cdt surging

shielsy · 13th March 2008, 11:14

Has any one suffered this problem. with the car sitting at approx 2000rpm the car surges and seems like it is holding back you can eccelerate through it but as my car at 2000 revs is 70mph this can be very annoying i have ron box 2 and new maf also new pcv and cleaned erg the car has been on t4 and no faults show its got me so any ideas cheers shielsy

apywell · 13th March 2008, 18:16

No such problem with mine......

Simon · 13th March 2008, 19:39

First thing to do is to remove all the extras you've fitted and see if you still get the same problem. Then add each modification one by one until the problem returns.

Jules · 13th March 2008, 19:46

Good tips Simon!
Also Sheilsy what is the age & mileage of your car?
Up to around 2003 there were 2 fuel pumps. The secondary one ( eliminated in later models) is near the battery.
These only have a life of 60K - 80K miles (these sealed pumps suffer from brush wear)

shielsy · 14th March 2008, 12:09

she is an old girl 1999 and covered 133000

Jules · 14th March 2008, 13:06

I would certainly check BOTH fuel pumps then! Pressure check at a diesel diagnostics type place

ikorodu · 14th March 2008, 13:36

Quote:

Originally Posted by shielsy

Has any one suffered this problem. with the car sitting at approx 2000rpm the car surges and seems like it is holding back you can eccelerate through it but as my car at 2000 revs is 70mph this can be very annoying i have ron box 2 and new maf also new pcv and cleaned erg the car has been on t4 and no faults show its got me so any ideas cheers shielsy

Hello,

I have a similar experience in mine. To me it feels like a sudden from in fueling, but as you say accelerate and you can get through it. Mine is a 2004 model, so I assume it has a single fuel pump in the tank and nothing under the bonnet.

I too have a ron box and mafam, not looked at pcv or egr but its only done 29000 miles so they should be reasonable. Have tried removing the ron box and the problem remained, it was also present before the mafam was fitted. The fuel filter was replaced yesterday and that has not solved it either.

By the way I also have another issue in that when flooring the throttle I get the engine light on breifly accompained by this 'holding back', if I keep the throttle down the light goes out and it then revs all the way to the redline.

My current thinking is that its a fuel pump issue, but I'm unsure how to fault find this myself and am a bit strapped for cash to pay for a diesel specialist look at it.

Would be very interested to hear if you get anywhere on your problem as it may help with mine.

Rob

Keith · 14th March 2008, 17:34

The mil light could be a sign of low fuel pressure, the sensor for this is the one on the fuel filter housing

I am not sure how this would manifest itself via the engine ECU control but it could reduce the amount of fuel being injected and hence the feeling of delay at the pedal

A good clean of the connections might be a starting point

A sesion on T4 to verify the fuel pump outputs should show if one has failed or not as the pressure will be low i.e if less than <300 kpa I would suspect a failing or failed pump

ikorodu · 15th March 2008, 05:28

Can anyone confirm that the under bonnet pump was deleted from diesels at some point?

Thanks

Rob

Jules · 15th March 2008, 12:58

Yes around 53 Plate but some 2004 models had them.

13th March 2008, 11:14	#1
shielsy Regular poster rover 75 saloon Join Date: Feb 2008 Location: ESSEX Posts: 33 Thanks: 0 Thanked 0 Times in 0 Posts	cdt surging Has any one suffered this problem. with the car sitting at approx 2000rpm the car surges and seems like it is holding back you can eccelerate through it but as my car at 2000 revs is 70mph this can be very annoying i have ron box 2 and new maf also new pcv and cleaned erg the car has been on t4 and no faults show its got me so any ideas cheers shielsy

13th March 2008, 18:16	#2
apywell Gets stuck in Rover 75 Saloon. 2.0 Diesel Auto. Connoisseur SE. Join Date: Nov 2006 Location: Derby Posts: 723 Thanks: 0 Thanked 0 Times in 0 Posts	No such problem with mine...... __________________ If there's one thing I've learned, it's that life is one crushing defeat after another until you just wish Flanders was dead. Now has an S-Type 2.7 diesel V6 twin turbo with Jag voice, bluetooth, sat nav, front and rear park assist, electric fold mirrors etc, etc, etc.....

13th March 2008, 19:46	#4
Jules This is my second home ZT 260 SE Twilight and 10 other 75 ZT's :O Join Date: Jan 2007 Location: Conwy NORTH WALES Posts: 11,094 Thanks: 512 Thanked 1,116 Times in 763 Posts	Good tips Simon! Also Sheilsy what is the age & mileage of your car? Up to around 2003 there were 2 fuel pumps. The secondary one ( eliminated in later models) is near the battery. These only have a life of 60K - 80K miles (these sealed pumps suffer from brush wear) __________________ [SIGPIC][/SIGPIC] Newbies do now!! 1. Plenum drains..all 3 or 4 year dependent 2. Cooling fan..All speeds functioning 3. Bonnet cable divider block

14th March 2008, 13:06	#6
Jules This is my second home ZT 260 SE Twilight and 10 other 75 ZT's :O Join Date: Jan 2007 Location: Conwy NORTH WALES Posts: 11,094 Thanks: 512 Thanked 1,116 Times in 763 Posts	I would certainly check BOTH fuel pumps then! Pressure check at a diesel diagnostics type place __________________ [SIGPIC][/SIGPIC] Newbies do now!! 1. Plenum drains..all 3 or 4 year dependent 2. Cooling fan..All speeds functioning 3. Bonnet cable divider block

15th March 2008, 12:58	#10
Jules This is my second home ZT 260 SE Twilight and 10 other 75 ZT's :O Join Date: Jan 2007 Location: Conwy NORTH WALES Posts: 11,094 Thanks: 512 Thanked 1,116 Times in 763 Posts	Yes around 53 Plate but some 2004 models had them. __________________ [SIGPIC][/SIGPIC] Newbies do now!! 1. Plenum drains..all 3 or 4 year dependent 2. Cooling fan..All speeds functioning 3. Bonnet cable divider block

13th March 2008, 19:39	#3
Simon Banned - Join Date: Nov 2006 Location: - Posts: 10,318 Thanks: 0 Thanked 4 Times in 3 Posts	First thing to do is to remove all the extras you've fitted and see if you still get the same problem. Then add each modification one by one until the problem returns.

14th March 2008, 12:09	#5
shielsy Regular poster rover 75 saloon Join Date: Feb 2008 Location: ESSEX Posts: 33 Thanks: 0 Thanked 0 Times in 0 Posts	she is an old girl 1999 and covered 133000

14th March 2008, 17:34	#8
Keith This is my second home ZT400 Join Date: Oct 2006 Location: Ellesmere Posts: 5,948 Thanks: 0 Thanked 43 Times in 29 Posts	The mil light could be a sign of low fuel pressure, the sensor for this is the one on the fuel filter housing I am not sure how this would manifest itself via the engine ECU control but it could reduce the amount of fuel being injected and hence the feeling of delay at the pedal A good clean of the connections might be a starting point A sesion on T4 to verify the fuel pump outputs should show if one has failed or not as the pressure will be low i.e if less than <300 kpa I would suspect a failing or failed pump

15th March 2008, 05:28	#9
ikorodu Loves to post Rover 75 Facelift Conn SE Tourer CDTi Manual Join Date: Jan 2007 Location: Nottinghamshire Posts: 269 Thanks: 0 Thanked 11 Times in 1 Post	Can anyone confirm that the under bonnet pump was deleted from diesels at some point? Thanks Rob