Knock sensor... Is it worth it?

[Nikkormat]

Right now I'm running without a knock sensor, I could add one fairly easily but it would be an added $30.

Is it worth adding one? Will it even work properly on a noisy old AMC?

[Stuka]

Well technically you would need 8 sensors, unless you plan on only detecting it on a single cylinder. And knock sensors work fine provided they are placed in the correct spot. Even if you have some noisy valve train. As for being worth it, it depends how much you like to protect your engine from destroying a piston.

[WT91]

I don't think the GM TBI system can even support 8 knock sensors.

It's up to you really, just ask yourself how many aftermarket TBI kits come with a knock/esc function? It's not overly necessary IMO.

[AwesomeJ10]

I don't run a knock sensor. The knock sensor is literally a 'microphone' that can detect pinging (from too much advance) and will back down the timing. It requires the use of the ESC (which I think we unplugged from your junk).

AMC V8's love (and I mean LOVE) advance timing, so unless you twist that dizzy so far advance that it won't start (or crank up your timing table) it will never ping and therefore, there is no reason to run the knock sensor.

too many unnecessary wires. Remove 'em all. Gone. done.

[FSJ Guy]

When I talked to AFI about knock sensors, they said they do not recommend them.

As WT91 said, not many aftermarket systems run them. I never bothered to hook one up, either. You can tie the sensor to the 5V line to prevent noise, disable knock retard in the bin or zero out the retard table in the bin.

[shimniok]

I don't run one. I disabled knock retard. I've read on several posts here and there about knock sensors for GM motors giving false positives on AMC motors. I just try not to go crazy with the advance curve. I worked my way up slowly to where it's at now.

[Bill usn-1]

The KS has no real benefit.
It was there from the factory for emissions.
If the engine misfired it sends unburned fuel out the exhaust.
They needed to prevent it with the higher engine temps and leaner mixtures.
So they ran the KS.

Carbs did run a KS and EFI doesn't need it either.
Lots of misconceptions on the web.
Like the oil pressure switch was a safety device.....not true.

[rocklaurence]

My understanding is that you have to hook it to a smart processor that compares the Ping/knock to a set profile [you shouldn't get false triggers because nothing else make that type of noise to fit the profile]. I believe the smarter ignition modules allow this and it's definitely required under boost.

[Bill usn-1]

HMM so no one ever had a boosted engine before knock sensors were used?
You are correct that the sensor circuit is tuned to the cylinder volume of each application due to it's specific ping frequency.
Any engine mods like harder motor mounts or headers or roller rockers or mechanical lifters can cause false pings to be detected by the sensor.
So you end up losing power instead of improving performance with EFI.

Proper fuel ratio and timing under all engine loads is all that is "needed".
A proper functioning KS is nice to have but not required to have.

[rocklaurence]

I know that MSD and the others offer those options. The KS is only a sensor that provides an input to the processor. If the ECM your using has that function it should be easy to install.

[JeepsAndGuns]

I installed one on my 401, however lots of tuning and testing, all I found is it does not work with a AMC engine. I disabled knock retard before tuning (didn't want it retarding the timing while tuning). I could set there at idle and watch the knock counts go up. On any given data log I would thousands and thousands of knock counts. I left knock retard disabled and never plan on turning it back on.