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High knock reading on PFC?

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Old 05-14-03, 12:01 PM
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bow leggin'

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High knock reading on PFC?

Can someone tell me what could be causing this? I will get a reading of 103 sometimes and even higher. I was told it could be engine noise, I could be running too rich and it could be the timing is off. Whe I was putting the belt back on the alternator pulley I turned the eccentric shaft pulley by accident, could that be the problem? I don't think it is but I could be wrong. Also I will be getting my car tuned next week sometime, im guessing that will eliminate the high knock readings by getting better air fuel ratios. I just wanted a second opinion on what this could be from. My guess is it's running too rich. Anyone else?

Thanks,
Dan
Old 05-14-03, 12:02 PM
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What were you getting before? Or what were you getting normally?
Old 05-14-03, 12:47 PM
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bow leggin'

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Im not really sure. I didn't have a knock sensor before. I believe normal is around 30-40 from what i've heard.

BTW nice avatar
Old 05-14-03, 12:53 PM
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Could be any of thoes reasons. Timeing, fuel ratio off. However I dont think turning the eccentric shaft pully would make that happen. But what the hell do I know.

Mine usually goes no higher then 60. However once after a hard run, I downshifted and let the engine drag it down a bit, I got a backfire, peaked at 114 knock, scared the living hell outta me. I figured later that it was just the resonation from the backfire that made it read so high.

I would sudgest posting this in the ECU forum under the PFC forum, if you havn't already. Most likey to get a good answer from someone that knows their stuff.

Edit: Link to PFC forum. https://www.rx7club.com/forum/forumd...?s=&forumid=47

Last edited by Mindphrame; 05-14-03 at 12:57 PM.
Old 05-14-03, 01:30 PM
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Originally posted by Scrub
Im not really sure. I didn't have a knock sensor before. I believe normal is around 30-40 from what i've heard.

BTW nice avatar
Thanks.

People have said that different cars get different readings.
If you normally get around 30-40 and then one day, you get 100, you might be in trouble.
Old 05-14-03, 01:43 PM
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knock readings on the PFC aren't accurate. I've seen 60+ just sitting at idle. Normal driving will go up to 100. Get a real knock sensor if you want to monitor it
Old 05-14-03, 01:44 PM
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alright thanks for the relieve. Who makes a good one?
Old 05-14-03, 04:55 PM
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probably your knock sensor is just loose. Get the tech manual and tighten it to spec. They are accurate enough BTW. Mine never reads more than 30, and goes to virtually 0 at WOT. Readings at idle are not as important as readings at WOT. If you want a better one, like say a J&S get ready to spend BIG BUCKS.
Old 05-14-03, 06:23 PM
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KNOCK SENSOR

Or buy engine knock alert from MSD.
http://www.jegs.com/cgi-bin/ncommerc...7&prmenbr=361;)
Old 05-14-03, 11:19 PM
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bow leggin'

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hmmm interesting...I'll have to tighten that ***** and see if that fixes it. I am fresh out of cash after my recent purchases.
Old 05-15-03, 12:22 AM
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Mine is as high as 200 or more alot. Even just idling sometimes the thing moves.

THE STOCK KNOCK SENSOR IS WORTHLESS.

actually, the sensor is ok, its just mounted in a poor location. Its just a freakin' microphone folks
Old 05-15-03, 08:48 AM
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BTW online manual here: http://www.iluvmyrx7.com
Old 05-15-03, 09:17 AM
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With the Power FC I've seen knock readings between 20 to 194?? Never seen 200 though...
Old 05-15-03, 09:40 AM
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The knock sensor picks up a lot of extraneous noises (those not necessarily associated with detonation). My readings went from about 100-180 when I was sequential, but after going non-seq it settled down to about 40 at WOT. No other changes were made other than some minor ignition timing adjustments.

If I recall the knock sensor readings would jump at the transition (spiking of boost).
Old 05-15-03, 12:03 PM
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bow leggin'

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I think once I get it tuned I won't be as worried Thanks for all the help everyone.
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