MG ZT CDTI engine idle speed fluctuating when warming up.

rikk · 14th December 2018, 10:25

Hello, Just recently I’ve noticed that when my ZT CDTI auto is warming up, the engine revs are going up and down .. maybe by 50-100 rpm.. quite rapidly. Once it’s warmed up it stops doing this and the idle speed is stable. It’s not a big problem at the moment but it didn’t do this until recently (not sure if it’s because of the colder weather but I don’t remember it doing it last winter). Any ideas what could cause this – a dodgy sensor maybe?

Thankyou.

COLVERT · 15th December 2018, 18:26

No response !! Oh, well----How about glow plugs cutting in and out until the engine warms up a little. ( The plugs stay on a while after the dash light goes out. ) Plug relay points not too good ???

14th December 2018, 10:25	#1
rikk Avid contributor Rover 75 CDTI Join Date: Mar 2007 Location: Ashby de la Zouch Posts: 104 Thanks: 3 Thanked 2 Times in 2 Posts	MG ZT CDTI engine idle speed fluctuating when warming up. Hello, Just recently I’ve noticed that when my ZT CDTI auto is warming up, the engine revs are going up and down .. maybe by 50-100 rpm.. quite rapidly. Once it’s warmed up it stops doing this and the idle speed is stable. It’s not a big problem at the moment but it didn’t do this until recently (not sure if it’s because of the colder weather but I don’t remember it doing it last winter). Any ideas what could cause this – a dodgy sensor maybe? Thankyou.

15th December 2018, 18:26	#2
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	No response !! Oh, well----How about glow plugs cutting in and out until the engine warms up a little. ( The plugs stay on a while after the dash light goes out. ) Plug relay points not too good ???