OK, first things first.... Thanks to everyone who continues to help me, this is a great forum!
Secondly....some of you have seen my previous two threads that resulted in a trip to Autolusso Bournemouth and the blanking and mapping out of the EGR along with a steam clean of the Main CAT. This made a BIG difference and MPG jumped from very low 30's to very low 40's when Brim to Brim'd. Big thanks still goes to Loz as the EGR wasnt throwing codes and mapping it out worked well.
Lastly...the "increased engine braking" is a symptom that has been with the car before the egr deleting and my changing of the MAF but has now become more pronounced now that the car is running so much better. I have found myself having to give the car some throttle when going down hill on occassions when I really shouldn't have to, my colleagues Saab 9-3 tid (1.9 16v, same engine) had virtually no engine braking whatsoever and today my other colleague who is used to a Passat 2.0 diesel said even in the passenger seat it feels like somebody is applying the brakes when I lifted off on the flat at 50 mph.
No throttle = no exhaust, no exhaust = no turbo spool, no turbo spool = no forced induction... If the filter is ********ed then it could be providing resistance to the natural aspiration of the engine when the fuel is cut...
Thanks - The filter is brand new and I believe is installed correctly. I took the chance to change it when I had the battery out and this gave alot more room.
it could but hopefully not as hes just had it cleaned out, there has unfortunately been other issues with this car lately(in many different threads, which makes it a bit harder to follow the issues).
Hi again.........The main CAT was cleaned out only, not the Pre Cat. Thanks.
Maybe a blocked catalytic converter that is causing a lot of back pressure?
Thanks - as above really, main CAT was steam cleaned and confirmed as clear. Pre CAT has not been touched.
I don't think it can be the gearbox:
If the output shaft/diff was seizing, going into neutral would not help.
If the input shaft was seizing the gearchange would be difficult.
Too much oil would increase resistance, but again, going into neutral would not help.
I've just been reading your thread in 'the other place', you could use your software to monitor the inlet manifold pressure on overrun (should be close to atmospheric pressure) That would rule out resistance in the inlet system, which seems unlikely, but since it's easy to check you may as well.
It was interesting that the Rover owner found changing his turbo worked, even though the old one was producing boost, but since your VNT works it seems unlikely that's the problem.
Which leaves the pre-cat (surely not the silencer?). Or, unlikely but worth checking:
A short circuit in the alternator. Since it is a three phase machine it could still give some charge, but if you can get a hand to it, it would be VERY hot after a run. It's a large alternator and could probably produce a braking effort equivalent to 4 hp.
Hi again R.T -
Agreed on the gearbox.
Boost pressure vs atmospheric pressure graphs below - 2 of these were taken accelerating/coasting up and down a very large, flat and empty car park tonight and one was taken on the road down hill.
Down hill - on the road
What do we reckon, looks ok to me?
Rover forum - yes my VNT seems
to work ( see graph below) but his symptoms are the only I can find on the internet that match mine 100%.
Blocked Pre CAT? Maybe....I'm led to believe they get too hot to block though.
I read your message on my phone in between driving home and ended up forgetting to check the alternator. I have no idea about this myself but I will definitely check this tomorrow morning if not tonight.
as above, a quick log of total fuel maf airflow and boost pressure with vnt% should help see whats what.
if you find a slight downhill and lift off totally accelerator , fuel should go to zero mg/I, maf around 480-500 and boost around 980-1050mbar.
did yours have swirl flaps? could cause a restriction if broke and fully shut .
been like this before or after the oil issue , before or after the cat clean , egr delete.
Sussexa - see graphs below, mine definitely doesnt have swirl flaps (thank god). The engine braking has been like it before the cat clean and egr delete just more pronounced now its running so much better and it was the last of my worries back then. Whether it was there before the oil incident I cant 100% remember but I think it was.
Fuel only - accelerating and then coasting on the flat:
Fuel vs maf vs boost vs VGT - accelerating and coasting in 2nd gear on flat (VGT looks ok to me) :
Sames as the above but in third & fourth gears:
and again same as the above, 3rd & 4th gears but a very short down hill on a small road:
Massive Post.....Sorry. Hope somebody can make something out of everything above. I have yet to properly study the graphs as I have just got in and decided to post it straight on here. Ill have a proper look after hitting submit on this message....Thanks again.