Mazda 6 Forums UK

Technical Section => Troubleshooting => Topic started by: fergie on October 13, 2019, 06:03:58 pm

Title: 2006 Mazda 6 TS Hunting Engine
Post by: fergie on October 13, 2019, 06:03:58 pm

Hi everybody, Its my first time on here so forgive me if its in the wrong place or topic area. I need help with my 6 it has all of a sudden started hunting at idle and through the revs, It runs smooth and not rough but constantly hunts. I found a crushed pipe coming from the pcv valve which went back to its original shape when the engine was turned off so I replaced both the valve and the pipe but to no avail. There are no air leaks anywhere and no faults when connected to a reader. There are certain things I can do to make it stop hunting which includes restricting the airflow through the filter housing by putting my fingers in it across the intake just before the MAF and it runs lovely. This is obviously not a permanent fix and could be putting me along the wrong path Don't want to take to Mazda @ £114 p/hour to Diagnose only. It has been to two garages so far and nothing. Anybody had this or any advise would be very much appreciated.
Fergie

Title: Re: 2006 Mazda 6 TS Hunting Engine
Post by: apav on October 14, 2019, 03:58:15 pm

What does hunting mean?

Did you try to replace the MAF?

If you just bought the car with unknown history, there are so many things that can have been altered by the previous owner.

Title: Re: 2006 Mazda 6 TS Hunting Engine
Post by: fergie on October 15, 2019, 07:12:07 am

I'm sorry I thought the term "hunting" was understood to be when the revs go up and down at a pretty constant regular rate. Anyway yes I did try MAF which made no difference at all. The revs go up and down right through the rev range even when you accelerating.
I've had this car 4yrs and it has never been any trouble. It is standard and not be altered in anyway.
Fergie

Title: Re: 2006 Mazda 6 TS Hunting Engine
Post by: apav on October 15, 2019, 11:23:11 am

Have you tried to clean the throttle body?

https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-throttle-body

Title: Re: 2006 Mazda 6 TS Hunting Engine
Post by: fergie on October 16, 2019, 08:59:57 am

yes, Throttle body cleaned, vacuum pipes checked MAF sensor changed and still the idle is everywhere. Even when accelerating its up and down.Tick over is between 1500-1760 revs constantly fluctuating between both figures. Still have good acceleration but very unstable.
Fergie

Title: Re: 2006 Mazda 6 TS Hunting Engine
Post by: apav on October 16, 2019, 12:22:58 pm

The issue with the venting of the engine oil, sounded like you were doing very short trips and maybe the oil circulation system was not totally free. Have you tried to drive it for some long distance to clear it out? Do you keep up with regular oil changes?

These petrol engines rev high when they are cold. Are you sure that all sensors measuring the temperature are reading right? Maybe the car thinks that it is cold and so it injects lots of fuel which goes unburnt because the engine cannot burn it properly.

Have you ever replaced the spark plug wires? A dying coil pack can also affect your idle.

Title: Re: 2006 Mazda 6 TS Hunting Engine
Post by: fergie on October 17, 2019, 09:31:37 am

Thanks for the reply, the car is serviced every year without fail but does only do low mileage, sometimes only 4 miles a day for weeks on end before getting a good run.
You have certainly given me some ideas to think about.
many thanks
will let you know how I get on
Fergie