Hi all,

Been away from the forum for a little while but, right when I really needed it most (sick parent transport, and now remaining parent care duties) the car has decided to have another fit..

Intermittently I'll feel a loss of power with accompanying black smoke and, often, limp mode will engage and I'll be forced to coast to a stop. Stopping and restarting clears the fault and the car will drive normally again - maybe for days, maybe for a couple of weeks, but eventually I'll pop up again; usually going up a long gradual hill (like the hills on the A605 by the A1).

The full code is "P023D-22 (6 Manifold absolute pressure - turbocharger/supercharger boost sensor A correlation - General signal failure signal amplitude >maximum", there are no other correlating codes.

Googling around the most common cause is (in order of "Why must you try to bankrupt me now, car!"):

Split intercooler hoses
Split intercooler
Split intake manifold(s)
Dead turbo

Not sure if you have this or not, but a list of L/R's possible causes may help.



Cheers
Col

Thanks Col!

I had looked at the list, but I hadn't really thought about the MAF sensors; I guess the correlation failure is either "more air is passing the MAF than the MAP sensor can account for" or "more pressure at the MAP sensor than the MAF can account for"..

I'm assuming that if it was a turbo actuator position fault, I'd have a correlating fault for that as well, which I don't - so I think I can rule that one out (although they did get stuck a couple of years ago, so I'll crawl under and give them a wiggle).

I swapped the MAP sensor between banks so it'll be interesting to see if the fault moves, and I think I can do the same with the MAF sensors after the next occurrence to see if the fault moves with those.

Rather hoping it's not turbo or intake manifolds.. Having now looked at the parts diagram I realise the intake manifolds are part of the rocker covers, I've never seen that before, but I know there's four more rubber hoses I need to check now (between the 'air duct' and intake manifolds). At least, I assume the parts that crack are the ones here - https://www.advancedfactors.co.uk/inlet-ma...1735-c.asp - and not LR004046? 2014 BMW 530d Touring, 2006 BMW 650i, 2018 Mini Cooper S

Hi,
My experience would suggest that you have a cracked inlet manifold, your symptoms exactly match what we had....driving up a hill would eventually cause the fault.

Check my video on youtube on how I found the crack:

https://www.youtube.com/watch?v=neTJs7nyc0...speravanti

Cheers for that! You know what's funny? I sat down this morning and had (another ) Google for the problem and had two videos open in my browser to sit down and watch after the morning meetings at work..

One was yours

I'll break out the soapy water .. been meaning to find the leak in my argon line on the TIG welder for ages so I can kill two birds with one stone  2014 BMW 530d Touring, 2006 BMW 650i, 2018 Mini Cooper S

iforland wrote:

https://www.youtube.com/watch?v=neTJs7nyc0...speravanti

I haven't had chance to pressure test the intake yet but did have a scout around yesterday with the engine cover off and noticed (in the daylight) that there's a sooty/oily stain on the drivers side around that post the heat shield bolts to (visible in your video) and I think I can see a crack in exactly the same location as yours..

Did you replace yourself or pay someone to do it? I've found videos describing the process on the TDV6 which looks long and involved but not 'complicated' exactly, but nobody doing it on the TDV8.. I'll give Avenger a call and make sure I'm sitting down when I ask the price and then decide whether I want to DIY! 2014 BMW 530d Touring, 2006 BMW 650i, 2018 Mini Cooper S

I've done both sides on my TDV8, if you are fairly good/confident with the spanners then its not too bad, space is a major issue and lots does have to come off including the injection pipes etc....I ignored the Land Rover workshop manual that stated you have to replace the metal injector pipes, they were expensive and I have had no issues in the years since I did the first one.

The actually inlet manifolds are fairly expensive....I did try using expoxy and some other products to fix, without luck. However since I did them I have become good at plastic welding bumpers and interior parts that are broken, so I'm wondering if they could be plastic welded in place.

Cheers - thanks for that

Yeah, the OE manifolds are incredibly expensive (£700 a side if memory serves) and aftermarket aren't much better (£400 or so); I had the same thought about plastic welding them when I saw what looks like the crack - it would certainly save a lot of bother if doable on the car! If they had to come off to be welded effectively (and you were paying for labour) then you might as well change them I reckon, but as a DIY option.. I'm tempted to give it a bash.

It's already f.. broken, can't break it any more!  2014 BMW 530d Touring, 2006 BMW 650i, 2018 Mini Cooper S

too true, I use a DREMEL VersaTip gas powered soldering iron, it uses the same gas that cigarette lighters use and you can change the tip from soldering iron to hot knife to hot air, the hot air and knife are what I use for welding plastic.

If you can see what the plastic material is you can buy the right welding rods

I would also suggest testing on a part that won't affect it, maybe one of the flanges, that way you can play around but also test you have the right welding rods.

I have an ancient (I mean .. it came from Maplin when they was still a thing) gas soldering iron with a welding tip - I just ordered a set of rods of various kinds, though I'd assume the intake manifolds would be ABS or maybe glass fibre polycarbonate.

Chatting to a friend of mine, he's had to do the same on his six-cylinder Subaru because those have the exact same problem, so I'll rope him in and that way if he makes it any worse it's his fault

Also found these: https://www.island-4x4.co.uk/engine-parts-...mp;sort=3a

They have three choices of manifold - OE at £540, Britpart at £310 or "aftermarket" at £150 (all ex VAT) - £180 is a very tempting price vs the other options I'd found (£350ish).

And just now.. https://www.neobrothers.co.uk/car-parts/en...8-lr005659 - £107 inc VAT! 2014 BMW 530d Touring, 2006 BMW 650i, 2018 Mini Cooper S

Col wrote:

Not sure if you have this or not, but a list of L/R's possible causes may help.



Cheers
Col

Soo just bumping this - the car hasn't been used much while I pondered what to do and dealt with general life stuff instead; but I gave it a run over to my mum's today (Northampton to Peterborough - up the A605 for the locals - and I realised something..

I can tell when it's going to throw a fault code because the car will suddenly feel very sluggish when applying throttle.. that and the fact that the car behind me will disappear into a cloud of soot (sorry, polar bears!). If I immediately get off the throttle and stab it open again, the problem clears and the car regains all it's power.

I'm actually thinking maybe I was too quick to condemn the intake manifolds without testing now, and perhaps what I have is either a sticking turbo actuator or, more likely, a sticking EGR valve (although it hasn't thrown an EGR fault). If it was a leaking inlet manifold or split hose I wouldn't expect it to immediately clear like that (a split wouldn't spontaneously heal, would it..), but a stuck EGR might pop loose when the actuator is cycled, likewise maybe the turbo actuator.

The car previously had new EGR valves (likely non genuine as the supplying dealer fitted them under warranty so I'm going to assume "cheapest part possible"!) when I bought it in 2019, and I have had to free off the turbo actuators previously..

I should really do some testing instead of stabbing around in the dark  2014 BMW 530d Touring, 2006 BMW 650i, 2018 Mini Cooper S

Hi, i see your post and its been some time since you updated it. I seem to have the same issue. Did you ever find out what the problem was? It would be really good to know if you did.

I didn't - the car went to WBAC in the end and became someone elses money pit after sitting on the drive for nearly a year because it was just too unreliable; replaced by a 2014 BMW 530d.

Sorry! 2014 BMW 530d Touring, 2006 BMW 650i, 2018 Mini Cooper S

Thats what I'm thinking also. Such a shame.

The thing is i will never buy a RR again, it's put me off for life. I think a lot of people would think the same.

You didn't end up with YF59FFH, did you? (My old car) 2014 BMW 530d Touring, 2006 BMW 650i, 2018 Mini Cooper S