Polo 2008 1.4 BUD Auto misfire

[rasA4]

Hello
My Mrs has a Polo 2008 1.4 BUD Auto misfire on idle for a long while now, my friend has tried various things on the car new NGK spark plugs he also swapped out coil packs and a used lambda sensor made no difference whatsoever. just had the injectors tested still the same.
unfortunately i didn't have the time to deal with this in the past

Now have the time to get to the bottom of this issue I have bought VCDS no errors showing up any advise on anything would be grateful
I have checked the vacuum pipes all look fine.

Many Thanks.

[Crasher]

With VCDS, go into advanced measuring blocks and select misfire recognition, misfire counters and individual misfires then observe.What you describe sounds like worn exhaust valve guides.

[rasA4]

With VCDS, go into advanced measuring blocks and select misfire recognition, misfire counters and individual misfires then observe.What you describe sounds like worn exhaust valve guides.

Thanks for speedy reply not sure if i have select the correct options, note this was when the car was started and in idle
misfire screenshot 2.jpg

[Crasher]

Yes but it is disabled which could be it being cold or the rpm too high, wait for it to enable.

[rasA4]

Yes but it is disabled which could be it being cold or the rpm too high, wait for it to enable.

Hi again just been out to the car plugged in VCDS and let it run up until 90 i still get the same readings

I left the VCDS running and funny enough it changes to enable when the car is off

ill wait for your helpful advice just wondering if any of the parts that was changed could be faulty? not 100% sure as the fault is the same

[Crasher]

That could suggest a crank speed recognition error i.e. an unstable signal as the time between each pulse is used with the cam position sensor to calculate combustion speed and hence show i misfire, also display the rpm and coolant temp, you can show up to 12 different values. If you click on the graph mode you can view the RPM (well all) as a line graph which can help visually highlight changes. Quite often an unstable crank speed sender (caled a G28) does not register as a fault code, on yours they are a PITA to change, inlet manifold off.

[rasA4]

That could suggest a crank speed recognition error i.e. an unstable signal as the time between each pulse is used with the cam position sensor to calculate combustion speed and hence show i misfire, also display the rpm and coolant temp, you can show up to 12 different values. If you click on the graph mode you can view the RPM (well all) as a line graph which can help visually highlight changes. Quite often an unstable crank speed sender (caled a G28) does not register as a fault code, on yours they are a PITA to change, inlet manifold off.

Please find attached its quite a small picture hope you can see it ( i have a bigger picture not sure how i can display it bigger on here) i had a look to see the location on a diagram of the crank speed sensor couldnt find it, PITA i agree if its below the intake i was there last year when i had to change the crank case breather valve ( as the power steering fuse kept blowing)

btw this misfire has been there a long while before i changed that part.

graph.jpg

[Crasher]

It is in the back of the block pointing at the rear crank oil seal, eveil to do for what it is. That blip may prevent the misfire recognition from working which it clearly isn't.

[rasA4]

duplicate

[rasA4]

It is in the back of the block pointing at the rear crank oil seal, eveil to do for what it is. That blip may prevent the misfire recognition from working which it clearly isn't.

apologies 'eveil'? is that even?

Thanks not looking forward to taking the inlet off again but got to be done think I found the p/n 032906433 on my mates etka
will keep you posted
Many Thanks