From memory, Turbos will only spool up with engine pressure, ie under load. Simply reving an engine won’t necessarily generate the right pressures for turbos to spoil up correctly.

Noticed another thread on. L405 4.4V8 TDV8.....bad battery also threw up the same intermittent restricted power mode.

So, plan of action and plenty to go at with the dealer

Battery. - 12.15v so easy start point. - I always remember that 90% of failures are electrical, battery, sensors etc
Top plenum and rubbers - smoke test
Secondary valve
EGR
Check fault codes

Thanks guys. Really appreciate your thoughts and comments

Best regards
Mark

A sticky inlet isolation valve will trigger restricted performance. An improved valve was fitted during the MY11-12 production run but my money is on the battery.

My car a late 2011 model so it might have the latest valve fitted.

It’s only done 48k miles and the engine bay is as clean as a whistle so far!

Namb you’re right at constant revs not under load the turbos won’t boost but if you hit full throttle from idle you will get a quick blip of boost as the engine revs up BMW i3 Electric Car
2012 Full Fat RR 4.4 TDV8 (now gone)
2006 VW Touareg 3.0 TDi V6

nambFFRR wrote:

My car a late 2011 model so it might have the latest valve fitted.

old style valve.

So.....
Could this be the leak? It seems so insignificant given the cars only done 48k miles. This is more like a weep than a split in the plenum. There isn’t anything on the 4 rubbers. What do you folks think?

Click image to enlarge

nambFFRR wrote:

My car a late 2011 model so it might have the latest valve fitted.

It’s only done 48k miles and the engine bay is as clean as a whistle so far!

Mine is a May2011 and had the old style valve with the nut, but if that is your problem you will know by reading the Fault codes, because it gives out an obvious fault code when sticking.
Mike. G reg 2.5VM Vogue Portofino red 1991- 1999
V reg 2.5td P38 Rioja red 1999- 2006
53 reg td6 Vogue Oslo blue 2006- 2015
11 reg 4.4 TdV8 Vogue SE. Baltic blue 2015- date.
https://www.fullfatrr.com/forum/topic56162...tty+affair

That’s what I’m hoping for. If a code is there that points to something specific there’s a chance it will be an easy fix.

Just checked....mine was registered 28/07/11 so might have the old valve....I’ll have to have a look....

The small split in the seam of the plenum is very similar to what other members have reported as causing the problem giving restricted performance problems, particularly under load.
Mike. G reg 2.5VM Vogue Portofino red 1991- 1999
V reg 2.5td P38 Rioja red 1999- 2006
53 reg td6 Vogue Oslo blue 2006- 2015
11 reg 4.4 TdV8 Vogue SE. Baltic blue 2015- date.
https://www.fullfatrr.com/forum/topic56162...tty+affair

I’ll point the technician in that direction if that’s the case. I’d have expected a larger breach/split with more evidence (oil/soot on the engine and engine cover) than what I can currently see. Does this problem throw up an error code which pinpoints the split or drop in pressure or is it more generic? The only sensor I can see is the MAP sensor on the front section....are there any others for pressure in the system?

Think the garage have pinpointed 2 faults.....minor split on the top plenum and weak battery. Both as suspected. Both now replaced. I’ll report back with any further info later this evening once I pick the car up and have had a chance to chat about the fixes they’ve done. I’ll try and find out what codes these faults threw up for future reference.