Knock sensing on cars not equipped with knock sensors [Archive]

Dzaster

07-04-2009, 04:32 PM

What are the option for detecting knock if my car doesn't have a knock sensor from factory. Anyone?

I check Knock Link, but from the short read on there site it seems to work off your cars existing knock sensor. My car has no knock sensor.

I see there is also knocklite, but that also seems to work off existing knock sensor.

Any other after market kits out there?

Update: Okay, it appears they knock link has a kit with knock sensor and harness. Now does anyone know where they can be purchased from US?

CG10DET

07-04-2009, 05:51 PM

The sensors are generally built into the engine, however there are a few aftermarket kits, however you can generally hear it before the device will detect it.

Dzaster

07-04-2009, 09:15 PM

I understand that my motor doesn't have a knock sensor, but just trying to find a decent kit that will get me some knock monitoring. Seems the knock link has fairly decent feedback.

I have already taken steps to try this DIY.
http://autospeed.com/cms/article.html?&A=0353

http://us1.webpublications.com.au/static/images/articles/i3/0353_8mg.jpg

I'd still like to see if there is an aftermarket kit readily available for my car and is within my budget.

bluesnowgt

07-05-2009, 12:17 AM

i havnt heard of a motor that doesnt have a knock sensor... u would need one if ur car is fuel injected and ran by a computer. if its carb'd then i would say it didnt need one...but since ur car is fuel injected, the computer reads off the sensor and retards timing wen knock is sensed....

Dzaster

07-05-2009, 03:22 AM

Hmmmm............I checked my Tercel forum and a very credible source stated that my motor don't have a knock sensor. IDK. You have a point though about retarding timing.

Accord2nrz

07-05-2009, 06:42 AM

The best way to find out for sure is to take a look at an ECU pinout diagram for you car. or Download a SHOP manual for your car which lays out the ecu connections.

If your car has a knock sensor the ecu slot for its connection will be listed.

If you dont have one you can install one, the toughest part of the install is drilling into/tapping the block and screwing it in that way. When you do this you need to keep it away from areas that make noise (sounds wierd) but generally dead center to the 4 cylinders to get the best reading.

I'm glambling that your car has some sort of knocking mechanism. Or since it's OBD 1 simply retards timing based on AFR in relation to cam position or something of that nature. Simply put if there isn't a knock sensing mechanism then your car was likely to be seriously detuned from the factory to give a huge margin of safety in the unlikely event that detonation occurs.

Detonation events occur all the time in ALL motors on a daily basis, regardless of whether or not its factory or highly modified, in many cases though its within tolerance of what the factory deems acceptable, this is why I'm assuming you car has one somewhere in there.

messiahx

07-05-2009, 07:31 AM

I've heard of/seen pictures of "det cans". Basically a styrofoam cup with a long 1" diameter tube run into some big ass headphones. The styrofoam cup is then placed against the engine block or an engine mount. Apparently you can hear very well when knock occurs. A couple of the more experienced members on miataturbo swear by this contraption.

Accord2nrz

07-05-2009, 05:03 PM

I've also heard of home made contraptions where a mic is basically put to the block wired up to an amplifier in the car, very crude but seems to work.

RPW00Mirage

07-06-2009, 04:19 PM

CG10DET

07-06-2009, 05:01 PM

how do these diy jobs work?

Mrdb

07-06-2009, 11:16 PM

If you have laptop.

Simply buy cheap pc mic. extend wires and fix to clamp and clamp to block.

Plug into laptop and then plug headphones in. You can record using sound recorder also.

You will hear knock well before any knock sensor....

RPW00Mirage

07-07-2009, 12:18 AM

the engine sounds like a heavy metal band, on this setup engine knock sounds like a thud in the mix.

zamiex

07-09-2009, 10:35 PM

hmm.. im just curious to differentiate the knock sound with other sound...
i mean like knock sound vs lifter sound or other mechanical parts...

whats the best way to hear knock, while the car moving or just stand still

Dzaster

07-09-2009, 11:06 PM

I think you should never really here any detonation while still, unless on a dyno and engine under load. If you can dtect knock while motor not under load then you have some ignition issues.

maxgtr2000

07-10-2009, 05:42 AM

Here (http://www.mx5nutz.com/forum/index.php?showtopic=30983&st=20)is a thread on the mx5 site for det cans and someone built a bandpass filter to be able to hear the knock a little better, so seemingly it amplifies the noises of the knock frequency range.

Turbineguy

07-13-2009, 02:32 AM

I don't know what all of you are driving but a styrofoam cup on an engine mount or some Radio Shack contraption is not what I would trust my engine to. Knock is one of the most destructive and common engine issues you can run into and I wouldn't entrust any car I own to a foam cup or some sound amplification device that old people use to hear the tv.

http://www.rallysportdirect.com/shop/turboxs-knocklite-p-2178.html

I would also like to know how someone who doesn't know what they're hearing or listening for is going to filter out drivetrain noise, valvetrain noise, accessory noise, oil pump noise, etc and pick out a knock event. Long term mild inaudible knock can be just as destructive as a major single knock event due to fatigue issues with pistons being made of aluminum. Don't cheap out on knock detection.

Dzaster

07-13-2009, 06:16 AM

Understood. I've come across that knocklite while looking around. I noticed that it can be used for programmable shift light function. That I like!

However, my car don't have a knock sensor. Nor is there a pinout for it on my ECU.

I just ordered a knock gauge(LED type) as well as stock knock sensor that my block has provisions for.

I intend to use both, audible and sensor type, together. Heck, I hope I never hear knock. I don't care to push it that far. I just want to know that things are good in its current state and if I get crazy I'll fine tune timing a little from its current conservative state.;)

Turbineguy

07-14-2009, 02:15 AM

You don't need to have a knock sensor already installed or provisions for one in the ECU. The TXS Knocklite is a stand alone that can be fed a signal from an OEM sensor or you add in a Bosch sensor with the light and either piggyback it on the stock sensor or use it (in your case D) by itself.

Dzaster

07-14-2009, 05:01 AM

I think I'll go with one them then. What's cool is that it takes into consideration RPM, so when up on RPM the knocklite would seem to decrease sensitivity so that it's not alerting of normal engine feedback/noise. And again, I like the shiftlight incorporation. You know if the shift light is distinguishable from knock in anyway--color, illumination time, etc.?

Update: To answer my own question, YES, the shift light emitted is green where as the knock detection is emitted Red. Also pretty awesome about it is that you program the unit to learn the what are the normal noises fo the motor at given RPM ranges. Pretty spiffy. I must have one, and will have one. Thanks Turbine!

Dzaster

07-29-2009, 05:12 AM

And I have a knock gauge for sale HERE (http://www.diytuning.com/forums/classifieds.php?do=showad&adid=7&title=knock-gauge)

Accord2nrz

07-29-2009, 05:28 PM

That link doesn't work. Just lettin ya know :)

Dzaster

07-29-2009, 08:02 PM

Link fixed. Thanks.

Dzaster

08-01-2009, 07:05 AM

I got the TurboXS Knoclite today. Gonna put it in tommorrow. Will have some feedback and perhaps some pics or vids soon. Thanks Turbineguy again for the heads up on such a unit.

CG10DET

08-01-2009, 10:17 AM

I've been looking at these also, so I'm interested to see what you have to say about it!

Remember not to trust it 100% it's an indicator and can give a false reading.

Dzaster

08-01-2009, 10:40 AM

Yeah, I'm gonna go with the DIY/Ghetto audio kncok detector as well. Just to see if I do get knock if I can distinguish--and also to assist and confirm.

Dzaster

08-04-2009, 06:04 AM

So it has been installed as of today. And set. Just has not been tested to see how well it works.
Contents;
http://i525.photobucket.com/albums/cc340/dzaster96799/WIP%20Thread/IMG_1354.jpg

Installed:
http://i525.photobucket.com/albums/cc340/dzaster96799/WIP%20Thread/IMG_1367.jpg

It wasn't set and I was driving around and all the lights were on in this thing.

I began the process ofsetting it up by programing the shift light, shift point first. Then I moved on to setting the 3 levels/RPM sensitivity ranges. First you set at idle, then you set at half of near redline, then last is near redline. All done while stationary, car in neutral.

After setting it I didn't go out as it was time to eat so called it a night. Will report later and have some vids for you guys as well. Hopefully just to see the shiftlight and no knock. I guess I could simulate some knock. We'll see.

Dzaster

09-07-2009, 02:08 AM

Back with a my little creation of a knock listening device as well as some thought on sorting out some stuff with the TurboXS Knocklite going off at like 2700rpm--reporting supposed light knock.

First off, the knock listening device.
http://i525.photobucket.com/albums/cc340/dzaster96799/Projects/Electronic%20Det%20Can/IMG_0018.jpg

Seems to work just fine as I tested it real quick by clamping the mic to a exhaust manifold bolt/nut and had teh car idling. Could hear some clicking and what not. But as T-Guy stated, determinining what is knock/det over engine noise will be the challenge.

As for the TXS Knocklite, I did some light research on it on different forums and it seems that folks have had to play with teh sensitivity levels. Also, something I totally over looked. Since my motor doesn't come with a knock sensor I had to rig my own and ran the wire seperate of the harness. Well, I recently came to the realization that knock sensor wires are generally shielded within a harness so perhaps, its getting some excessive feedback.

I also bought a bottle of Lucas Octane Booster to see if it changes the characteristics of the knocklite's readings. Of course one thing at a time so can narrow it down to the actual problem--if there is a problem.:rolleyes:

Turbineguy

09-07-2009, 03:22 AM

Dzaster

09-07-2009, 03:39 AM

Haha! Oh crap! I think the wire is tie strapped with the portion of the harness loomed for the alternator--however it is outside. It also runs throught the firewall with some other stuff hoses and wires.

I was gonna rewire it shielded anyways but will be sure its away from alt or igntion. Just gonna find me some appropriate cable.

Dzaster

09-19-2009, 02:21 AM

So I've finished my little listening device completely and upgraded to some all-out headphones and added an extended battery pack.;)

http://i525.photobucket.com/albums/cc340/dzaster96799/Projects/Electronic%20Det%20Can/IMG_1453.jpg

I've actually used it over the past few days clamping it to the back of the block near the knock sensor. Seems to work nice to. The Knocklite has been going off when not in boost and when I really didn't think knock was present. So I listened with the knock listening thing and heard nothing, but same sound just a rise in RPM. Anybody care to share there thoughts sound clips on how it sounds?

Another thing, I thought that I had a slipping clutch because I was getting faint jerky acceleration--both in the seat of my pants and on the datalog. I thought it may have been the Knocklite because it taps into the ignition for an RPM signal. I disconnected it and no more jerky.:confused:

I think I need to find another source for RPM signal other than the ECU.

Also, using shielded wire for the knock sensor did nothing. Well, it still alerted of knock when none was present. Turning down the sensitivity actually did work. But I will set things up again once I find a different RPM signal for the Knocklite and confirm that it doesn't cause any jerky accel.

Dzaster

09-19-2009, 02:23 AM

Are the wires for the Knocklite run anywhere near plug wires, coils, or any crank triggers? If so look at a reroute or sheilding due to electrical noise from the ignition system. Also keep the wires away from the alternator.

Also, my knock sensor stock mounting location is just above the alternator, but nothing gets more than a few inches from it.