Would a faulty knock sensor cause fueling problems?

[efil4sbuD 0]

I have been having an intermittent problem with fueling on my VR6.

 

Usually it happens at around 1800 revs and without any change on the throttle pedal the car loses power and begins slowing down. If I stab the throttle it seems to wake it up and it drives as it should.

 

I thought it could be a faulty throttle position sensor. If I understand this correctly, the TPS signals are only used at part throttle and at WOT, the signal is ignored. This would help explain why the car might drive normally after stabbing the throttle.

 

However, upon stripping the front of the engine down to replace a crack pipe I noticed that the inlet manifold running to the forward bank of cylinders was quite black inside whereas the rear inlets where relatively clean. I then noticed that the knock sensor under the crack pipe was cracked and so I'm wondering if this is to blame for my strange loss of power and is somehow leading to an over/under fueling problem on the forward three cylinders.

Or (I just thought of this), it's causing the ECU to alter the firing time so that combustion is taking place whilst the valves are still open hence the black intakes and loss of power. I'd like to think I've just answered this myself but does anyone else have an educated view of this?

 

 

For information; I have swapped the MAF for a known good one and it made no difference.

[efil4sbuD 0]

Any ideas anyone?

[Yandards 0]

A knock will cause the ECU to pull back timing but it should only be on a single cylinder and not an entire bank.

 

Have you put it on VAG-COM to see if it sees any faults?

[VR6Pete 0]

when your knock sensors kick in, it retards the map, loosing power..... usually if you have problems you would hear a 'pinging' noise too...

 

I'm pretty sure if you have a faulty knock sensor it will show on VAG COM, so id personally scan for fault codes first...

Edited March 6, 2012 by VR6Pete

[efil4sbuD 0]

I haven't scanned it yet. I have a cable but I need to get VAG COM back on the laptop. I could do that now I suppose.

 

Reference the pinging noises, the only time it happens is when I'm driving so I doubt it would be loud enough to hear over the road noise etc.

 

---------- Post added at 3:53 PM ---------- Previous post was at 3:23 PM ----------

 

 

Wouldn't the knock sensor cause the whole bank to retard if it was cracked and broken - which it is - thereby giving a dodgy signal not just during one cylinder firing but for a few seconds at a time?