Can You Help Identify My Diesel Problem Please

jeremy · 14th November 2017, 13:06

I have a much-loved Rover 75 Connoisseur Tourer diesel automatic of January 2004 vintage and about 95,000 on the clock. Recently a problem has developed which sees the vehicle lose power particularly on the motorway. Typically it is cruising happily away at about 110kph and for no reason will suddenly not respond to the accelerator. It will gradually slow down, noticeably going uphill or struggle to maintain speed. If I'm lucky it will cure itself for no apparent reason but this seems to take longer than before and last night I thought I wouldn't make it home. Putting your foot hard down to increase speed just leads to dropping a gear but no regaining of speed. On the odd occasion the engine has refused to start for several minutes.

I have tried to puzzle out possible causes but without success. I fitted a cruise control a couple of years ago but that caused no difficulties back then. It does seem to correlate with filling up the tank but we tend to do that often before a motorway journey anyway. I even disconnected the battery for several hours but that made no difference.

My intuition is that it is a fuel problem and I suspect that it might be a problem with the in-tank pump.

I would be really grateful if someone could advise me. I have an excellent local garage but the mechanic hardly ever sees these cars.

Jeremy

Greeners · 14th November 2017, 13:11

Check the plenum for water ingress as a start

I suspect one of the T4 guys will soon steer you in the right direction

COLVERT · 14th November 2017, 20:29

It has been known for the crank sensor to cause that sort of problem.--

grivas · 15th November 2017, 20:45

Quote:

Originally Posted by jeremy

I have a much-loved Rover 75 Connoisseur Tourer diesel automatic of January 2004 vintage and about 95,000 on the clock. Recently a problem has developed which sees the vehicle lose power particularly on the motorway. Typically it is cruising happily away at about 110kph and for no reason will suddenly not respond to the accelerator. It will gradually slow down, noticeably going uphill or struggle to maintain speed. If I'm lucky it will cure itself for no apparent reason but this seems to take longer than before and last night I thought I wouldn't make it home. Putting your foot hard down to increase speed just leads to dropping a gear but no regaining of speed. On the odd occasion the engine has refused to start for several minutes.

I have tried to puzzle out possible causes but without success. I fitted a cruise control a couple of years ago but that caused no difficulties back then. It does seem to correlate with filling up the tank but we tend to do that often before a motorway journey anyway. I even disconnected the battery for several hours but that made no difference.

My intuition is that it is a fuel problem and I suspect that it might be a problem with the in-tank pump.

I would be really grateful if someone could advise me. I have an excellent local garage but the mechanic hardly ever sees these cars.

Jeremy

What do you see on the rev dial when this happens and the car does not respond to accelerator do revs rise without a corresponding rise in speed?

clf · 15th November 2017, 20:54

Purely a guess based on you saying 'noticeably going uphill ', I would agree with your thoughts on the intank pump, however how much fuel is in the tank when these instances occurred? If a quarter or less, based on what I read of others' experiences, I would suggest the intank pump starting to fail, or has failed.

RPWC · 15th November 2017, 21:00

Quote:

Originally Posted by clf

Purely a guess based on you saying 'noticeably going uphill ', I would agree with your thoughts on the intank pump, however how much fuel is in the tank when these instances occurred? If a quarter or less, based on what I read of others' experiences, I would suggest the intank pump starting to fail, or has failed.

But the under bonnet pump will still be operating.

NigelOBB · 15th November 2017, 21:35

When was the diesel filter last changed

Sent from my iPhone using Tapatalk

Avulon · 15th November 2017, 22:19

Quote:

Originally Posted by RPWC

But the under bonnet pump will still be operating.

Won't help if there's insufficient fuel pressure from the tank, Above a third full there's enough for the UBP to manage on it's own, much below that and it will struggle to maintain enough pressure through the filter head (where the low pressure fuel sensor is located) without the intank pump running properly. Insufficient pressure will cause the ecu to shut down the injectors.

NigelOBB · 16th November 2017, 09:47

Quote:

Originally Posted by Avulon

Won't help if there's insufficient fuel pressure from the tank, Above a third full there's enough for the UBP to manage on it's own, much below that and it will struggle to maintain enough pressure through the filter head (where the low pressure fuel sensor is located) without the intank pump running properly. Insufficient pressure will cause the ecu to shut down the injectors.

My Connie has been running on one pump for a while, it has starting problems if it drops below 1/4.. really need to sort it

Sent from my iPhone using Tapatalk

jeremy · 16th November 2017, 11:44

Thanks to everyone.

Checked the plenum and it is bone dry. I have always looked after that!
Yes, the revs rise but the speed does not. It seems to be just dropping down a gear.
There has always been plenty of fuel in the tank and at least half full when the problem recurred the other day.
The under bonnet pump seems fine as I can hear it and feel the vibrations.
Took the rear seat squab out yesterday and I can certainly hear a noise from the in-tank pump. It was more of a whirring than a humming but it "seemed" to be right.
I changed the diesel filter about 10k ago with an original part.
I can say for a fact that there has been plenty of fuel in the tank when these situations happen.
I took it down the road this morning. Started fine, no problems. Came out of the shop turned on ignition, waited a few seconds (as I normally do) and then tried to start it but no success although the starter motor was turning fine. On the 6th attept it started and was fine.
I am stumped!!
Many thanks to everyone for their comments.
Is this something that can be identified through a diagnostic machine and does anyone know of one near Limerick?
Jeremy

14th November 2017, 13:06	#1
jeremy Avid contributor Rover 75 Tourer Join Date: May 2013 Location: Limerick Posts: 106 Thanks: 71 Thanked 24 Times in 16 Posts	Can You Help Identify My Diesel Problem Please I have a much-loved Rover 75 Connoisseur Tourer diesel automatic of January 2004 vintage and about 95,000 on the clock. Recently a problem has developed which sees the vehicle lose power particularly on the motorway. Typically it is cruising happily away at about 110kph and for no reason will suddenly not respond to the accelerator. It will gradually slow down, noticeably going uphill or struggle to maintain speed. If I'm lucky it will cure itself for no apparent reason but this seems to take longer than before and last night I thought I wouldn't make it home. Putting your foot hard down to increase speed just leads to dropping a gear but no regaining of speed. On the odd occasion the engine has refused to start for several minutes. I have tried to puzzle out possible causes but without success. I fitted a cruise control a couple of years ago but that caused no difficulties back then. It does seem to correlate with filling up the tank but we tend to do that often before a motorway journey anyway. I even disconnected the battery for several hours but that made no difference. My intuition is that it is a fuel problem and I suspect that it might be a problem with the in-tank pump. I would be really grateful if someone could advise me. I have an excellent local garage but the mechanic hardly ever sees these cars. Jeremy

14th November 2017, 13:11	#2
Greeners Moderator MG-ZTT Join Date: Mar 2007 Location: Ware, Herts Posts: 19,798 Thanks: 161 Thanked 1,249 Times in 1,036 Posts	Check the plenum for water ingress as a start I suspect one of the T4 guys will soon steer you in the right direction __________________ *David* Impecunity is the mother of ingenuity Useful how to's for common problems Car Of The Month Jan 2014 [SatNav Power Down] [Coolant Level] [SatNav Repair] [Diesel Non Starting] [Paint Codes] [Rear Light Seals] [Reversing Light Switch] [Bleeding Brakes][Sunroof Drain] [Early ZT's][Instrument Pack Diagnostics][ATC Diagnostics]

15th November 2017, 20:54	#5
clf This is my second home MG ZT CDTi Join Date: Jan 2014 Location: carrick Posts: 7,859 Thanks: 3,494 Thanked 2,657 Times in 1,973 Posts	Purely a guess based on you saying 'noticeably going uphill ', I would agree with your thoughts on the intank pump, however how much fuel is in the tank when these instances occurred? If a quarter or less, based on what I read of others' experiences, I would suggest the intank pump starting to fail, or has failed. __________________ It is not gloss primer .............. it is duct tape silver!

15th November 2017, 21:35	#7
NigelOBB This is my second home 04 Rover 75 Contemporary SE - 53 Rover 75 Connoisseur -94 Mercedes W140 - 72 VW Beetle 1300 Join Date: Sep 2012 Location: Sunderland Posts: 4,767 Thanks: 1,379 Thanked 493 Times in 429 Posts	When was the diesel filter last changed Sent from my iPhone using Tapatalk __________________ [SIGPIC][/SIGPIC] Keep smiling - it makes people wonder what you've been up to.

14th November 2017, 20:29	#3
COLVERT This is my second home R75 Saloon. Join Date: Feb 2009 Location: France/or Devon. Posts: 14,003 Thanks: 3,851 Thanked 2,167 Times in 1,816 Posts	It has been known for the crank sensor to cause that sort of problem.--

16th November 2017, 11:44	#10
jeremy Avid contributor Rover 75 Tourer Join Date: May 2013 Location: Limerick Posts: 106 Thanks: 71 Thanked 24 Times in 16 Posts	Thanks to everyone. Checked the plenum and it is bone dry. I have always looked after that! Yes, the revs rise but the speed does not. It seems to be just dropping down a gear. There has always been plenty of fuel in the tank and at least half full when the problem recurred the other day. The under bonnet pump seems fine as I can hear it and feel the vibrations. Took the rear seat squab out yesterday and I can certainly hear a noise from the in-tank pump. It was more of a whirring than a humming but it "seemed" to be right. I changed the diesel filter about 10k ago with an original part. I can say for a fact that there has been plenty of fuel in the tank when these situations happen. I took it down the road this morning. Started fine, no problems. Came out of the shop turned on ignition, waited a few seconds (as I normally do) and then tried to start it but no success although the starter motor was turning fine. On the 6th attept it started and was fine. I am stumped!! Many thanks to everyone for their comments. Is this something that can be identified through a diagnostic machine and does anyone know of one near Limerick? Jeremy