Help Knock from nowhere (long)
Help Knock from nowhere (long) Over the past few months of watching how my car has been acting w/ A-Tap my numbers were actually pretty good being i have the 98 computer w/ knock issues. i was pulling Max 2.6* of knock and 24-28* of timing throughout the 1/4 mile. the car felt down on power a little so i checked and replaced all my pushrods due to some bent ones. I also replaced the springs w/ a set of 918's since i am swaping in a new cam soon. Tonight a took my car out and ran A-tap and was shocked at what my numbers went to. first run i was pulling 2.8*-3.9* of knock and it brought my timing way back to 19. I was shifing around 6000 (factory limit yet) my next run when I was short shifting it arounf 5600 i had minimal knock (2.5* +/-) but definitly knew the car was slower due to the short shift. I'm thinking i might open up the valve covers and go over the rocker arms again to see if any are loose which could cause some knock maybe. All my pipes are tight so i doubt it to be false knock other than what usually shows up. i dont know does anyone else have any suggestions for me to try. Thanks for taking the time to read this and for any help.
JR
JR
Re: Help Knock from nowhere (long) Ditto on the knock sensors.
You should take some steps to see if it is false knock (if you haven't already). Basically, add some high octane booster, or retard timing to something like 15 at WOT and see if the KR goes away. If it doesn't, then you are going to have to address the false knock.
Either replace the sensors with a newer version, or you can also try wrapping the threads of the KR sensors with some teflon tape (sometimes works).
Good Luck
You should take some steps to see if it is false knock (if you haven't already). Basically, add some high octane booster, or retard timing to something like 15 at WOT and see if the KR goes away. If it doesn't, then you are going to have to address the false knock.
Either replace the sensors with a newer version, or you can also try wrapping the threads of the KR sensors with some teflon tape (sometimes works).
Good Luck
Re: Help Knock from nowhere (long) False KR via the 98PCM KR bug, upgrade to newer sensor model. Read the discussion on the other board.
NoGo, do you agree if injectors are maxed or overmaxed you can get knock from the fuel being heated? I think I have this problem. 83+% at only 5000rpms and I spin to 6300-6600, and the KR seems slight but its there and only in the higher rpms. Also tried racegas and reduce timing still there... TIA
Charlie.
NoGo, do you agree if injectors are maxed or overmaxed you can get knock from the fuel being heated? I think I have this problem. 83+% at only 5000rpms and I spin to 6300-6600, and the KR seems slight but its there and only in the higher rpms. Also tried racegas and reduce timing still there... TIA
Charlie.
Re: Help Knock from nowhere (long) I'm gonna go order the 99+ sensors here then. I need the harness also right? i read that you have to cut the old one and wire in the new one because the connectors between the sensors are different. Later this week I will go down the the local Sunoco and get some 100 octane and run some logs w/ that. rigth now i dont have a way to do the timing retard so i'll do what i can for now.
JR
JR
Re: Help Knock from nowhere (long) Heating the fuel too much is not going to contribute to KR. It is actually going to reduce the odds of fuel induced KR. Fuel induced detonation is the result of fuel droplets forming at injection. A poor injector, or overly rich condition can cause this.
Heating your air charge too much....now thats a different story.
In order to determined whether or not your injectors are causing KR, you have to get a wideband hooked up. Maxed injectors will only contribute to KR via a lean condition. If your car is going lean past 5000 rpms (due to your injectors, and not a tune) then, yes, your injectors are inducing the KR via a lean condition.
Most likely, your KR is not your injectors (343 HP is not going to max the stock injectors). High RPM KR independent of fuel octane can be induced by your car burning oil, poor spark, hot spark, cylinder carbon buildup, or too high compression. Additionally, it could be false KR.
Good Luck
Heating your air charge too much....now thats a different story.
In order to determined whether or not your injectors are causing KR, you have to get a wideband hooked up. Maxed injectors will only contribute to KR via a lean condition. If your car is going lean past 5000 rpms (due to your injectors, and not a tune) then, yes, your injectors are inducing the KR via a lean condition.
Most likely, your KR is not your injectors (343 HP is not going to max the stock injectors). High RPM KR independent of fuel octane can be induced by your car burning oil, poor spark, hot spark, cylinder carbon buildup, or too high compression. Additionally, it could be false KR.
Good Luck
