markwild

I'm getting something a bit strange from my Knocklink since I remapped at PE. At 90mph in top (3.5k revs), off boost (i.e. cruising speed) I get the first green light flickering.

To maintain 90 on the level obviously takes a small amount of throttle - If I release that throttle, or increase it for a small incline in the road the light goes out -

I can't decide if its a faulty reading or whether the fuel mixture may be slightly lean at that point, with that throttle opening, causing slight det.

To be honest, I've now started to either slow slightly or go faster (!) if the light starts to flash, as this removes it..

Any ideas - or should I stop worrying -

PS _ I have a Dawes AFR, so it doesn't give me a reading at such a small amount of throttle.

Thanks,

Mark

Engine Wise - 98 Uk Turbo, Samcos, Full TSL de-cat, K+N panel, PE Phase II, I/C tilt.

Brun

Green lights are normal!
Worry when you get ambers

NM

MORE SO WHEN THE RED ONE FLICKERS !

markwild

OK - Just that I didn't get any off boost before.....

Cheers,

Mark

Dark Blue Mark

Is your KL set at max? If so I wouldn't worry to be honest. I get the odd random first green every now and then, but I wont worry unless it gets a bit worse.

MB

markwild

MB, it is at max sensitivity - I'll keep an eye on it, but the behaviour is different since the remap, but stable and consistent - I've done 1500 miles since then, so I've had time to analyse....

Mark

Dark Blue Mark

Im not sure how PE do their remaps, but I know John B runs slightly leaner settings on the TEK remaps he used to do. Bearing in mind the Kl is a lot more sensitive than the one the ECU uses, the KL may just be exaggerating a minor lean point. By lean, I mean safely lean. Give PE a call about it for peace of mind.

If it does get worse then maybe look at thinks like injector cleaner etc? I say this, as it appears to be when the fuel is dribbling in, rather than at WOT. Cant think of much else, maybe TPS worth a look too? Doubt it would be MAF or Lambda, as its the wrong symptoms for a failing one of those. Sure its ok though.

Of course, I might be talking crap

MB

john banks

It shouldn't be detting on cruise - and it is probably running standard mapping in that area anyway. Probably picking up a vibration.

A lot of engines don't show a flickering green until about 125 mph in top for a UK car.

A spike is what you don't want to see. At 4000 RPM for example the bottom green may flicker, you can often hear light detonation through the det cans if this happens. It is debated whether this level of knock does any harm though but it is usually easy to get rid of.

No amount of tuning will get rid of resonance or background noise which vary from engine to engine.

markwild

Cheers Mark and John.

It's possible that it is a vibration, because altering the load on the engine slightly could still remove the frequency - as can be seen when using low speed/high gear combinations and getting dash-rattle !

I'm less inclined to think its a spike, as it remains constant whilst that speed/throttle position is held, rather than suddenly appearing and then disappearing.

I'm working on a (well, if I ever finish my garden swing and new kitchen !) splitter for the I/C, so if it is a slight det, this may remove it, due to slightly lower charge temps.

John, interesting to note that the map won't have changed at this point of throttle, hadn't thought of that - I don't remember it doing it before, but maybe its a symptom of some other change - I lagged the D/P, fitted the K+N (rather than the ITG) and fitted an I/C tilt kit on the same weekend as the remap..

I'll keep an eye on it

Thanks again,

Mark

Dark Blue Mark

Im still working on my knock induced by gear mesh frequency theory

Know how many teeth are on each wheel?!

John, do they only alter the ECU map on boost? Guess there's not much need to adjust off boost? I get 1st green light flicker at 4k rpm on boost (STi4 decat) but not too worried about it. I dont drive at the top end, but the fuel pump looks like it doesnt cope too well up there!

MB

markwild

I get greens at full boost towards the top end - Chris at PE said that the pump was OK, as plenty of fuel was being delivered (At 100000 miles, I thought that this might be worth checking )

Always did get a bit of 'green' activity around the upper end anyhow.
Mark

john banks

Little value in changing off boost stuff if the VE of the engine isn't wildly different. Fuelling runs closed loop lambda so would undo changes you make there, ignition has been mapped with massive R&D by Subaru for economy, transients, emissions etc. It would be very difficult to measure torque in these zones with road mapping and of questionable value on most chassis dynos given unrealistic temperatures and airflows. Given that you could easily cross minimum timing advance for best torque if it isn't broke....

Dark Blue Mark

Sounds good to me

MB

skoosh

Hi Mark, my wagon underwent an injector purge at TSL on Tuesday and you wouldn't believe just how smooth she runs now, I would recommend this to anyone who's running at 100k miles like we are. Best 55 quid I've spent so far as the car's alot quieter also, could be worth a look mate.

Just my 2p worth.

Skoosh.

ps: R U coming on the Long Eaton run next sunday?

markwild

Skoosh - cheers - I was going to ask you how you'd gone on - might ask TSL to do 'the do' at the next service.

I probably won't make it on Sunday, - I'll PM you as to why...
Thanks anyhow,

John/Mark - makes sense not to map off boost - v. difficult for almost no gain - I noticed this morning that the same revs in 4th don't produce the sparklies, so this may add some weight to the 'vibration' type theory, or it may just be a slightly different throttle position.. - I'll let you know if the splitter or injector purge make a difference,

Thanks,

Mark