Knock counts when starting...
Le Mans Master
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From: Sachse Texas
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Re: Knock counts when starting... (Glock'94)
2,000 counts?!? I have not checked mine is a long while since I have disabled the knock sensors, but I don't think I ever got anywhere near that many counts. I would have to look at it again.
Former Vendor
Joined: Jun 2001
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From: St Marys PA
Re: Knock counts when starting... (Vette92)
I get like one or two, maybe! I think that your scanner software does something funny if I recall correctly. I think also that our cars advance knock at startup until knock occures to make sure the sensors are working then backs it off to the given table settings. Some knock is normal, but 2000 sounds extreme!
Drifting
Joined: Oct 1999
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From: Gloucester Va
Re: Knock counts when starting... (ski_dwn_it)
Yeah, A few knocks will appear at start up on a scanner, but not 2000. You may want to try a different scanner. If they one is bugn out then I wouldn't trust it to tune my car.
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From: Dallas TX
Re: Knock counts when starting... (Glock'94)
I'm using DataMaster. I turn my iginition to on, begin logging, then start the car. It catches anywhere between 1000 and 3000 knock counts when starting.
I hooked up DataMaster to R94-LT1's car and recorded up to 12,000 counts of knock with his spun rod bearing (in just a matter of a minute or so).
Does this sound right, or does it sound like the knock logging counts are being reported wrong?
I hooked up DataMaster to R94-LT1's car and recorded up to 12,000 counts of knock with his spun rod bearing (in just a matter of a minute or so).
Does this sound right, or does it sound like the knock logging counts are being reported wrong?
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From: Dallas TX
Re: Knock counts when starting... (93LT1)
Hmm.. something is screwy with this software then. I picked up thousands of counts of knock from R94LT1's computer, so it's not just my engine. It has to be the software.
How many counts of knock max should the sensors be able to record? (say .. per second?)
How many counts of knock max should the sensors be able to record? (say .. per second?)
Le Mans Master
Joined: Apr 2001
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From: Little Elm TX
Re: Knock counts when starting... (Glock'94)
Hmm.. something is screwy with this software then. I picked up thousands of counts of knock from R94LT1's computer, so it's not just my engine. It has to be the software.
How many counts of knock max should the sensors be able to record? (say .. per second?)
How many counts of knock max should the sensors be able to record? (say .. per second?)
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Drifting
Joined: May 2001
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From: Brandywine, Chester and Ridley Valleys Pennsylvania
Re: Knock counts when starting... (R94 LT 1)
My friend's Z28 :chevy did the same thing, the knock counts would be constantly rolling over into the hundreds then thousands. We figured it had to be false knock (you think?) because it was there at idle with 100 octane race fuel. He put in the LT4 knock module, and problem solved (almost). He still gets some counts, and gets a few degrees of retard, but *nothing* like the way it was.
Next step, I think, is for him to have the computer's tables desensitized. I did this on my L98 and very very rarely got any knock at all (of course I run 1/2 94 and 1/2 100 octane full time)
Do you have headers or a loud exhaust? (Obvious things first, I guess!)
Next step, I think, is for him to have the computer's tables desensitized. I did this on my L98 and very very rarely got any knock at all (of course I run 1/2 94 and 1/2 100 octane full time)
Do you have headers or a loud exhaust? (Obvious things first, I guess!)
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From: Dallas TX
Re: Knock counts when starting... (TrueBlue ChevyDude)
I already am running the LT4 knock module. Only once have I noticed knock go up by less than say 10 counts. Most of the time it goes up by a few hundred. So do you really think this is flase knock? I'm running twice the octane booster I'm supposed to (1 full can to 10 gallons), so I don't think that i actually have any knock. I have only heard one definite detonation...
I don't have headers, but my exhaust is just about as loud as it could possibly be. I wonder if all the resonation could be causing a problem.
Does the knock sensor listen for a specific pattern of firing.. and if it hears a cylinder fire before it's supposed to, it is called knock?
[Modified by Glock'94, 11:20 AM 3/12/2002]
I don't have headers, but my exhaust is just about as loud as it could possibly be. I wonder if all the resonation could be causing a problem.
Does the knock sensor listen for a specific pattern of firing.. and if it hears a cylinder fire before it's supposed to, it is called knock?
[Modified by Glock'94, 11:20 AM 3/12/2002]
Le Mans Master
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From: Sachse Texas
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Re: Knock counts when starting... (Glock'94)
Update your timing to that for a 383 motor and see if you get as much knock. I have always had a problem with false knock since I did a stroker.
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From: Dallas TX
Re: Knock counts when starting... (Vette92)
Update your timing to that for a 383 motor and see if you get as much knock. I have always had a problem with false knock since I did a stroker.
Drifting
Joined: May 2001
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From: Brandywine, Chester and Ridley Valleys Pennsylvania
Re: Knock counts when starting... (Glock'94)
Probably is false knock, although to be sure, you might want to run straight race gas. I know even the NOS---> race octane boost only adds .5 or .7 or something. 93 becomes 93.7, etc.
IMHO, I'd say that it's resonance from the exhaust. If you're running race gas (heck, even 94 Super should suffice, although I remember you saying 92 is the highest in your area) and you're revving the motor in neutral with no load, either there's problems with the motor/programming or it's false knock.
I think the KS just picks up a certain range of frequencies. It doesn't really "poll" the cylinders or look at the firing order, it just sits in the block and reports back to the computer when it senses something which it construes as knock.
This is all pretty basic stuff, not like I have expert answers to offer or anything. But, the basic premise worked on my friends LT1, I'm betting that it's the same cause for you.
IMHO, I'd say that it's resonance from the exhaust. If you're running race gas (heck, even 94 Super should suffice, although I remember you saying 92 is the highest in your area) and you're revving the motor in neutral with no load, either there's problems with the motor/programming or it's false knock.
I think the KS just picks up a certain range of frequencies. It doesn't really "poll" the cylinders or look at the firing order, it just sits in the block and reports back to the computer when it senses something which it construes as knock.
This is all pretty basic stuff, not like I have expert answers to offer or anything. But, the basic premise worked on my friends LT1, I'm betting that it's the same cause for you.
Drifting
Joined: Oct 1999
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From: Gloucester Va
Re: Knock counts when starting... (TrueBlue ChevyDude)
It is normal to get knock couts at start up because of the starting of the engine and what not. They are more or less false knocks. Second I didn't think a engine could sprak knock at idle there is no load. Headers will/can cause flase knock reports. I've read several post with this being a problem. Most have had to turn the knock retard to 0 to prevent timing retard from it. I get knock counts when I rev my engine up in park, or "N" Just a few. I've checked it out and it's false couts from the headers.
The knock sensor to my understand works by picking up a frequency(spelling sorry) range. If it sees this freq. it thinks knock even if it's not. My 97 Saturn had a recall on the knock sensor. The reason being the sensor was set to pick up knocks with in a set freq. range. It just so happens the Engine can put off a freq. within this range. Not all 97 Saturns do. Just like not all Engine pt out the same even with the same parts. So my Little Saturn had no power after 2000RPM. I put in the new sensor and all works well now. It is set to a didfferent freq. range but still able to pick up knocks.
[Modified by 88_vette, 1:42 PM 3/12/2002]
The knock sensor to my understand works by picking up a frequency(spelling sorry) range. If it sees this freq. it thinks knock even if it's not. My 97 Saturn had a recall on the knock sensor. The reason being the sensor was set to pick up knocks with in a set freq. range. It just so happens the Engine can put off a freq. within this range. Not all 97 Saturns do. Just like not all Engine pt out the same even with the same parts. So my Little Saturn had no power after 2000RPM. I put in the new sensor and all works well now. It is set to a didfferent freq. range but still able to pick up knocks.
[Modified by 88_vette, 1:42 PM 3/12/2002]
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From: Dallas TX
Re: Knock counts when starting... (TrueBlue ChevyDude)
Probably is false knock, although to be sure, you might want to run straight race gas. I know even the NOS---> race octane boost only adds .5 or .7 or something. 93 becomes 93.7, etc.
IMHO, I'd say that it's resonance from the exhaust. If you're running race gas (heck, even 94 Super should suffice, although I remember you saying 92 is the highest in your area) and you're revving the motor in neutral with no load, either there's problems with the motor/programming or it's false knock.
I think the KS just picks up a certain range of frequencies. It doesn't really "poll" the cylinders or look at the firing order, it just sits in the block and reports back to the computer when it senses something which it construes as knock.
This is all pretty basic stuff, not like I have expert answers to offer or anything. But, the basic premise worked on my friends LT1, I'm betting that it's the same cause for you.
IMHO, I'd say that it's resonance from the exhaust. If you're running race gas (heck, even 94 Super should suffice, although I remember you saying 92 is the highest in your area) and you're revving the motor in neutral with no load, either there's problems with the motor/programming or it's false knock.
I think the KS just picks up a certain range of frequencies. It doesn't really "poll" the cylinders or look at the firing order, it just sits in the block and reports back to the computer when it senses something which it construes as knock.
This is all pretty basic stuff, not like I have expert answers to offer or anything. But, the basic premise worked on my friends LT1, I'm betting that it's the same cause for you.
Thread Starter
Team Owner
Joined: Apr 2001
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From: Dallas TX
Re: Knock counts when starting... (88_vette)
Thanks for the input 88_vette... I may very well have to turn my max retard down to like 2 or something. I want to be absolutely sure that it's not knock that I DO want retarded.
Drifting
Joined: Oct 1999
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From: Gloucester Va
Re: Knock counts when starting... (Glock'94)
Damn Glock 11.55:1 comp. That's a lot. Gas is only getting worse in quality. I think even LPE is now running his Crate engines at only 10.5:1 when they where 11:1 just a few years ago. You may want to think about putting a thinker head gasket on to lower that some?
Fuel try the local drag track. They usally have it. If not try a local air port. Some of those have high power jucie for the small plans. But hope you have ome extra cash :eek:
Yeah I would make sure the knocks are not before changing the retard.
Wha if you were to set the timing really low so that you know it wouldn't knock due to the timing being so low. If you still get knock counts then you can be/feel pretty safe it's false counts.
Fuel try the local drag track. They usally have it. If not try a local air port. Some of those have high power jucie for the small plans. But hope you have ome extra cash :eek:
Yeah I would make sure the knocks are not before changing the retard.
Wha if you were to set the timing really low so that you know it wouldn't knock due to the timing being so low. If you still get knock counts then you can be/feel pretty safe it's false counts.
Le Mans Master
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From: Sachse Texas
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Re: Knock counts when starting... (88_vette)
11.5 compression on an LT1/4 motor is not all that high. The reverse flow cooling systerm cools the heads first which allows for a higher compression to be run without detonation using the same gas as a traditional motor.
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From: Dallas TX
Re: Knock counts when starting... (Vette92)
11.5 compression on an LT1/4 motor is not all that high. The reverse flow cooling systerm cools the heads first which allows for a higher compression to be run without detonation using the same gas as a traditional motor.
Obviously higher than 91 octane is what i prefer, and in Dallas they have 93, so I'll be fine once I move back there.
