Solutions for engine ping/knock?

[Archer]

What are the options to stop an engine from pinging/knocking?

One solution I've seen is adding a resistor in series to the AIT (air intake temperature) sensor which essentially makes the ECU think it is colder than what it really is, leading to more fuel being injected. But I also know that readings from the lambda sensor will check the air/fuel ratio and adjust the fuel injected, and after some time (for the ECU to learn the offset) will mitigate any changes from adding the resistor. But this apparently only happens in closed loop mode which only applies during idle and cruising. Open loop applies under acceleration or heavy load, and this bypasses any lambda sensor readings as this sensor is too slow or something. In which case the resistor would be doing its job. And pinging only occurs under acceleration/heavy load so it should be all good... Or not?

Any other solutions? Could it be a simple case of a faulty knock sensor? I must actually check if the diagnostic tools would be able to see predetonation

 

[Colin62]

Surely the correct way to prevent pinging is to advance the timing, not to just pump more fuel in?

I'd try the knock sensor first if I were you.

Edit - as pointed out by Bursty-dude lower down, the timing is meant to be retarded not advanced. Not quite as retarded as I am though

 

[Sinbad]

What car is it?

 

[Drifter]

What Octane fuel are you using?

 

[Archer]

Surely the correct way to prevent pinging is to advance the timing, not to just pump more fuel in?

I'd try the knock sensor first if I were you.

I have no clue if it will be possible to change the timing

What car is it?

Not a car Not even mine thank goodness, haha. Dad thinks his BMW R1200 is starting to ping

What Octane fuel are you using?

95, not like we can get anything else as far as I know

 

[Sinbad]

I have no clue if it will be possible to change the timing



Not a car Not even mine thank goodness, haha. Dad thinks his BMW R1200 is starting to ping



95, not like we can get anything else as far as I know

If it is, you need to get it sorted ASAP. But not by hacking away at temp sensors.
It could be a number of things - carbon buildup in the cylinder, wrong spark plug fitted, low fuel pressure, faulty MAF or O2 sensors, wrong timing for whatever reason (I don't know how that bike's ignition system works), overheating etc.

 

[Colin62]

I have no clue if it will be possible to change the timing

You can't. It is adjusted automatically by the ECU, based on the knock sensor output among others. As Sinbad says, have it checked. At least hook it up to the diagnostic system at BMW and see what fault codes it's throwing out.

 

[Archer]

I'll bully my dad into stopping by a dealership (or friend with a diagnostic machine)
I half suspect though that there will not be any errors - the bike is known to run very lean to meet emissions standards in Europe. Hence I'm looking for solutions ahead of time

 

[Beachless]

The easiest/safest thing to do is to raise the octane level of the fuel, you can buy some race fuel or add octane boosters or buy Toluene, Methanol, Xylene and mix your own booster. A few points above 98(which I assume he always uses) should make a world of difference.
You can maybe also check with BMW if they dont have an map update that runs a bit richer.

I would be quite surprised if the motor does not have knock sensors and retards the timing automatically though which should make pinging unlikely unless there is a issue somewhere.

 

[Archer]

You can maybe also check with BMW if they dont have an map update that runs a bit richer..

Oh there is an alternate fuel map, but in SA we are not allowed to get it for some arbitrary reason

 

[Bursty-dude]

Surely the correct way to prevent pinging is to advance the timing

No. When pinging is picked up by a knock sensor, ignition timing gets retarded, not advanced.


@Archer, the R 1200 GS and RS models have knock sensors. Tell your Dad to take it to a BM shop so they can do a diagnostic check on it. There are known cases where the knock sensors were faulty and replaced, and some cases of the pistons being poked, and also replaced under warranty.

 

[Colin62]

No. When pinging is picked up by a knock sensor, ignition timing gets retarded, not advanced.

Oops

Don't know what I was thinking when I wrote that....