What symptoms does an unbalanced pulley create
08-19-2003, 12:12 PM
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Re: What symptoms does an unbalanced pulley create That's a spooky question. KR isn't, by nature, isolated to a given RPM. It's caused by detonation in the motor, or a vibration that the sensor picks up. If you're experiencing true KR from a lean A/F ratio, detonation could occur at any RPM. However, in my experience it does most often occur above 5k in these cars.
I assume the reason you're asking about the pulley is because you're trying to determine if the pulley is causing "false knock." To answer your question, yes, an unbalanced pulley can create a vibration the PCM will interpret as detonation, and KR will result. Also, assuming that it is false knock from the unbalanced pulley, who's to say at what RPM the vibration would occur? Take your tires for instance.. They do crazy things when out of balance. They can vibrate at 70mph, but smooth out by 85mph, then vibrate again at 120mph.
To be honest with you though, I would consider your ported MAF to be more suspect. Borrow a stock MAF from a buddy one day. Install it on the car, reset the PCM, and go put some miles on it. Autotap the car at WOT and observe the results. As far as troubleshooting is concerned, it's much easier to loosen a few hose clamps in your intake tract than it is to torque that damned crankshaft bolt to 230 ft/lbs.
I assume the reason you're asking about the pulley is because you're trying to determine if the pulley is causing "false knock." To answer your question, yes, an unbalanced pulley can create a vibration the PCM will interpret as detonation, and KR will result. Also, assuming that it is false knock from the unbalanced pulley, who's to say at what RPM the vibration would occur? Take your tires for instance.. They do crazy things when out of balance. They can vibrate at 70mph, but smooth out by 85mph, then vibrate again at 120mph.
To be honest with you though, I would consider your ported MAF to be more suspect. Borrow a stock MAF from a buddy one day. Install it on the car, reset the PCM, and go put some miles on it. Autotap the car at WOT and observe the results. As far as troubleshooting is concerned, it's much easier to loosen a few hose clamps in your intake tract than it is to torque that damned crankshaft bolt to 230 ft/lbs.
08-19-2003, 01:23 PM
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Re: What symptoms does an unbalanced pulley create I have purchased the MAF sensor ends this morning and installed it at lunch. I also reset the PCM at lunch and when i go home tonight i will atap the car to see if I am still having issues. Hopefully it isnt my pulley (SLP) because I hear ASP pulleys had that problem once time or another
