Can I unplug the knock sensor?

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Aug 8, 2003 | 04:48 PM

Budman68

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From: DFW TX

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St. Jude Donor '07

Can I unplug the knock sensor?

Will this help the car not kick the timing back? I'm running a MAP type system.

Aug 8, 2003 | 07:17 PM

tempest

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From: walled lake MI

Re: Can I unplug the knock sensor? (Budman78)

if you are running the stock ECM (and even any aftermarket that does use the knock sensor), then i suggest against it. in addition to adding some default spark retard to prevent knock, there is a chance you will do some serious damage if there really is knock and the ECM cannot react to it.

ski_dwn_it put up some great post responses on the subject if you'd like to search.

[Modified by tempest, 7:20 PM 8/8/2003]

Aug 8, 2003 | 07:42 PM

vader86

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Re: Can I unplug the knock sensor? (Budman78)

Do you know why the ECM is kicking back your timing?

You better fix it or find out. The knock sensor can fail, so you may have a bad one. But dont unplug it with the car running.

Aug 8, 2003 | 07:48 PM

cdnguyred88

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From: Calgary, Alberta

Re: Can I unplug the knock sensor? (vader86)

unplugging it could ruin a perfectly good motor. :iagree:

Aug 8, 2003 | 07:59 PM

jackdaroofer

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Re: Can I unplug the knock sensor? (Budman78)

:cheers: If you think there is a problem, there are tester circuits available to determine actual sendings

I found that the plastic housing on mine ha cracked and corrosion set in and I wasn't getting propoer voltage

Not sure if this helps

:seeya

:steering:

Aug 9, 2003 | 03:38 PM

GRX

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From: Silicon Valley Kalifornia

Re: Can I unplug the knock sensor? (Budman78)

Here is nifty idea that forum member JoBy came up with. Maybe it can help you find the problem. Sometimes exhaust rattles or some sheetmetal noise can feed the sensor bad data. Be all means, do not disconnect it. The sensor threads need sealant in order for the sensor to function correctly. Also, the GM manual states that after being installed, a used sensor should never be re-used!!! Good luck. :chevy

Aug 9, 2003 | 03:48 PM

fiberglasscoffin

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From: sussex nj

Re: Can I unplug the knock sensor? (Budman78)

in my 94 with the knock sensors unpluged it pulled timing back from start to wot

i think a safety feature

Aug 10, 2003 | 06:20 PM

CFI-EFI

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From: The Top of Utah

Re: Can I unplug the knock sensor? (Budman78)

Here are MY views on the subject. A scanner determined that I was getting knock counts. I filled the tank with the best gasoline available, timed the engine to 0, and STILL got counts, while revving it in neutral (no load). That told me that the sensor was picking up some external "noise". Exhaust? Motor mounts" Piston slap? Who knows. I was certain I wasn't getting knock or detonation under those conditions. I disconnected my sensor. I believe in the virtues of a properly functioning knock sensor, but I couldn't abide by the ECM pulling timing out, needlessly. I now set my timing by 1/4 mile, mph numbers and audibly listen for the sound of pinging, like in the good old days. Can disconnecting the sensor damage the engine? YES! If you're not paying attention to "business". Good luck, and...

RACE ON!!!

[Modified by CFI-EFI, 4:26 PM 8/10/2003]