Car hunting after about 3 mins when running the climate control

phatfiesta75 · 6th September 2018, 00:49

Hi guys gotta feeling i'll be posting a fair view questions with different things regarding my contemporary se cdti 54 plate anyway as title suggests when using my climate control the revs start hunting when idling don't notice when moving but as soon as i stop at lights or just stay parked up while engine running the cars revs start to hunt but stops if I turn the econ button on🤔 any idea's or if anyone has come across the same thing?
Thanks in advance 🙂

macafee2 · 6th September 2018, 06:40

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macafee2

RoverP480 · 6th September 2018, 07:25

Quote:

Originally Posted by phatfiesta75

when using my climate control the revs start hunting when idling but stops if I turn the econ button on�� any idea's or if anyone has come across the same thing?
Thanks in advance ��

I wonder if the air con is low on gas

Mike Trident · 6th September 2018, 08:14

That has to be related to the compressor, it must be hard for the engine to spin it for some reason.

phatfiesta75 · 6th September 2018, 10:31

Quote:

Originally Posted by macafee2

ask as many questions as you like

macafee2

Thanks macafee2 🙂

phatfiesta75 · 6th September 2018, 10:34

Quote:

Originally Posted by RoverP480

I wonder if the air con is low on gas

Hmm I don't know it's definitely cold and definitely feels more so when driving. Hmm....think i best get it checked out. Thanks

phatfiesta75 · 6th September 2018, 10:38

Quote:

Originally Posted by Mike Trident

That has to be related to the compressor, it must be hard for the engine to spin it for some reason.

Think like rover P480 you could be on to something mike. yeah best go get it checked out at a garage that checks aircon Thanks again everyone 🙂

SD1too · 6th September 2018, 10:40

Quote:

Originally Posted by Mike Trident

That has to be related to the compressor ...

Ooooohhh, hang on a minute Mike! We've heard that diagnosis in cases when we know that the crankshaft pulley is the real culprit.

Now, I'm not familiar with the diesel engine but you will be. What mechanism does it have for idle speed control and could there be a fault with that? I mention this because here is what RAVE has to say about the petrol engine management system:

A [PWM] signal from the alternator is produced that indicates the amperage currently being produced. The EMS will alter its idle strategy to compensate for high current draw from the alternator. If the signal fails, you may notice poor idle characteristics when the battery is in a low state of charge or there is a heavy electrical load. The ECM will store a fault code.

The air conditioning compressor clutch is a heavy electrical load, so I am recommending caution in pointing the finger of blame at the compressor. Likewise, low refrigerant level won't cause idle variations. I imagine that the diesel engine has more than enough torque to cope with the demands of the air conditioning compressor.

Simon

phatfiesta75 · 6th September 2018, 10:56

Quote:

Originally Posted by SD1too

Ooooohhh, hang on a minute Mike! We've heard that diagnosis in cases when we know that the crankshaft pulley is the real culprit.

Now, I'm not familiar with the diesel engine but you will be. What mechanism does it have for idle speed control and could there be a fault with that? I mention this because here is what RAVE has to say about the petrol engine management system:

A [PWM] signal from the alternator is produced that indicates the amperage currently being produced. The EMS will alter its idle strategy to compensate for high current draw from the alternator. If the signal fails, you may notice poor idle characteristics when the battery is in a low state of charge or there is a heavy electrical load. The ECM will store a fault code.

The air conditioning compressor clutch is a heavy electrical load, so I am recommending caution in pointing the finger of blame at the compressor. Likewise, low refrigerant level won't cause idle variations. I imagine that the diesel engine has more than enough torque to cope with the demands of the air conditioning compressor.

Simon

Thanks SD1too I hope mike may have the answer, I certainly hope it's not too expensive 😬

mystabe · 6th September 2018, 11:05

Quote:

Originally Posted by SD1too

Ooooohhh, hang on a minute Mike! We've heard that diagnosis in cases when we know that the crankshaft pulley is the real culprit.

Now, I'm not familiar with the diesel engine but you will be. What mechanism does it have for idle speed control and could there be a fault with that? I mention this because here is what RAVE has to say about the petrol engine management system:

A [PWM] signal from the alternator is produced that indicates the amperage currently being produced. The EMS will alter its idle strategy to compensate for high current draw from the alternator. If the signal fails, you may notice poor idle characteristics when the battery is in a low state of charge or there is a heavy electrical load. The ECM will store a fault code.

The air conditioning compressor clutch is a heavy electrical load, so I am recommending caution in pointing the finger of blame at the compressor. Likewise, low refrigerant level won't cause idle variations. I imagine that the diesel engine has more than enough torque to cope with the demands of the air conditioning compressor.

Simon

Yes but if the fault doesn't occur when the air con compressor clutch isn't engaged then that's probably a good place to start looking. I had a similar problem with my diesel 45 where, with the air con on, the idle was very lumpy - turn it to Econ and smooth idle again. One replacement compressor later and problem gone completely. Yes I know it's a different car and engine but

Sometimes it's best to start with the obvious

6th September 2018, 00:49	#1
phatfiesta75 Loves to post rover 75 2.0 cdti connoisseur se Join Date: Nov 2010 Location: warrington Posts: 475 Thanks: 223 Thanked 91 Times in 85 Posts	Car hunting after about 3 mins when running the climate control Hi guys gotta feeling i'll be posting a fair view questions with different things regarding my contemporary se cdti 54 plate anyway as title suggests when using my climate control the revs start hunting when idling don't notice when moving but as soon as i stop at lights or just stay parked up while engine running the cars revs start to hunt but stops if I turn the econ button on🤔 any idea's or if anyone has come across the same thing? Thanks in advance 🙂

6th September 2018, 08:14	#4
Mike Trident Posted a thing or two Rover 75 CDTi Saloon & Citroen C1 Join Date: Jun 2016 Location: Oakenshaw, Near Bradford Posts: 1,622 Thanks: 385 Thanked 552 Times in 328 Posts	That has to be related to the compressor, it must be hard for the engine to spin it for some reason. __________________ Rover 75 2.0 CDTi (131Ps) Conn SE Saloon. (Manual) 160 Remap, cruise control, electric window blind, temp gauge, Real walnut / ZT interior, FBH with GSM control. BORN Tuesday, 5th October 2004 @ 12:35:52 This vehicle was the 104,679th 75 to run off the production line, out of 112,381 This vehicle was the 3,318th 75 CDT Connoisseur SE (135) to be made out of 4,744 This vehicle was the 12,440th 75 in Starlight Silver (code: MBB) to be made out of 14,280 Starlight Silver 75s

6th September 2018, 06:40	#2
macafee2 This is my second home Rover 75 Saloon & Tourer Join Date: Sep 2012 Location: Lincoln Posts: 14,912 Thanks: 1,630 Thanked 3,032 Times in 2,181 Posts	ask as many questions as you like macafee2