Misfiring Vw Golf Mk4 Help!

[Crasher]

A fault code read will give us a clue but not necessarily a solution as it is most likely to be a lambda sensor code due to the poor running but equally you could get a coolant temp sender fault code which would explain the poor idle stability.

[rickrobbo]

Hi, believe it or not I have a Golf1.8T that has a mis ifre problem. It's been doing it for ages now. It is exactly the same, it miss fires for the first 2 mins of driving and the when the revs settle it's fine just the occasional misfire in low gears. Done loads to try and solve the problem - new cat, new lambda sensors, had to replace a coil pack. Just about given up on it now. If you solve the problem than let me know!!!!

[rickrobbo]

Hi, believe it or not I have a Golf1.8T that has a mis ifre problem. It's been doing it for ages now. It is exactly the same, it miss fires for the first 2 mins of driving and the when the revs settle it's fine just the occasional misfire in low gears. Done loads to try and solve the problem - new cat, new lambda sensors, had to replace a coil pack. Just about given up on it now. If you solve the problem than let me know!!!!

[Shleng]

Cheers for the diagrams and stuff Crasher. Shame to say that i aint solved the mystery yet! I have checked the fuse that you mentioned but it is fine. I have had a look at the valve behind the black bracket at the front of the block. Would the N249 solenoid valve be the item with the brass plate on it? I believe the item number is 026 906 283 h apg. I looked for obvious damage but none was present. What i did find was that the black bracket that the dipstick and the valve is seated was bent. After looking around the engine bay, it looks like the car has at some time had a front end smash! Could this shed any light?!

[Crasher]

Re-brief me on what is happening now and what codes you are getting.

[Shleng]

ill try and download the faults 2nite if i can and post em again. cheers

[Shleng]

I have not had a chance to check the codes but as i am still driving the car i have noticed today that the turbo seems to make a 'ripple'ing noise when the turbo is spooling down. It has either happened today or has become more apparant. Im assuming that i should be able to hear the turbo spooling down when changing gear but why would it make a noise like this? To put it another way, it sounds like blowing into a slow fan as it is facing you (if you ever have?!?!?) Im thinkin that it should be more of a constant quiet 'whoosh'. Am i wrong? I have not got an atmospheric diverter valve fitted, and have tried changing the standard Bosch one recently. Should i be worried?

[Crasher]

You should hear a slight hiss under boost and a small whoosh from a standard DV and that’s about it.

[Shleng]

finally got round to it crasher, got mainly the same codes but fewer this time;

17608 - Boost Pressure Control Valve (N249): Mechanical Malfunction : P1200
16795 - Secondary Air Injection System (B2) - Incorrect Flow
or Secondary Air Injection System: Incorrect Flow Detected : P0411
16684 - Random Misfire Detected - Any Cylinder
or Random/Multiple Cylinder Misfire Detected : P0300 - intermittent
16688 - Cylinder #4 - Misfire Detected
or Cylinder 4 Misfire Detected : P0304 - intermittent
16685 - Cylinder #1 - Misfire Detected
or Cylinder 1 Misfire Detected : P0301 - intermittent
16687 - Cylinder #3 - Misfire Detected
or Cylinder 3 Misfire Detected : P0303 - intermittent
17956 - Boost Pressure Regulation Valve (N75): Open Circuit : P1548
16686 - Cylinder #2 - Misfire Detected
or Cylinder 2 Misfire Detected : P0302 - intermittent
16705 - Engine Speed Sensor (G28): Implausible Signal : P0321

Still keeps mentioning about the N249 valve mechanically malfunctioning! i think i have the part number for this; 026 906 283 h apg
is this right? i may have got the wrong part but this was on the brass coloured valve at the front of the engine block (AUM) behind the black pannel that supports the dipstick.
thanks

[Crasher]

Sounds to me like a simple case of the small diameter hose from the “T” piece one way valve on the crankcase ventilation pipe to the inlet manifold being split. This can cause all the fault codes shown and a hissing under boost.