Mazda 6 Forums UK

Technical Section => Troubleshooting => Topic started by: slidey on December 05, 2011, 01:21:29 pm

Title: running very rough
Post by: slidey on December 05, 2011, 01:21:29 pm
Well peeps my first problem with my diesel 6 143bhp, for a while i've had an issue with the tickover, with the clutch pushed in it's fine but when released it'll start running rough and getting very lumpy.The other week i took it for an MOT, it passed fine but the guy struggled to get any emission readings, while it was parked outside ticking over it started it usual trick but with a differance, alot more lumpy,hunting very badly, it would'nt respond to the throttle and lots of white smoke, i switched it off, went into pay, came back out and started the car up, it was a little rough but soon forward 2 weeks, i put some diesel in the tank and headed off down the motorway, only did a mile or so when it started with a bad misfire, very jerky and again it did'nt respond to the throttle, when it did there was a long lag and more misfiring, came off the motorway and limped the car home, still running very rough, bad diesel knock and nearly dies when you touch the throttle.
I've cleaned the airfilter(k&n),MAF, checked all the hoses,no diesel leaks, not using any oil or anti freeze and i've also replaced the suction control valve, this did'nt make any differance, maybe tickover is a little better.
Not much more i can do, so the local garage have collected the car this morning, i do know the have the right equipment to access the ecu and do any resets if needed.
I will report back when i know anything. Anybody on here had the same problem or have any ideas what may be going on?

Off to sulk
Title: Re: running very rough
Post by: Little John on December 06, 2011, 11:34:28 am
My guess would be that one of the sensors of some description is playing up.  I had what sounds like a very similar problem on my old Astra when the crankshaft sensor was playing up.
Title: Re: running very rough
Post by: slidey on December 07, 2011, 05:53:53 pm
Well i was part right with the SCV, the garage did a cracking job, did all the right checks,tested just about everything, turned out to be PETROL in the tank!!! i double checked the invoice from the station and it says DIESEL! the station admits "we've had some problems with the fuel supply and will cover the cost".After a chat with the garage i'm not the only one it seems, this has been ongoing for a while! so i won't be filling up there ever again, funny thing was i filled my motorbike up there the other week and that's been acting funny, after a dose of pro boost it's been fine, the pro boost helps the octane and gets rid of any water in the fuel.......does make you think.
Anyway the car is going better than it ever has done, i suspect all the cleaning they've done has helped along with the SCV. Well done GEP top job chaps.

Title: Re: running very rough
Post by: andyk3090 on December 08, 2011, 08:47:40 pm
I used to work for a company maintaining petrol forecourts in the UK. It would amaze you how often they get what is called a cross-over in the tanks. This is where the delivery tanker drops the wrong fuel into an underground tank. They always pay up  where they get multiple complaints to keep it quiet, as they don't want bad publicity.

The system at delivery point relies on the driver connecting the hoses from the tanker to the correct tank fill point. As these points are all the same fitting, it relies on the dirver being alert and connecting the hose to the right one. AS with human nature, mistakes get made...  :-\