Spark retard
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 810
Likes: 4
From: Austria
Spark retard
hi
i burned a matching chip for my engine, but i get spark retard under certain conditions...eg when hitting the gas...
i also ´hooked up datamaster on a stock engine, and it also shows the retard under the same certain conditions..the amount im dealing with are about max 5°
can i assume this is normal?
i dont hear knocking or pinging....
thanks
i burned a matching chip for my engine, but i get spark retard under certain conditions...eg when hitting the gas...
i also ´hooked up datamaster on a stock engine, and it also shows the retard under the same certain conditions..the amount im dealing with are about max 5°
can i assume this is normal?
i dont hear knocking or pinging....
thanks
Melting Slicks
Joined: May 1999
Posts: 2,037
Likes: 0
From: Sarasota FL
Re: Spark retard (corvette90)
You can't always hear it. It could be real and could be damaging your engine. It could be caused by too much timing, not enough fuel, carbon build up, no EGR, or a myriad of other things. Check your plugs after knock to see if there a little black/silver flecks of aluminum on them.
Or, it could be false knock.
I wouldn't consider it normal, try to figure out if you're really knocking and then get rid of the knock so you don't damage anything.
Or, it could be false knock.
I wouldn't consider it normal, try to figure out if you're really knocking and then get rid of the knock so you don't damage anything.
Drifting
Joined: Jun 2001
Posts: 1,625
Likes: 1
From: Zagreb, Croatia
Re: Spark retard (Aaron's 87)
You can't always hear it. It could be real and could be damaging your engine. It could be caused by too much timing, not enough fuel, carbon build up, no EGR, or a myriad of other things. Check your plugs after knock to see if there a little black/silver flecks of aluminum on them.
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 810
Likes: 4
From: Austria
Re: Spark retard (Sliding)
in the shop manual, it is also said, that the ecm sometimes advance timing until it hears a knock..this is done, to prove the knock sensor
also a forum member stated, it is normal that the ecm advances spark to the max amount to get max power..and then reduces..
any opinions
also a forum member stated, it is normal that the ecm advances spark to the max amount to get max power..and then reduces..
any opinions
Melting Slicks
Joined: May 1999
Posts: 2,037
Likes: 0
From: Sarasota FL
Re: Spark retard (corvette90)
I've heard that, but never seen it happen. Anyway, it wouldn't keep inducing knock. EGR is exhaust gas recirculation, an emissions function that also cools combustion temps.
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 810
Likes: 4
From: Austria
Re: Spark retard (Aaron's 87)
ok..thank you for your answers..but, what to do now..
should i retard the timing at the point where knock occur, or...
my concern is, that i retard timing so far, that no knock will occur, but also no power ( or less)
i also doubt, that i can get completely rid of the knock counts....
any opinions
thank you
should i retard the timing at the point where knock occur, or...
my concern is, that i retard timing so far, that no knock will occur, but also no power ( or less)
i also doubt, that i can get completely rid of the knock counts....
any opinions
thank you
Melting Slicks
Joined: May 1999
Posts: 2,037
Likes: 0
From: Sarasota FL
Re: Spark retard (corvette90)
Yes, pull out timing where knock occurs AND before knock occurs. When you're more comfortable tuning, you can also change how much timing can be taken out, how fast it's taken out, and how fast it comes back.
My enginge doesn't knock unless carbon has built up. The knock sensor doesn't hear it, I don't hear it, and the plug don't show it. You CAN tune it out if your engine is in good working order.
Generally, you have at least a couple degrees of advance between peak power and knocking, but every engine is different. The only way to know is through testing. I guess you could use ion sensing, but that's too far in the future for our ECMs.
My enginge doesn't knock unless carbon has built up. The knock sensor doesn't hear it, I don't hear it, and the plug don't show it. You CAN tune it out if your engine is in good working order.
Generally, you have at least a couple degrees of advance between peak power and knocking, but every engine is different. The only way to know is through testing. I guess you could use ion sensing, but that's too far in the future for our ECMs.
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