Hi all, had a misfire/rough running on my vehicle for ages and still cant clear it, basically it runs rich and uses loads of fuel and feels like theres a cly down or misfiring. this doesnt happen all the time but when it does it noticable. when its happening the revs sit where they should at the 850rpm area but when the engine is running smooth and fine the revs are at 1100rpm?? (why would the revs go higher?) this is what ive replaced and done and its made a little difference but not a lot.

 

Replaced

 

Both O2 sensors

Temp Sensor + Plug

Hot idle Valve

One Coil Pack

 

Checked/repaired

 

All boost leaks

cleaned throttle bodies

Been set up by Z world

Compression Check

Cleaned Idle valve

Cleaned Injector + Coil Connectors

 

Any more ideas lol

 

completely standard except for air filter

 

Regards Andy

Edited August 8, 200916 yr by andymeeson
more added

Ptu?

maf sensor?

What air filter are you using? If its a HKS foam filter, then could be the foam breaking up and sticking to the maf.

 

Al.

sounds like the maf mate. maf failures are all to common :(

sorry to jump on but yassa your inbox is maxed out.

just emptied it :rofl:

You say it is over-fuelling, have you had your 300 on a conzult to confirm this?

 

Al.

ive got hks filter maf sensor went with me misfire got worse until clutch blew trying to get any power by dipping clutch as its thinner than a human hair and burns contiminates off wire as you turn off engine ive been told with after market air filters its common to fail

thanks all for your replys, tried a known good maf didnt change nothing,(got an apexi filter) had it set up by zedworld so know thats ok. just confused now with the over fueling, also the vehicle does 0-60mph in about 7secs!! but boosts fine?

To me, it sounds like an elecrtical fault, either bad connections at the coilpacks, injectors, cas, ptu, or breakdown in the loom. It is a hard fault too find, but, keep trying matey, you will get there. Over-fueling will not cause the issues you have stated. My 300 is over-fueling and the rear bumper is covered in black spots after every drive, is yours? I may be wrong, but in the past, i have not.

HTH and ATB,

 

Al.

Edited August 11, 200916 yr by AlanZ

exhausts am but not the bumper lol ill check the cas connector, the only thing i havent cleaned yet lol

you havent said youve cleaned the PTU.

 

that is the usual culprit.

 

 

caused mine to stink of petrol then flood and not start.

 

 

remove it & scrape the green gunk off each end

UPDATE!

 

Been out this morning and cleaned every connector in sight, ptu,cas,idle control plugs,coils,inj's etc etc. car started and ran crap for 5secs sitting at 850rpm then seemed to clear. had misfire at 2500rpms and below but above nice and clear. left to get warm and engine now sits at 1100rpm!!! but runs really nice. took her for a drive and its flat as a pancake but no misfire! feels like a turbo theif has stolen them lol cant feel the turbos kick in like it used to? any reason for this and still doing 0-60 in about 7secs????

 

Please Help

 

Regards Andy

possibly timing

had timing belt done at Zedworld about a year ago and only just been set up aswell by Zedworld.

How did you check for boost leaks

i got a plug with a tyre valve in, took it to work and used the air compressor. should you blank anything else off when doing it? of just blow in via the air intake?

anything else to check?

i would firstly like to aske have you or anyone touched or srayed anything just before the problem? if not i would go back to the maf.unplug the battery for over an hour and clean the sensor inside the maf inside because this little tiny area can get grit dirt or oil or silcon on and affect the the air flow reading thus the ecu is trying to match the infomation with the chip sensor in the maff causing any and all sorts of stuff ,like eregula idal flat spots to even running like on 5 cyinders to no boost and then clen the connction as well all with no product that cotains silicon and is fee of any dust debree or pooh then reconect bat to reset ecu and try.but thats my own opinoin oh yes there might be some or alot of spelling mistakes buy hopefully its eleigable enough to read.hope this helps.

If your cars lost its mojo mate,chances are since you cleaned the connectors one is not readable by the ecu causing safety boost.Check your ecu codes.

cheers lads for the replies, cleaned the maf sensor but didnt reset the ecu. it defo lost its mojo, when sitting in park and floor it seems slow up till 3500rpms then flies.. boosts on stock guage about 13psi. didnt check fault codes after cleaning will do when i get five. thanks again lads

right lol my diary continues. checked tps voltage this morning and is at 0.46v with ign on. full open its 3.78v. Theres a little vaccuum box in front of the battery with a white plug going to it. if this is disconnected while vehicle is running would it make any difference? i removed it to clean while running and the engine never changed at all! thought this controlled the damper on the top of the engine?

also no fault codes, cleaned maf again, disconnected battery over night still the same?? vehicle getting very hot and when exiting the vehicle you can feel the heat from the exhausts and see the heat vapor!! and this is at idle?