Has anyone ever heard of, or experienced, a problem with a Knocklink that causes it to start lighting more LEDs than usual?

I have mine set to max sensitivity (as everyone does - right?), and it used to be virtually silent, but has recently started lighting up as though the engine is knocking badly on boost. I thought it was a bad batch of fuel, but it's still doing it with a fresh tank of Optimax + OB. So, unless a bad tank of fuel persists for a long time, there's something wrong with the KL, the engine or the ECU.

It's booked in to be looked at anyway, but it seems odd that a brand new engine (3700 miles) should suddenly start misbehaving. Car is an '05 JDM STI with a very mild map for UK fuel.

 

Do you think the milder weather has brought on a mapping issue?

How long have you been on the new engine?

 

It was a brand new car in October last year, and there are loads of identical cars out there that I know are on the same map. It's been showing lights even in freezing conditions, so I don't think that's it

 

Andy,

Sorry if this is a dumb suggestion, but is there a chance the sensor could have become dislodged/damaged and is now picking up background noise or providing false readings? Unless the fuel was badly contaminated, it shouldn't be causing knock for that long.

Regards.

 

I've heard stories of Optimax 'going off' and degrading to 95RON!!!

That said, what octane booster are you using and how much?

The only time (other than on a RR at the upper end of the rev range) I had my Knocklink light more than the bottom LED was when I used BP SUL instead of the Optimax it was mapped for! It was obviously an octane thing, as I stuck in a cap of NF OB and it was back to normal!

The only other thing I can think off, is that the cold spell recently is setting it off.

And yes maximum sensitivity on the KL.

 

Having partially emptied and refilled the tank a few times, I worked out that what's in there now is:

2.5 litres suspect fuel
6.5 litres super unleaded
51 litres optimax
1 full bottle plus the remains of a previous bottle Millers octane booster

The car's been remapped and was previously quite happy on any brand of SUL. The octane booster should be unnecessary - and given that filling up with optimax plus OB didn't seem to make any difference, that's why I'm now beginning to wonder whether maybe it's something else.

ps. have checked the sensor, the bolt seems tight - though it's actually a complete pain to get to as the dipstick and a/c compressor get in the way of any spanner or socket

 

Andy

Are you getting continuous amber or red, or just a spike? What revs is it appearing at? The new age cars are most vulnerable to det betweeen 5000 and 6000 rpm, especially around 6000 rpm.

I had a det spike on my UK 02 Sti with max KL sensitivity, which PE said was normal and due to the ecu running on the edge of det and then pulling the timing when it detected the det. Octane booster made no difference to the KL activity. I had a word with Bob Rawle about this and he said it was probably OK but shouldn't really do it. In the end I got Bob to remap it which he does on the road rather than on rollers (different engine load characteristics). He also directly measures the output from the lambda probe and listens with det cans. Det cans are the only accurate way of confirming the KL activity. My car now feels much quicker and is running more boost (1.55 bar). After Bob's remap I did still get the occasional det spike, but since Bob advised me to turn the KL sensitivity to the 2 o'clock position it has been fine.

Whoever you get to look at your car, make sure they use det cans. If you are getting more than a spike on KL then I would start to worry. You could email Bob Rawle since he has the same car as you and therefore relevant experience. He was most helpful to me, even before I committed to his remap. He even encouraged me to first go back to PE rather than use himself.

Hope this helps.

Alan

 

Thanks Alan. The car's going back to Powerstation for an on-road session with a laptop and det cans next week. I'm getting one or even two flickering amber lights around 5000rpm on WOT - not something I'm prepared to investigate much further on a brand new car that was perfectly fine until recently. I did also see one red spike on lift-off, but I couldn't reproduce it (and, frankly, didn't really want to either!).

 

Andy, I'm having the same problem on my 04sti. KL lights up like a xmas tree. I've been told to turn the sensitivity down but doesn't that defeat the object???

 

Absolutely, yes

I'll let you know how I get on at Powerstation, I'm hoping they just have to drain the tank and fill up with a quality fuel. Did yours work OK and then suddenly start misbehaving?

 

I had the knocklink fitted after the re-map.
I'll send you a pm.

 

This doesn't sound like the correction location for the sensor. Mine is quite easy to get at with a normal spanner. Standing on near side of engine bay reach down underneath intercooler and to left (towards front of car) and sensor should be mounted on the front of the block in a exsting threaded hole. I don't remember going near the dipstick!

Alan

 

I think there's more than one possible location for the sensor, though - isn't there?

Either way, it doesn't change the fact that it used to work OK, and now doesn't. Something changed. I'll know more when it's been in for diagnostics next week.

 

This will give you some idea where the KL sensor is best located.