Spark knock ..... how much is "normal"
Le Mans Master
Joined: Sep 2001
Posts: 7,928
Likes: 1
From: More cowbell...
St. Jude Donor '04
Re: Spark knock ..... how much is "normal" (VetNutJim)
The thing to look at is not knock count, but knock retard. If you are not retarding your spark advance, then there isnt enough knock for your ECU to think it is a danger. Many times I see 100-300 knock counts through first and second gear, and there is very little (if any) spark retard. When I am hitting 3rd gear, however, my knock count sometimes jumps, to like 3000, or something along those lines, and I start getting a degree or two of spark retard. The reason the count isnt important- the longer you have your engine running, the higher the total count gets. What you dont want is a huge ammount of knock, at one time. (at least that is how it seems to work on my '92).
Racer
Joined: Sep 2002
Posts: 317
Likes: 1
From: Maple Valley WA
Re: Spark knock ..... how much is "normal" (VetNutJim)
Just starting the car, I get a thousand or so counts. While running, I'll see jumps anywhere from 300 to 800 counts as I'm hitting the accelerator at times with retards up to 10 or 11 degrees to go along with it.
Is this normal? Dunno, I bought the car used and I'm still running down driveability issues. She's got 118k on her...
Jay
Is this normal? Dunno, I bought the car used and I'm still running down driveability issues. She's got 118k on her...
Jay
Drifting
Joined: Mar 1999
Posts: 1,931
Likes: 1
From: Norcross GA
Re: Spark knock ..... how much is "normal" (JayH)
Normal,.. I'd suggest not many engines will do that. Is something wrong here,.. that is subjective Q. What is banging around in your engine? Has someone improperly tuned the combo?
Can it be tuned out,.. it is a safe bet that it can. Is it a stock engine? PROM?
Can it be tuned out,.. it is a safe bet that it can. Is it a stock engine? PROM?
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Re: Spark knock ..... how much is "normal" (ZylaRace)
If your getting 3000 counts on startups, you have issues. Like a lifter that is bleeding down then pumping up after oil is supplied. :skep:
It is normal for the ecm to envoke the knock sensor on startup, it does it on several calibrations to make sure the sensor itself is alive and well. Sorta of a systems check. But it should only be a count or two, not 3000. That is crazy.
Here is a WOT run with Rocket Fuel (94octane gas + Toluene) in my car. Notice their is none and the amount of timing I am running to boot on a ~12:1 comression engine.
You might want to start poking around to see what is causing it. It most likely is NOT real detonation, but rather something rattling, not getting oil right away or something.
:cheers:
[Modified by ski_dwn_it, 11:42 AM 4/24/2003]
It is normal for the ecm to envoke the knock sensor on startup, it does it on several calibrations to make sure the sensor itself is alive and well. Sorta of a systems check. But it should only be a count or two, not 3000. That is crazy.
Here is a WOT run with Rocket Fuel (94octane gas + Toluene) in my car. Notice their is none and the amount of timing I am running to boot on a ~12:1 comression engine.
You might want to start poking around to see what is causing it. It most likely is NOT real detonation, but rather something rattling, not getting oil right away or something.
:cheers:
[Modified by ski_dwn_it, 11:42 AM 4/24/2003]
Racer
Joined: Sep 2002
Posts: 317
Likes: 1
From: Maple Valley WA
Re: Spark knock ..... how much is "normal" (ZylaRace)
Normal,.. I'd suggest not many engines will do that. Is something wrong here,.. that is subjective Q. What is banging around in your engine? Has someone improperly tuned the combo?
Can it be tuned out,.. it is a safe bet that it can. Is it a stock engine? PROM?
Can it be tuned out,.. it is a safe bet that it can. Is it a stock engine? PROM?
Jay
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Thread Starter
Drifting
Joined: Oct 2001
Posts: 1,439
Likes: 4
From: Kewaskum Wisconsin
Re: Spark knock ..... how much is "normal" (Hole-Shot)
How much (if any) spark knock counts could be considered "normal" under WOT? Or should I not have any knock counts?
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Re: Spark knock ..... how much is "normal" (Hole-Shot)
Hole-shot,
None is ideal, that is why I provided my log, you see there are none at all. if you are getting any spark retard, or counts, then the ecm is pulling way more timing than it needed. If it only pulled the optimum timing out at each knock incident, then our job of tuning would be done. Unfortunately that is not the case, it goes overboard and takes too much out, hence hurting performance.
I wish there was a better answer, but really the only one is ZERO.
:cheers:
[Modified by ski_dwn_it, 2:49 PM 4/25/2003]
None is ideal, that is why I provided my log, you see there are none at all. if you are getting any spark retard, or counts, then the ecm is pulling way more timing than it needed. If it only pulled the optimum timing out at each knock incident, then our job of tuning would be done. Unfortunately that is not the case, it goes overboard and takes too much out, hence hurting performance.
I wish there was a better answer, but really the only one is ZERO.
:cheers:
[Modified by ski_dwn_it, 2:49 PM 4/25/2003]
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Re: Spark knock ..... how much is "normal" (Mini_K)
at WOT i get like 20 to 30 and i thought that was alot but compared to some of yalls i feel special now :yesnod:
Le Mans Master
Joined: Sep 2001
Posts: 7,928
Likes: 1
From: More cowbell...
St. Jude Donor '04
Re: Spark knock ..... how much is "normal" (ski_dwn_it)
ski-
Isnt that only killing power if it is retarding the timing?? Some times at WOT, I get some knock, (usually in the 20-30 counts range), but I am not having my timing retarded at all. Not sure how else it could affect performance.
Isnt that only killing power if it is retarding the timing?? Some times at WOT, I get some knock, (usually in the 20-30 counts range), but I am not having my timing retarded at all. Not sure how else it could affect performance.
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Re: Spark knock ..... how much is "normal" (MarkLT1)
ski-
Isnt that only killing power if it is retarding the timing?? Some times at WOT, I get some knock, (usually in the 20-30 counts range), but I am not having my timing retarded at all. Not sure how else it could affect performance.
Isnt that only killing power if it is retarding the timing?? Some times at WOT, I get some knock, (usually in the 20-30 counts range), but I am not having my timing retarded at all. Not sure how else it could affect performance.
I know what you are saying, but if the knock sensor is triggered its pulling timing, I have never seen it count, but not pull timing. My calibration is surely different than yours, and I'm no expert on each bin out there, so maybe some have a program that says they have to have X consecutive counts before the timing is retarded. Who knows? But in every case I have ever seen, the knock sensor takes action by pulling out some sort of timing. Do you have logs of this ?
Team Owner
Joined: Apr 2001
Posts: 22,267
Likes: 3
From: Dallas TX
Re: Spark knock ..... how much is "normal" (JayH)
Just starting the car, I get a thousand or so counts. While running, I'll see jumps anywhere from 300 to 800 counts as I'm hitting the accelerator at times with retards up to 10 or 11 degrees to go along with it.
Is this normal? Dunno, I bought the car used and I'm still running down driveability issues. She's got 118k on her...
Jay
Is this normal? Dunno, I bought the car used and I'm still running down driveability issues. She's got 118k on her...
Jay
Team Owner
Joined: Apr 2001
Posts: 22,267
Likes: 3
From: Dallas TX
Re: Spark knock ..... how much is "normal" (froggy47)
Excuse the newbie question, how can you tell what your knock count/retard is?
Told ya, new to this forum.
Thanks!
Told ya, new to this forum.
Thanks!
