Irratic idling

crashmarks · 29th September 2011, 22:15

I have a 35k cdti auto with a synergy set on no 2. In the last week or so i have noticed that when I pull up at traffic lights or a junction that my idling speed is fluctuating almost rythmicly by about 50 revs. If I take it out of gear it becomes much less and if I put the aircon on with it in gear it gets worse. So it seems to be load dependent. Other than that the car is running perfectly. Any ideas ?? Is there an idle control sensor.

The egr valve and air filters are clean and theres no sump back pressure.

Big Fra · 30th September 2011, 02:04

I'm getting the exact same symptoms with my 75.
I'm gonna replace the PCV filter to see how that works.

Have a look at this thread.

http://www.the75andztclub.co.uk/foru...ad.php?t=93993

chrissyboy · 30th September 2011, 13:08

could be an airleak the car is sucking in extra air that isnt being monitored so hence the irratic idle

COLVERT · 30th September 2011, 14:56

Could be leakback on one injector.

The extra load will be sensed by the ECU which will send a signal for more fuel. ( Aircon on )

Three injectors could be supplying more fuel but a leaky one the same.

The extra push you'd get from the three running normally would probably give an even more irregular tickover.

Maybe.

crashmarks · 30th September 2011, 17:44

Cheeers guys I will try those suggestions and update in due course.

Mike Noc · 30th September 2011, 23:06

Quote:

Originally Posted by chrissyboy

could be an airleak the car is sucking in extra air that isnt being monitored so hence the irratic idle

Not on a diesel as they take a full charge of air in during each cycle - there is no throttling. That's why they have to fit a separate vacuum pump.

Mike

James.uk · 1st October 2011, 01:19

At 35K I seriosuly doubt it's an injector problem..

Alter the setting on the Synergy, if you ferkle about with the settings you should find one that suits the car and the tickover will settle down..

...

29th September 2011, 22:15	#1
crashmarks Loves to post Rover 75 Connoisseur SE Tourer Auto Join Date: Feb 2010 Location: Wakefield Posts: 408 Thanks: 12 Thanked 8 Times in 8 Posts	Irratic idling I have a 35k cdti auto with a synergy set on no 2. In the last week or so i have noticed that when I pull up at traffic lights or a junction that my idling speed is fluctuating almost rythmicly by about 50 revs. If I take it out of gear it becomes much less and if I put the aircon on with it in gear it gets worse. So it seems to be load dependent. Other than that the car is running perfectly. Any ideas ?? Is there an idle control sensor. The egr valve and air filters are clean and theres no sump back pressure.

30th September 2011, 02:04	#2
Big Fra Avid contributor Vauxhall Insignia Join Date: Jul 2011 Location: Blantyre Posts: 206 Thanks: 0 Thanked 0 Times in 0 Posts	I'm getting the exact same symptoms with my 75. I'm gonna replace the PCV filter to see how that works. Have a look at this thread. http://www.the75andztclub.co.uk/foru...ad.php?t=93993 __________________ WHEN WILL IT END? ER, it has!

30th September 2011, 13:08	#3
chrissyboy This is my second home lovely little ford focus. Join Date: Jul 2009 Location: East Dulwich Posts: 7,877 Thanks: 2 Thanked 82 Times in 68 Posts	could be an airleak the car is sucking in extra air that isnt being monitored so hence the irratic idle __________________ [ I'm really confused. -I keep dreaming I'm an insomniac

1st October 2011, 01:19	#7
James.uk Passed Away 2002 Pale Blue. Rover 75 CDTi Connoisseur auto. 170K miles Join Date: Dec 2008 Location: Near the M67. Posts: 14,509 Thanks: 199 Thanked 585 Times in 397 Posts	At 35K I seriosuly doubt it's an injector problem.. Alter the setting on the Synergy, if you ferkle about with the settings you should find one that suits the car and the tickover will settle down.. ... Last edited by James.uk; 1st October 2011 at 01:21..

30th September 2011, 14:56	#4
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	Could be leakback on one injector. The extra load will be sensed by the ECU which will send a signal for more fuel. ( Aircon on ) Three injectors could be supplying more fuel but a leaky one the same. The extra push you'd get from the three running normally would probably give an even more irregular tickover. Maybe.

30th September 2011, 17:44	#5
crashmarks Loves to post Rover 75 Connoisseur SE Tourer Auto Join Date: Feb 2010 Location: Wakefield Posts: 408 Thanks: 12 Thanked 8 Times in 8 Posts	Cheeers guys I will try those suggestions and update in due course.