Custom knock sensor idiot light?

[Caveman Tony]

Theoretically, anything is possible.

Was thinking I could install an OEM or replacement knock sensor wired to an indicator light, so that the light would indicate if the sensor picked up any pings.

Any suggestions?

[TC]

I have one of these.....

http://www.msdignition.com/Products/Tools/Ignition_Tools/8964_-_Engine_Knock_Alert.aspx

[Barry Donovan]

yes, anything is a possible.
find how sensor works, choose your light bulb..
a flickering one can come from a computer, use resistors to drop to 5 or 3.3v

I just did that recently..light senses like a hard drive light on a pc.
I could guess that is exactly how those look if to monitor across a light bulb..like a hard drive on a pc busy sometimes, and not busy, and all busy.

[dieselgeek]

Theoretically, anything is possible.

Was thinking I could install an OEM or replacement knock sensor wired to an indicator light, so that the light would indicate if the sensor picked up any pings.

Any suggestions?

Hope that Matt Cramer sees this post and repsonds.

I have used a few different aftermarket knock sensor systems with mixed results. Any particular engine "knocks" at a different frequency, so it's hard to use a knock sensor from one application on another that's not identical. Things like headers and valvetrain upgrades can throw off the system's ability to pick up knock.

What's the application?

[Caveman Tony]

Application A: Mercruiser 350 in a heavy-ish 23' Wellcraft
Application B: BBC in a 4x4 truck, SM465 4-spd
Application C: SBC in a slightly lighter, older, lower, greener truck, with a 200-4R and 4.10s, and possibly NOS

[Caveman Tony]

I have one of these.....



http://www.msdignition.com/Products/...ock_Alert.aspx

And how do you like it? Any Pro's/Con's?

Or is it sitting on jackstands?








J/K, TC... that one was too easy. Couldn't resist.

[dieselgeek]

Eh, you can try one but you'll have to knock on the motor to know if they're working or not.

In this day and age, few engines make their peak power at "max timing before knock" (that's an old wivestale that TC might believe, but isn't true, lol).

Why not just run them at mean best timing on proper fuel and not worry about knock?


Either way, the highest end aftermarket systems start with the J&S Safeguard (google 'em). I've used a Knocksense with good luck (the MS version, but they have a standalone one with an LED like you seek), so long as it was using the OEM sensors for an engine they were originally intended - in my case it was a stock 350 similar to your marine engine, and I also used one in a turbo GMC Syclone using the OEM sensor, with a Knocksense module feeding into the MS.

In all cases, I never was sure the engine was actually "knocking" when the LED was going off. Personally I discourage the use of them because if you're knocking the engine, you're screwing it up, period, and that's never good!

[Loren]

Just if you're dozin' a little and the engine is getting hot. It does seem like you ought to be able to have the appropriate sensor for the motor, when there is one, and have it trigger a light.

[anotheridiot]

the frequencies a knock sensor picks up are barely noticable. the circuit it makes is used to adjust timing and fuel so I would think any resistance (bulb) would delay the signal to make the adjustment. I'm guessing you find the absolute minimum triggering relay to lite that bulb.

[Caveman Tony]

the frequencies a knock sensor picks up are barely noticable. the circuit it makes is used to adjust timing and fuel so I would think any resistance (bulb) would delay the signal to make the adjustment. I'm guessing you find the absolute minimum triggering relay to lite that bulb.

It wouldn't be for any 'automatic' timing adjustment... just a warning to tell me to back off, or that I'm being an idiot with the timing light, or for other relatives who are very hard of hearing.

[anotheridiot]

It wouldn't be for any 'automatic' timing adjustment... just a warning to tell me to back off, or that I'm being an idiot with the timing light, or for other relatives who are very hard of hearing.

Ok, my mistake, I thought you were dealing with computer cars where the purpose of the sensor is to adjust lead or fuel for noises nobody can hear and were trying to indicate when the computer was doing that.

[Matt Cramer]

Hope that Matt Cramer sees this post and repsonds.

There's a couple different ways a device could do this. The MS1/Extra knock circuit could be used as a very crude standalone knock light if you added a 5 volt power supply:

http://www.msextra.com/doc/ms1extra/MS_Extra_Hardware_Manual.htm#knock

It simply detects where the voltage from the knock sensor exceeds a certain level and turns on the light for 0.4 second interval.

The KnockSense that Scott mentions is a similar idea with better filtering (and a lot more convenient if you don't want to build your own circuit). The downside of this approach is that it uses one knock level across the board instead of different levels at different RPM.

It's possible to get a bit more sophisticated. The MSPNP Gen 2 knock circuit uses an analog circuit that changes the threshold level based on RPM. More sophisticated setups can also only listen during a set crank angle window, use a more flexible way to have the threshold level change programatically with RPM, even set different knock levels for different cylinders, but at that point, you're way beyond a simple warning light.

[TC]

The MSD one has an adjustment for sensitivity that you set by revving the motor to 2500rpm........ They've had this same knock sensor for the last 20 years, I'm figuring it probably works better than some home built unit that has no real R&D behind it.......

[dieselgeek]

The MSD one has an adjustment for sensitivity that you set by revving the motor to 2500rpm........ They've had this same knock sensor for the last 20 years, I'm figuring it probably works better than some home built unit that has no real R&D behind it.......

Who cares what you're figuring? you don't even have a running car to test it on. You're the PERFECT msd customer, you buy something because you read about it in a magazine, then you never install it so (a) you have no idea how or if it works and (b) MSD loves you because you'll never bug them with a tech support call.

Alex, this post was for people EXPERIENCED in using knock sensors. Any idiot can read a magazine and tell us what the marketing department wants us to see. If you've USED and tuned with this sensor, keep posting. If not, please buzz off.

[TC]

Who cares what you're figuring? you don't even have a running car to test it on. You're the PERFECT msd customer, you buy something because you read about it in a magazine, then you never install it so (a) you have no idea how or if it works and (b) MSD loves you because you'll never bug them with a tech support call.

Alex, this post was for people EXPERIENCED in using knock sensors. Any idiot can read a magazine and tell us what the marketing department wants us to see. If you've USED and tuned with this sensor, keep posting. If not, please buzz off.

I ran it on my camaro before I parked it dumbass, so yes despite your delusions of what I've done, I have experience using one....... MSD spends Millions of dollars a year in R&D along with decades of experience of being in the business..... It's funny how you guys try to reinvent the wheel, when MSD has already done a good job at doing it. And what does it matter to you, you flat out said the Knock Sensor on the MegaSquirt was useless and you never were able to get it work......... All your doing is just arguing to argue, I say the sky is blue..... What do you say........