"Hunting" in Volvo 740 GLT - Page 4

Laird Scooby · Sep 4th, 2018, 17:20

Is the car automatic?

What fuel have you run it on and did you recently change the fuel to a different brand? How much is in the tank?

Will the hunting occur when the engine is revved without actually traveling anywhere?

Does it happen cold, hot or both?

Peterquest · Sep 6th, 2018, 12:25

Thanks.
The fuel is the same and Kings of Witcham put more in as part of their investigation so I guess it is reasonably full.
It hunts without the car moving.
It is an auto. It happens cold or warm.

Laird Scooby · Sep 6th, 2018, 12:46

Did Kings check the ATF for level and condition and do you know when it was last changed? Sounds strange but i've known a few cars that exhibit similar symptoms due to old/contaminated ATF and on some cars can even give symptoms of a misfire under load.

Also have they checked the earth straps between engine and body?

It still sounds like an air leak somewhere though.

Peterquest · Nov 11th, 2018, 08:53

The Volvo is now fixed. It was an ECU issue - it isn't reading the idle switch correctly and thinks the idle switch is on all the time. So the overrun cut off comes on at about 1500 revs and the revs die.
Carelect diagnosed the issue when we sent over the unit and replaced part of the ECU.
Thanks for efforts to help.
Yours Peter

Sep 4th, 2018, 17:20	#31
Laird Scooby Premier Member Last Online: Today 08:43 Join Date: May 2012 Location: Lakenheath	Is the car automatic? What fuel have you run it on and did you recently change the fuel to a different brand? How much is in the tank? Will the hunting occur when the engine is revved without actually traveling anywhere? Does it happen cold, hot or both? __________________ Cheers Dave Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........

Sep 6th, 2018, 12:46	#33
Laird Scooby Premier Member Last Online: Today 08:43 Join Date: May 2012 Location: Lakenheath	Did Kings check the ATF for level and condition and do you know when it was last changed? Sounds strange but i've known a few cars that exhibit similar symptoms due to old/contaminated ATF and on some cars can even give symptoms of a misfire under load. Also have they checked the earth straps between engine and body? It still sounds like an air leak somewhere though. __________________ Cheers Dave Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........

Nov 11th, 2018, 08:53	#34
Peterquest New Member Last Online: Jun 22nd, 2022 16:39 Join Date: Nov 2017 Location: St Ives	Hunting on acceleration in a Volvo 740. The Volvo is now fixed. It was an ECU issue - it isn't reading the idle switch correctly and thinks the idle switch is on all the time. So the overrun cut off comes on at about 1500 revs and the revs die. Carelect diagnosed the issue when we sent over the unit and replaced part of the ECU. Thanks for efforts to help. Yours Peter

Sep 6th, 2018, 12:25	#32
Peterquest New Member Last Online: Jun 22nd, 2022 16:39 Join Date: Nov 2017 Location: St Ives	Thanks. The fuel is the same and Kings of Witcham put more in as part of their investigation so I guess it is reasonably full. It hunts without the car moving. It is an auto. It happens cold or warm.

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