car not well

disley

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Recently i noticed the s4 missfiring/hesitating, on cold start, only for first 30 secs, give it a couple of revs and off she goes.
So i took it to me mates garage so he could plug it in
Came up with 2 codes
1128 fuel preasure, inlet leak air system, hose leak
1130 same description
So he reset the codes and then when we run car it has a constant missfire
Disconnected the MAF while running and missfire dissapears, also driving without MAF connected it pulls much stronger
So as all the garages are shut I will have to wait till monday morning to get it sorted,
I take it the new MAF should do the trick, should i check anything else
 
agree do a pressure check

have you ever replaced any of the know culprits in this space? i.e. tbb, f-hose
 
If there's unmetered air being drawn in, disconnecting the MAF will make it run better.

The MAF may not be faulty, check for leaks and splits, before condemning it.

Best of luck.
 
Done a pressure test today to check for leaks
didnt find any leaks on the intake system
Diverter valves seem ok
the only thing i could hear was air hissing down the side of the camshaft adjustment valve on the front passenger side of the engine,
couldnt see the exact location the air was comming from but dont think this is part of the intake system anyway(Im probably wrong) but i thought this was due to air getting through to the engine and into the cam area
If I take the oil cap off the pressure is released
Or am I doing something wrong?
 
i _THINK_ the crank case breathers would allow air from the inlet to flow into the crankcase then up and out the oil filler...
 
If the crankcase is getting pressurised then chances are that one of your one-way valves is shot. There are three I think, two green, one grey. You can see them under your Y-pipe.

Don't cost much to replace, and there have been a few S4's where these have started to fail now, mine included.
 
I will check the 1 way valves, thanks for that
makes it a bit awkward with them silly one use jubly clips
 
Pinched from www.RS246.com:
S4 (from RS246) said:
there are 2 green ones 078 905 291B and the grey one on top of the Fhose 035 103 245A, don't be fooled by the grey one, I have tested 3 of these, new and old, and you CAN get a little bit of air through them, I though I had a faulty 035 103 245A so I purchased a new one and tested it before I fitted it, you can blow through it just a tiny bit, and that is normal........ the green ones you cant. also Injector O rings can leak.

Darren
 
After doing a few checks on the usual suspects and not coming up with anything, I decided to go ahead with a new MAF and put it on today.
BINGO!!
Car now feels like an s4 again, much stronger acceleration than before,
Must have been on its way out for a while just that I didnt realy feel the gradual reduction in power.

A BIG Thanks to everyone for their input, Much appreciated
:respekt:
 

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