2.0 CDti - Won't rev past 2500 rpm, or change down gear
 

Hi forumites, during this lockdown I've not driven my 75 CDti much at all except for a pop to the shops, and the car has been mostly sitting on the driveway in this lovely weather, otherwise it had been driven on long commutes and distances - North Wales to Birmingham and Edinburgh without any fuss or bother.

I took her out the other day for a run this week (to Chester), but find I've lost top end power, and it won't accelerate past 2500 rpm, or change down gear/ kick down once I get her up through fourth and to 50 mph.

I've been through various other threads, and not had much success and a lot of the older threads have no photo links for me to follow.
I did disconnect the MAF sensor, but it still won't rev up, even in Neutral.

There are no engine management warning lights, no smokiness from the exhaust, everything is running smoothly at low revs, it's just refusing to "push on"

Check and clean the LP fuel pressure sensor plug connection - it is the one on top of the fuel filter.

Quick Update
 

I've now reassembled everything, and now the ignition won't fire :-(
I'm beginning to wonder if it may be a fuel pump problem ?

Thanks Mike - Just got to locate that now ;-)

Quick Google and seen that you've posted on this a fair few times :-D
Will have a look after my bacon butty

It is on top of the fuel filter housing, attached to the inboard side of the battery box Bruce ;)

Your symptoms hint at low fuel pressure, how much is in the tank, and if the answer is 1/4 or less, you need to put more fuel in before condemning the underbonnet fuel pump, located just behind the fuel filter, as there will be a possibility the in tank fuel pump is not working :)

Brian :D

Half a tank - popped £20 in the other day

Usual problems I guess of running too low on diesel, seems to be a recurring theme on the forum

It sounds like the underbonnet fuel pump is at fault in that case, if there is a 12v supply between the white and purple and the black wire entering the plug on the top of the pump, another alternative is a blocked or collapsed fuel filter.

Try this, ignition on position 2 for 30 seconds, then off, repeat but at the end of the 30 seconds crank the car to see if it will start.

Brian :D

Belated update
 

Much thanks has to go out to Jules, with whom I got in touch over this issue.
As he's not too far down the coast from my abode in N Wales I was able to drop my Conny in with him to diagnose the issues.
Ironically on the day I drove down there were actually no problems with power delivery at all :duh:
Fortunately Jules has the kit to investigate these matters, the fuel pressures were coming it at approx 210 psi(?) and we replaced both the Under Bonnet and Fuel Tank pumps.
Pressure delivery is now around the 270 mark, and there have been no further issues at all :bowdown:

He also discovered a worn drop link, and was also able to track down the faulty wiring on the NS Headlamp
https://the75andztclub.co.uk/forum/s...d.php?t=303510
And ran in a new connection for me.

Also able to get a few other bits and bobs resolved :-)
So if you're in need of help in North Wales, Jules is definitely the man to go to

Good to hear you are sorted. :}