturday so we will see how he reacts to that.

For now I'm going with the adaptive systems getting out of kilter.

Clive

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On the Thor, the gearbox has adaptive values as well as the engine, so it may well be that it has got offended with doing lots of short journeys.

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yes short runs for a contiguous time dose not help things with rovers , i have always said that they would rather do a 1000 km run that 100km around town. they do need a good run from time to time .

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Managed another 100 or so miles today with a reasonable amount of motorways and fast road. Gearbox adaptives seem to have gotten their act together but the beast is still reluctant to deliver power above about 4,000 rpm and no proper lockdown surge above 3,000 (ish). I did manage to get him delivering power past 4,500 a time or two tho'.

Feels a lot like he's not getting full throttle. Did the obvious check and verified full movement on the actuator. Adjusted up the cable as far as it would go but there is still 1/8" gap between the cable sector and the actuator proper. Never touched cable since I bought the car so adjustment probably isn't the issue. New cable in stock.

Only fault Nanocom picked up when we got home is :
PD172 = Mixture adaptation Failure FRA
Bank 1 Drive Cycle 3
Occurred 4 times, signal too high, intermittent and not present
All the values look sensible at idle.

I'm thinking Throttle Position Sensor issues rather than MAF. Is there a way of cleaning the innards?

Chucked a bottle of injector cleaner in on the off chance. Can't hurt. Hopefully I can fit in bit more running tomorrow.

Spending £17,000 on an Audi A6 Allroad for the official unofficial kid sister ought to be worth a few brownie points! Which I desperately need as she is here for month whilst her bathroom is rebuilt!

Clive

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I always remember what Dave Ashcroft said to me: "if the gear changes are not right, change the MAF".

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Given you have mixture codes, why would you think its related to the TPS?

As i said a few posts ago, when bosch MAF's fail, they tend to under read (often worse at high load), and will often cause mixture codes. They do so in a way that the ECU doesnt really notice its wrong, but because it doesnt reflect the actual airflow the fuelling ends up wrong.

Unplug the MAF and see if it drives any better.

If the MAF is "working" but providing incorrect data, the engine wont run properly.
If the MAF is not working at all, the ECU will ignore it and use backup parameters, which are usually close enough.

Thus if it runs better without the MAF you have a reasonable indicator that its at fault. Its not 100% but certainly a good indicator.

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Reason for suspecting the TPS is that the car feels as if it's not reading about the last third of throttle travel. Drives normal up to around half and a bit but the ECU doesn't seem to be seeing anything beyond. Feels just like a carburetted engine with restricted fuel flow so it can't keep up with the engine demands when you want high power and high revs. Something I've had deal of experience with on motorcycles.

I expected that MAF issues would throw up all sorts of continuous codes rather than a fairly rare intermittent.

Next step is to try driving with the MAF unplugged.

Clive

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Thing is, the TPS doesnt do a huge amount, its used for idle control, transient fuelling/accell enrichment and as a backup for when other sensors have failed.

MAF is the primary input for fuelling on Motronic. There is essentially direct lookup table that pulls the MAF value and turns it into an injector duty cycle. Everything else then feeds into what the MAF is saying as corrections/adjustments/trims.

Sometimes you'll get a code for sure, but they are well known to have this silent failure method.

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Well that was "interesting". Went the long and expensive way round but finally sorted.

Turned out to be throttle cable adjustment being way out. As it has been in all 11 years I've owned the car. It always seemed to run OK so I never bothered to check the setting it arrived with, basically 3/16" free play with the adjuster close to the end of its travel. With it that far off book I guess the MAF and TPS, which according to RAVE has an important part to play in setting fuelling all through the range, were barely on the same page and drift over the years finally put them at odds.

After ordering a MAF from Land Rover Direct on the 7 th, because the Island 4x4 site, wasn't working for me, I decided to try things with the throttle adjusted up as far as it would go. Still 1/8" play but I was able to get a kick-down with full blooded stamp on the accelerator. As I had a new cable in stock and the one fitted was out of adjuster travel I decided to change the cable.

Bad idea!

2 days of struggle swearing and trying various things finally got the old one out. If I ever pull another one out I shall immediately cut the inner cable and chisel off the end of the rubber sleeved plastic thingy inside the car. With the knob on the end gone a few swift taps with the special offset drift I welded up for the job pushed the thing out far enough to grab on etc outside easy as could be. Given how impossibly stubborn mine was initially I expected to find the support tube in the body corroded to hell and gone. In actuality it was perfectly smooth. I reckon the difficulty of removal is due to the knob on the end of the plastic bit swelling the rubber ridge sitting on the inner end of the bulkhead support so much that no power on earth will pull it through.

New cable went in easily. I used red rubber grease rather than the RAVE approved liquid soap. Persuading the little plastic bung to go into the hole in the accelerator cable took another half day of braille manipulation. If you don't get it right first time it's fatally easy to spread one of the prongs a little bit. With predictable results. I found it best to tape the other end of the cable up to compress the boot to its minimum length so there was some excess cable inside permitting free movement of the plastic bung. Wooden block under the accelerator pedal held it out of the way at bottom of its travel. No way that I found to stop the pedal going up the left sleeve of my overalls every time I moved.

New cable had just enough adjustment to get the gap between cable selector and actuator down to about 1 mm. Leading me to think it was a pattern cable.

Bonnet shut, interior plastic re-fitted, tidying up nearly done when the penny dropped. RAVE shows the cable bracket running straight up and down. Mine was at an angle leaning towards the throttle actuators. Surely the bracket holes aren't slotted. Diving under the bonnet again and making with a spanner proved they were slotted. Setting the bracket vertical restored the cable adjustment to something sensible with the RAVE specified zero gap between cable and acutator.

Which I could have done in the first place if I'd gone back to first principles and verified all the set up rather than assuming "it was OK, now something has gone wrong". Considering thats the first thing I do with someone else's problem its distinctly hoist with my own petard. Sigh.

Quick test run shows car is now much more lively than it ever was and the gearbox much more responsive to the throttle. It always seemed to drive decently before but very much non sporting. As I expected from a softly tuned V8 in 2 tons of permanent four wheel drive car with the aerodynamics of a shed. Seemingly effortless 80 mph motorway cruise was clearly deceptive.

Just to make a bad weekend and start to this week worse the poxy SRS light has come on. Double checked any connections that might have gotten disturbed to no avail so hopefully it's an intermittent issue returning after 5 years.

Foam in the heater duct joints had gone so I used some self adhesive ribbed door/window sealer got from LiDL a year or three back 'cos it might be handy. Just the job. Before fitting I went round the ends of the duct with duct tape leaving about half the width upstanding. 8 snipe cuts, two at each end of the corners, let me fold the tape down over the draught sealer so things didn't get caught up on the edges of the other parts of the duct. The duct slipped in so easily that I had to look three times to confirm it was in.

Clive

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Good news about the shifting! Maybe it’s something we all need to look at on our 25 year old vehicles.