[Mk2] [Turbo] Knock sensor 52 error code

[alan wheeldon]

What would cause an error code 52 knock sensor. Could it be too much boost?

My Rev2 turbo engine was rebuilt 5000 miles ago and is a standard rebuild with the usual breathing mods and the boost is upto 1.1bar.

Not had a problem really up until I went to Silverstone to do a track day. Since then this code has been on but after a reset has gone away. What could have caused this so I can avoid it happening again in the future. Do I simply need to turn the boost back down

[aw11rally]

I had an intake pipe split between the AFM and the turbo. This let extra, unmetered air into the engine. The check engine light would come on as soon as the engine came on boost. It also tripped the code 52 due to excessive knock (running too lean). I fixed the pipe and reset the ECU but still had an intermittent fault showing code 52.

It turned out that the knock sensor was knackered, apparently quite common, especially after an episode of excessive knock.

A new sensor solved the problem.

I'd try to rule out any issues that may cause knock before changing the sensor, it is there to protect the engine after all.

Also are you using high octane fuel such as tesco 99 etc, 1.1bar may be a bit much for normal 95RON depending on intake temps etc.

[alan wheeldon]

I use Vpower and also when i was on track apparently it was spitting out flames quite regularly which says to me it's using too much fuel so the air/fuel ratio doesn't sound right? Don't know how to change that though??

Also I replaced the knock sensor last year as it went faulty bug I used a second Han one as there a tad expensive new!

[alan wheeldon]

Ok from what I can gather it is running lean due to a mixture of too much boost, too high an air/fuel mixture or the timing is too advanced. These are the symptoms of knock so I either need to

Reduce the boost pressure

Buy an adjustable fuel pressure regulator and lower the ratio

Does this sound about right??

[bobhatton]

Ok from what I can gather it is running lean due to a mixture of too much boost, too high an air/fuel mixture or the timing is too advanced. These are the symptoms of knock so I either need to

Reduce the boost pressure

Buy an adjustable fuel pressure regulator and lower the ratio

Does this sound about right??

It has been shown that the stock engine will run off the knock sensor even on standard boost and the best fuel.
So lower the boost and set the timing to 8 deg BTDC.

You also need a new knock sensor when you get that code

[alan wheeldon]

Is the sensor the same from a turbo and a NA?

[bobhatton]

A 3SGTE one should be the same as a 3SGE one but the plugs do change depending on the year.

[alan wheeldon]

A new sensor has fixed the problem but I have turned the boost down to 12psi as a precaution. It's slow now though! Lol