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Re: I think I've got engine knock at boost.. I'm stumped! Posted by vvack0matic [Email] (#1443) [Profile/Gallery] (more from vvack0matic) on Mon, 28 Aug 2006 11:08:20 In Reply to: I think I've got engine knock at boost.. I'm stumped!, RM '86 SPG (Vancouver BC), Mon, 28 Aug 2006 00:22:37 Members do not see ads below this line. - Help Keep This Site Online - Signup |
after reading your post im under the impression that your motor is upgraded or tweaked with all the goodies,
what im getting at is how far dose the tweaking go, is the knock sensor over ridden and the wastegate closed tight so it can not open under any psi.
.. if the knock sensor was over road or the wastegate locked down so the motor could not release boost
for lets say ... a valve knocking... bad gas... spent plug, what-ever caused the knock may have took a toll on one of your valves, that is if the motor was locked down, and restricted from releasing boost.
if all was left alone the sharp metal sound may go as far as a bad pump bearing wheel, may it be the water pump, steering pump, alt. look at your belts and see if there overly tight, just know an overly tighten belt gets tighter when the motor is with-in its boost pulling hard hp.
i`d think if the bearing was about to blow in any-belt wheel it will show by taking the belts off and just by hand the wheel will flop around.
alternators are a prim example of its bearing about to blow from over tightened belts, and with the saab motor there are two belts running over its wheel taking a toll on the alt. bearing,
this would make more of a grind sound not a ping, however if a bearing was totally gone the wheel would jump on its axle making the metal ping but more like a bang, bang,... and would be able to get louder than the motor revs seeing how the alt. or any belt wheel is at the firewall.
the clicking from the apc can in no way get louder than the motor for you to hear it in cab.
if the alt. is bad it can arc within - itself or the wires on the back can arc to a ground making a pop louder than motor revs.
as for a metallic sound... a failing bearing or pump.
if the motor was tweaked, and knock sensor over road, or wastegate locked down, i`d say it was a valve.
posted by 24.249.3...
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