1.8 Stalling

[christopherb1981]

Hi

Hope you can help! My mazda 6 1.8 ts on a 56 plates keeps stalling. When you come to a stop the engine dies but it does not do this every time. Idle is a little lumpy but not to bad. Problem is slowly getting worse. At time when it cuts out it will be a little lumpy for awhile when driving. Taken the car to mazda main dealer twice. First vist they told me to take the car for an hour long journey to reprogramme the fuel ecu. That did not work so took it back today. They told me no fault codes but it could be an oxygen sensor, that want nearly £500 and it might not it fix it! Is there anything common on these? Don`t like having a car that cuts out with a 2 year old and an 6 months pregnant wife who mainly drives it  .

Thanks

Chris

[slidey]

I would be very tempted to clean the throttle body, it gets gummed up and can cause the car to stall, i use brake cleaner and a rag.

Dave

[DavidN]

Hi Chris - Can't help with an immediate solution - but just a thought. As it's a standard 1800 petrol I would think a good independant garage might solve your problem with a little more concern at a much cheaper rate? Try the website Good Garage Scheme -  maybe you can find a more appropriate home for your hard earned cash David.

[bazzamf]

I would try what "slidey" suggests first. It's a relatively easy fix and may resolve the problem. The throttle body is located at the end of the throttle cable towards the front of the engine. It houses the butterfly valve and its the body, this valve seats and moves in, that requires the cleaning. Over time, the housing gets a coating of a lacquer type material which needs to be cleaned off. It can also make the butterfly valve stick, which is a problem I had with my previous 6. I think you can by a special cleaner in Halfords.

[Steve_c]

I don't know if it's a similar setup, but the petrol Vectras had an idle control valve on the side of the throttle body which would get caked in recirculated oil mist.  Over time, this would cause it to stick in the closed position and cause the engine to die when approaching junctions - a very common problem on the Vectras.  Removing it and giving it a good clean with carb cleaner seemed to do the trick.

[john white]

My Mazda 6 tends to stall when I stop at a junction when first starting out when the engine is still cold, have just replaced battery and have removed and cleaned the EGR valve, have had a look at the throttle body but looks difficult to access from top of engine bay. My Mazda is a 2003 2ltr diesel with 140,000 miles on the clock.....

[SM25T]

Throttle pot/IACV (idle air control valve) is easily accessible on the 1.8 petrol. Remove it and give it a good clean with carb cleaner. Unplug the electrical connector and drip a little WD40 or similar on the connectors before plugging back together.

Where are you based ?

[john white]

Thanks SM25T, my Mazda 6 is a 2ltr Diesel and the throttle body looks low down and difficult to access, will try and take a photo of it and re post.

Would WD40 on the connectors for the EGR Valve for instance also help during the winter/cold mornings. I am on the road around 4.45am each morning so will start getting damp/cold in the mornings again.

[slidey]

John, the common issue with the 2.0l diesel stalling is the suction control valve (SCV)going faulty, the valve is mounted on the side of the supply pump,that's at the front of the engine on the drivers side.
Genuine Denso ones cost around £120 on ebay, very easy to fit, just 2 allen bolts.
I would first check for any vac leaks or broken hoses,clean the MAF and check the air filter is fine.

Dave

[blueboy82]

I think there is merit to getting the tb cleaned  but all this does will improve the flow of air into the intake manifold wont resolve nowt else look at getting your maf sensor cleaned in my opinion the oxy sensor and the maf are sensors that tell ecu how much fuel to put in if they are dirty this can affect the cars fuel air mixture also look at if its not been done already look at pending codes on a scan gauge these can tell you where to look and whats about to go faulty

[john white]

John, the common issue with the 2.0l diesel stalling is the suction control valve (SCV)going faulty, the valve is mounted on the side of the supply pump,that's at the front of the engine on the drivers side.
Genuine Denso ones cost around £120 on ebay, very easy to fit, just 2 allen bolts.
I would first check for any vac leaks or broken hoses,clean the MAF and check the air filter is fine.

Dave

Thanks, have checked hoses best I can and also have cleaned the maf, and fitted a new air filter, so could therefore possibly be the scv ......

[john white]

I think there is merit to getting the tb cleaned  but all this does will improve the flow of air into the intake manifold wont resolve nowt else look at getting your maf sensor cleaned in my opinion the oxy sensor and the maf are sensors that tell ecu how much fuel to put in if they are dirty this can affect the cars fuel air mixture also look at if its not been done already look at pending codes on a scan gauge these can tell you where to look and whats about to go faulty

Cheers, I have a lead to connect to my laptop to read the codes so will have a look during the week.................

[john white]

About to change SCV this week so fingers crossed.

 However just to add to this I have noticed that when the engine is cold stalling occurs more often when I apply the brakes harder at the last moment, as apposed to decelerate gently when approaching junction/stopping .