Missfire problem with my Audi A4 1.8T with Fault Codes

[JIGGY C]

Hi I have a missfire from my car at Idle. When in motion all seems okay but when at idle the car shakes around (like the wind is hitting it) and the exhaust garbles along with the missfire.

It is stage one tuned with a Milltek Cat Back system, remap and carbonio. I've had the throttle body cleaned and reset and recently changed the diverter valve at the top of the engine due to the old one leaking/hissing.

The car has been in today and been serviced along with new plugs. The fault codes have been read and are as follows:

18062 – Please check DTC Memory of Instrument Cluster
P1654 – 004 – No signal / communication – Intermittent

(If it helps I recently took the ECU Fuse out by mistake!)

17544 Fuel Trim BANK 1 (Add) System too lean
P1136 – 001 – UPPER LIMIT EXCEEDED – MIL ON

16891 – IDLE CONTROL SYSTEM RPM – HIGHER THAN EXPECTED
P0507 – 001 – UPPER LIMIT EXCEEDED – INTERMITTENT

17705 – PRESSURE DROP BETWEEN TURBO AND THROTTLE VALVE (CHECK D.V.!)
P1297 – 001 – UPPER LIMIT EXCEEDED

16684 – RANDOM/MULTIPLE CYLINDER MISSFIRE DETECTED
P03000 – 008 – IMPLAUSABLE SIGNAL

16685 – CYLINDER 1 – MISSFIRE DETECTED
P0301 – 008 – IMPLAUSABLE SIGNAL

16686 – CYLINDER 2 – MISSFIRE DETECTED
P0302 – 008 – IMPLAISABLE SIGNAL

Also, the CAT does appear to glow quite a bit!

I only use 99ron super unleaded fuel.

Any advice or suggestions would be most welcome!

[blackpool1974]

Hello my friend,

You have the classic crankcase breather valve problem.

Its a valve that is inside a T piece pipe near your oil filter/under manifold

Basically your car is running lean at idle when you stop, a valve doesnt close and your engine is flooded with air, and not enough fuel, hence jerking, also because of this problem it will have broken your Pressure regulating valve (PRV) black disc at the back of the engine (£25) that is causing the pressure drop between the turbo and throttle valve, I went through 3 or 4 of these whilst I had the problem


http://www.ecstuning.com/Search/Cran..._Valve/ES5957/



http://www.ecstuning.com/Search/Cran...alve/ES258895/

Do a search on crankcase breather valve and you will find a thread I made a while back


Took me over 6 months and £600 to fix it, if I had known the fault straight away looking at £50 all in, aslong as you dont break any of the brittle rubber pipes attached to the breather valve, might be an idea to change them aswell



Audi charged me £280 robbing feckers

PRV £25
Breather valve £20
New clips etc etc £5

What is my reward

[JIGGY C]

Fantastic and much much appreciated reply - thank you.

Is the breather pipe the one in the photo below that I have attached - it sits more or less just above the oil filter?

I have also attached a photo of the diverter valve that I recently replaced - is this the same one you mentioned as well?

Many thanks - I come to Blackpool quite a bit - I bought the car from Preston just up the road so if your still living that way I will return the favour with beer tokens!!

Hello my friend,

You have the classic crankcase breather valve problem.

Its a valve that is inside a T piece pipe near your oil filter/under manifold

Basically your car is running lean at idle when you stop, a valve doesnt close and your engine is flooded with air, and not enough fuel, hence jerking, also because of this problem it will have broken your Pressure regulating valve (PRV) black disc at the back of the engine (£25) that is causing the pressure drop between the turbo and throttle valve, I went through 3 or 4 of these whilst I had the problem


http://www.ecstuning.com/Search/Cran..._Valve/ES5957/



http://www.ecstuning.com/Search/Cran...alve/ES258895/

Do a search on crankcase breather valve and you will find a thread I made a while back


Took me over 6 months and £600 to fix it, if I had known the fault straight away looking at £50 all in, aslong as you dont break any of the brittle rubber pipes attached to the breather valve, might be an idea to change them aswell



Audi charged me £280 robbing feckers

PRV £25
Breather valve £20
New clips etc etc £5

What is my reward

[blackpool1974]

Yes the 1st picture I posted is the actual valve and then the other is what it sits in

The 3rd picture of the ones you posted is the spaceship shaped "Pressure Regulating Valve" that causes the pressure drop between turbo and throttle valve.

As for the actual location of the valve I haven't really looked for it, was just told that is where it was after I queried the £175 labour cost from Audi

The diverter valve if I am correct is below the PRV and has nothing to do with your problem as you should still be keeping Turbo boost as your problem is only when your car is at idle

Keep me updated.

[JIGGY C]

Update - SORTED!!!

Big shout to Balckpool1974 - without you I would not have solved this, nor would my garage and nor would my wallet!

I located the valve (hidden inside the t-junction pipe beneath the intake manifold) and after some effort getting between al the other hoses and pipes (thank god I have skinny wrist's!) I manage to remove the old one and fit the new one. The car now runs as though it is brand new and is certainly a lot quicker!

The old one had broken. The flap inside had collapsed and basically remained open at all times from when I can see. I took a photo of the old and new next to each other to help anyone else in the future as below.

If you decide to do this repair yourself the Part Number is 035 103 245 G and is currently £6.70 + VAT. If you are off a big build I will say that there is not much room to do this job - you really have to get between a lot of pipes and hoses all very close together in a small space without much sight of the object - you can remove the other hoses but this will all take a long time. Make sure you allow your engine a few hours to cool down as well.

Again a BIG THANK YOU to BLACKPOOL 1974!!

PS. How do you find your Smart Roof? I'm thinking off doing this to mine?!

[blackpool1974]

I went to 5 different garages, replaced all my vacuum pipes and Maf.

After spending £400 decided to try Audi, Master Technician knew as soon as soon as I mentioned the symptoms, £275 later fixed.

I just wish there was somebody like me then !! I searched for months

[vw j turbo]

Thank god for this thread

[fla]

i too replaced this on my car recently. As mentioned, a bit fiddly to access - the jubilee clip bolt head was at an awkward angle making it very difficult to open. In fact this took the most time. Once off, the valve just pulled out, fitted the new one (mine also showed the same break in the valve) using a bit of washing up liquid, new jubilee clip and idle is now back to normal. That said the emissions light has just come on again, although this may be an old code, so will delete and rescan.

[Gordon804]

Hi, just had the same problem on my 2004 Audi A4 1.8T. Looks like a very common problem, here are the part numbers for changing the breather hose and valve for future forum browsers....

V035 103 245 G - valve
V06A 103 213 F - breathertube
VN 907 399 01 - clip
VN 904 673 01 - o ring
V037 121 142 A - retaining spring
VN 024 520 3 - clip

https://www.vwaudiforum.co.uk/forum/s...t.php?p=736272

[turpal]

Good to know that,cheers guys.