Knock Links. Caution.
 

I have come accross three K.L.s in the last three weeks which were not functioning.

On the WRX Wagon I had relocated the LEDs remotely and was impressed by how quiet it was with only two greens after a major power hike. Turbo, Injectors, Exhaust, Headers and Link ECU etc. When I removed the installation I found that some of the telephone cable wires used to extend the LEDs position had fractured.
All soldered back together for me by Andrew C. Obviosly telephone cable is too brittle. Use softer wire. Luckily the fault was detected before damage occurred.

The second occurrence was on a car where det was audible but only two greens were showing. I thought it would just be a case of turning up the sensitivity before sorting out the det issues. Shock, horror. On opening the original box, some of the legs to the LEDs were fractured. This box had probably never been opened before. A simple soldering job effected the repair.

A couple of weeks ago I was called to an STi 9, just off the motoway slip. No.1 piston had picked up in the bore and the repair was a complete engine transplant for £1500. The owner had been exploring the performance of his vehicle but had only seen two flickering greens.
By chance, after he got the car back, I asked him to check the garage had refitted his K.L. sensor and where was it located. I suggested he tap the block with a heavy screw driver and he had two greens. I then asked him to use a hammer but still only two greens. The K.L. was bought in a Group Buy about 18mths ago and transferred from the previous car to the 9. On openning the O/E K.L. box.....more fractured LED legs. Expensive.

So if you rely on a Knock Link check it regularly. I understand on some cars there is a full scale reading on turning the starter as the ring gear is engaged but unless you get a full scale reading, proceed with caution.

Similar thing happened to me, I now regularly test my kl with a spanner just to be sure.

9 times out of 10 when I start my car all the leds flash.

But when I received it brand new the red led was not soldered onto the board.

i had the same, no activity at all, i then opend the unit and moved the leds on extended cables for a more descrete fit and the LEDs were so loose i dont think they would have worked at all, the unit was brand new, i think this is a appouling, surely the units should be checked before selling them.......

Mine was faulty from new aswell the red led was not soldered well at all, still can't believe that the Link kl is the only one on the market.

Mine dived to red this morning when I missed the gear change in 1st.

Guess I know mines working!! Ouch......

I have had probs with both KL & LL :rolleyes:

I used CAT5 network cable to remote fit mine - I think I'll start checking it more regularly....

Fair warning, thanks for that.

Can save people expensive rebuilds.

FWIW, all the leds on my KL do light up when starting the engine.

Same Here
 

.....can't count the amount of times I have re-soldered mine. It was also faulty from new but luckily someone in the gp buy pointed that problem out.

I'm running 17psi plus AFR unit and recently the knocklink activity disapeared (grren flickering). Checked with the spanner - nowt. Fiddled with the wiring all the way back to the unit and took it for a run - no activity then a sudden red light flash (even though I used to get a gradual build up of lights and when testing with the spanner all the lights flash)

It just shows that the instruments themselves do occasionally need checking.

Thanks Harvey

There is a Japanese company who sells something similar but they cost 2-3 times as much. The unit does look a lot better made though. I'll try and dig out a link.

Harvey.. no offence but im not suprised if you use phone cable!!

Phone cable is a solid core cable, really you need to be using something such as ribbon cable.. I appreciate this makes it harder for those that cant solder as well.. but It makes a difference..

Or you could steal a patch cable from a pc and use that, as they use stranded cable. to make it flexible.. Most cat5 / cat6 cable used for flood wiring is solid core as well so no good.

A couple of tips..

Remove the LED's paying carefull attention to which is the cathode and anode, as if you get them the wrong way around then they will not illuminate.. or look to see which lead goes to the 'big bit' in the led.

Remove them all, do not use too much heat as led's dont like too much heat.. or simply snip the legs leaving a little extra to grab on..

Desolder the legs or whats left of what you cut off.. heat the solder and bang the board quickly and firmly on a desk to knock the solder out if you dont have braid or a solder sucker..

Solder in some pcb pins instead of the legs..

Tin the ribon cable wires and extend the led legs.. heat shrink over the connections..

repeat..

You can common up all one side of the Leds as I have done, but I wont try to explain it.. ill just keep it simple..

HTH

David

how do you get an sti enginefor £1500? - or did the customer have a spare and that is just the transfer charge??!

Nice one, will double check mine on the weekend.

simb

My KL and LL stopped working too. KL worked fine (well into amber) when tapped block with a spanner but only registerd 2 greens when driven at most sensitive setting :confused: . My LL just chucked it altogether :(

To be honest i have come across the same thing several times while fitting KLs here at Jap.

You come to test them and one or more LEDs doesn't work sometimes.

It's for this reason that I now test every single knocklink we sell, personally.

I used to own my own electronics company making PCBs, so I'm a stickler for decent soldering and TBH some of the boards I've seen would have earned my old employees the sack!

When fitting a Knocklink yourself ALAWAYS check that ALL LEDs can light.

Thanks

Rich

just checked mine and it looks like two of my leds aint working, both the red and the 2nd yellow led are 'wobbly loose' and dont have a decent connection. Thankfully mine never reached as far as the first yellow led!

so thanks for sharing this, im off now to make sure all of them are soldered properly!!!!

Yeah, thanks for the heads-up everyone. Hopefully should get mine soon thro the GB, then going to remote mount LEDs, so good opp to inspect the solder joints (ex Electronic Apprentice, also a stickler for good solder joints!)

Question (prob to David Wallis or Rich Wild)...having not yet seen a KL in the flesh, are these LEDs common anode or common cathode?...just trying to save 4 wires going to the remote housing.

Cheers

S

Has anyone got a circuit diagram for a Knock link? if the soldering in the units are a little dubious, I'll want to make my own as I'm competant with electronics and soldering instead of risking my engine on some one elses mistakes/faulty components

Rather dissapointing that something that is just a chip and few LED's and a bit of plastic, which, component-wise costs a few quid to make, yet be charged £150 and be prone to failures like this :mad:

It's not on really

Oh great
Just getting one of these to stop me worrying about my engine.

It seems I will be worrying now if the blasted thing is doing its job.

I don't have one fitted to worry about!!

Dry joints are common all over the PCB, not just the LED's. Just adjusting the sensitivty will likely cause a dry joint on the variable resistor....... (I agree with Rich :)).

Richard

I've noticed yesterday that both my oranges are out. :( Not good, as I saw the red.

I don't let it run to two green, but the poor quality fuel from Leeds. ;)

I will investigate later today to see why and I'll post up here why they're not working.

Spenny B - Common on Cathode mate ....

I had no idea it was going to be such a wide spread problem as is now evident and I concur fully with the remarks about the quality of the soldering. It should not happen on a new product which is critical to the well being of our engines.
Although active around Subarus for some time, I had to find out for myself only a few weeks ago, so I am surprised the problem is not common knowledge. Make sure your contacts are also aware not to rely on the K/L implicitly.

Only on some cars does the starter pawl activate the K.L. fully.

D.W. Fully take your point about phone cable but it was to hand when the job was done.!!!

Thanks to Andrew Carr for remaking my K.L. properly and also sorting my Serial Link which suffered from dry joints and I butchered with a soldering iron.

£1500 for an STi 9 engine swap including fitting and it was a swap.

Interesting point made by dowser, had the dry joint problem on mine when setting the sensitivity up ( it was new then ). Thought it was a one off!!

Hmmm....

I've only just installed a knocklink, followed the instructions regarding adjusting the sensitivity etc... but I dont get *ANY* activity at all!

The first green LED seems to be dimly lit... and flashes Bright when the engine is cranked..
I tried tapping the block next to the sensor and didn't get any reaction.

Does anyone have a follproof way of testing these bu@@ers?
I'm not sure where (if) the fault is?
Any idea what voltage the knock sensor sends out?

Ideas greatly appreciated!

My two oranges have broken away from the circuit board.

I'm now going to use the LEDs remotely, and incorporate them into something else. Hopefully, this will eliminate the problem of them breaking.

I'll get some pictures too :D

This really is crap, obviously don't know the percentage failure rate to the number of units sold, but either way, it's too high....tempted to design and make my own unit, then market that!

Has anyone had any conversations with Link about this?...be interested to hear their excuse(s).