Technical advice on mis fire on 2.0 tfsi engine!!!

[Monkeymagic]

I don't have access or experience of leak down tests I'm afraid. I'll try the long screwdriver method I guess.
Let's hope it's as simple as a knacked PCV as it 4 screws... I must be getting lazy.
Keep the suggestions and experience coming it all helps. Ta ste

[stocious]

It's not a diesel it's a petrol. I share your frustration though.
I spent 3 weeks recently chasing a hot mis fire on an Alfa brera 2.4 5 cylinder diesel. 2 injectors were leaking so I was positive it was an injector issue. No faults logged just a very rough idle on tick over only when hot.
I pulled all injectors had them checked an cleaned all clear. Took it to an Alfa specialist who blamed the dpf and charged a fortune for forced regen. Guess what it wasnt that.
In the end after watching various readings on lap top. I found the egr was staying open. Intake cleaned and egr replaced and it was back to pull health.
I was close to giving up with it, but I hate quitting. Swore I'll not work on another Alfa. Til next time!

i knew it was petrol, i was just saying if a diesel it would be my first place to look, i should have been more clear

but im with you all the way with the stress a miss can put you under, all to well.
still have a place in my heart for dizzy's.

this renault in question, when you start unpluging coils to hear change, it also drops the companion coil too.. got the heads up from a renault tech and he advised to change in pairs. 1 and 3 or 2 and 4 if you suspect a dead coil..

turned out to be the injector in that case but the coil fiasco is a thing that could cause alot of bother to someone who didnt know... ME lol

[Monkeymagic]

Sorry bud. They say every day is a school day. Let's hope I learn more about this engine soon.!
I start ranting about French cars pretty quickly. Mind you had a few words about Italian cars last week Sheer frustration on my behalf.
I often wonder why I take the jobs on its only really meant to be a hobby.

[stocious]

leaning every day, well i hope so lol.. anycance hes sticking tenners in here here and there and is now after finding some goodies at the end of the tank.
convinced thats what caused the injector to fail in my case.

bet of luck with it man.. tomorrow is another day

[Monkeymagic]

If I find the cause I will report back.

[DJones]

My Mrs has one, touch wood never had a problem with misfires.

I did have to change the PCV and dump valve though. When the PCV had gone the effect was a higher than normal tick over and massive vacume in the engine making it really hard to remove the oil cap.

Remove the cap with the engine running and put the palm of your hand over the hole you will know if its not right but I don't think it will be the cause of your misfire..

Hope it helps

Darren.

[Monkeymagic]

i haven't noticed any vacuum or pressure. i haven't removed the cap with the engine running though.
i removed the Pcv valve and could blow through it but not suck etc. however i cannot re create the pressure of an engine. they are a main reason for the under boost code so worth a shot.

[DJones]

i haven't noticed any vacuum or pressure. i haven't removed the cap with the engine running though.
i removed the Pcv valve and could blow through it but not suck etc. however i cannot re create the pressure of an engine. they are a main reason for the under boost code so worth a shot.

I did the PCV first which sorted out the idle speed but it was still under boosting, turned out the DV diaphragm had split too, which fixed the boost. Neither of this problems caused a misfire though....

Darren.

[Monkeymagic]

im not that optimistic i have to say. I still wonder if there is an issure with the MAP or suspected map as we are not sure.
I have read a fair bit about these cars not taking too well to MAPS. Not sure about that though.

[ManiacuV6]

Try to put the original software and after that to check the car. Sometimes it helps .

[Monkeymagic]

yeah i think he needs to find out for certain if it is mapped. and then return it to its original state if it is.

[ManiacuV6]

If you make a log you can figure it out very easily if is remaped or not .

[Monkeymagic]

Well I have replaced the intake pipe and pcv. I drove it around for 100 miles or so and the 00665 code returns when I bury my foot in higher gears. In other words under full load. It was still counting the odd misfire in measuring blocks but they would clear themselves. It does not log it as a fault as yet???
I went to take the inlet off today and despite being free it would not pull loose. I suspect it was the injector seals but didn't want to keep pulling as I risks damaging something.
I did clean the map sensor on the inlet manifold as I read these being covered in oil can cause under boost code. I also reseated an intercooler hose that was not sat well.
I drove it home and tried to re create the under boost code without success.
I couldn't figure out how to create a log but logged the actual boost to specified boost. On tick over the spec should be 250mbar but the actual was 850 Mbar. At partial throttle it was somewhere near spec. Then at wot it was under reading???
What the hell is going on??? Someone been messing somewhere maybe.
I think I've done all I can do for him. Got enough of my own stuff to be getting on with. Ha ha.

[Monkeymagic]

just did another log. hee hee. no seriously.
when its at idle or partial throttle the n75 duty cycle is 0%
at half throttle the n75 gives maybe 18%?
then at wide open throttle when the boost drops below spec its a 95%
i think Im out my depth as Im not certain what's normal.
does this mean n 75 isn't opening when it should and opening too much when it shouldn't!
help.

[Monkeymagic]

been looking at the log file. i have it from reliable source that max boost on this engine would be 1700 mbar. the actual boost plot is pretty consistent. the requested is all over the shop.
the max actual boost i have seen is 1960 mbar. pretty healthy is stock is 1700.
however ecu is requesting 2250mbar .
would this suggest this thing is mapped.