Knock with PP & ALKY?


Active Member
May 23, 2001
ALKY & Power Plate and I still have part throttle knock 4.5 - 8. WOT knock 3 @ 20psi.
Alky turned low - highest pump speed.
Changed MAF sensor, no change.
Turned alky off, added 104 octane. No part throttle and no WOT knock!
Fuel goes up with boost.
Ideas on why I have this knock & possible cures.

You have the alcohol coming on low and at the highest pump speed? Try raising the spray on point.
I am getting part throttle knock before the alky comes on.
I think if I can figure out why the part throttle problem, the car can be tuned when the alky comes on. By adding the 104 ocatne, the part throttle knock went away.
Last year before putting the car away, I was set at 13-14psi alky turn on point, with 70% pump speed, fuel pressure 44 line off, and had no knock at 19 psi. Still was barely rich (808 O2). Might try those settings; it took a whole lot of trial and error to find that spot.
OK, 2 things come in mind. #1, What is your spray on point? #2, When you say part throttle, do you mean like 1/2 throttle and your at say 5-8 #'s of boost and your alky is just turning on? The reason being "IF" your alky is coming on at 1/2 throttle pushing 5-8 #'s of boost, then your problem is that when the alky activates at half throttle, it's drowning out your motor and will cause it to rich knock. I have the same problem too. Your gonna half to be either under the alky spray on point or your gonna have to be on it balls to the wall. Thats the only thing wrong with the alky kits. There is no good driveability under moderate boost levels like 10-15#'s of boost. I was thinking there should be a tps reading to the SMC kit that way there would be a lower pump speed under moderate boost. That would be cool. Now, the next thing on my mind is, I did receive the wrong PP the first time around. Are you sure that you received the correct PP for your plenum? Next is, During your part throttle, what is your 02's reading? Do you have a functioning EGR? Or one at all? I know EGR functions under part throttle. If you haven't checked your EGR in along time and you have high miles, then at least pull it, install a vacuum pump and see if it holds vacuum and clean out the EGR passages in the head with a TON of carb cleaner and let sit, then go back and dowse it again. Then go and beat the crap outta your car to blow out all the built up carbon.
I will look into the EGR. It is supposed to be working.
The alky light does not show to be armed when I am getting the knock.
i do not know the differences in Power Plates but it had the place to drill out the EGR.
You might call Steve Chulpsa Monday, and ask him about that light. He may have some tests you can do to find out if it's working properly. If not, he will fix it; he is great!!!! Can't say enough good things about him.