[s-cars] loss of power

[Elijahallen92 at aol.com]

In a message dated 6/28/2004 3:52:51 PM Eastern Standard Time, 
robert at s-cars.org writes:


> Some cars have 1 some 2.  My urS6 has two and probably yours does as well 
> but I can't make a firm statement on that for you.  I think it varies from I-5 
> to I-5 model year but I haven't researched it to be sure.
> 
> I have experienced this KS timing back-off.  It just simply ain't no fun 
> 'tall.  It feels like the car just died.  It runs and will SLOWLY accelerate and 
> will pick up significantly better if you back off a bit and relieve the 
> conditions causing knock.  Once it accelerates into higher rpms the ECU 
> automatically backs off the boost some and the tendency for knocking is reduced and 
> you can accelerate more or less normally.
> 
> The stock ECU uses a knock sensor timing map which, when activated by the 
> detection of knock, cuts the timing back from quite a bit of advance to 
> essentially zero advance.  That is an absolutely horrid thing to experience when you 
> are pulling out to pass a slowpoke before oncoming traffic closes off your 
> opening.
> 
> What causes knocking?  Heat.  Poor fuel.  Too high boost.  Carboned up 
> internal parts acting as a source for preignition?  Partially plugged intercooler 
> not removing heat rapidly enough (blasted dead bugs!)?  Something else?
> 
> Is this what's happening to you?  I dunno but it's a halfway decent guess - 
> maybe?
> 

Sounds like the same thing but its 65 out today and so heat soak is not an 
issue. I have tried different fuel, all 93 octane so I don't think thats causing 
it. Chips are written for 26psi and unless I have 100octane it rarely gets 
above 26psi (on 100 octane it builds to 28 to 32 psi with no issues. Carbon on 
internals might be an issue. If I drive normal for days at a time and then do a 
2nd gear WOT to redline I get a pretty good amount of black smoke but after 
doing it a couple times it goes away. So, where are the knock sensors? I guess 
I'll replace them and go from there. Thanks for the help.

Elijah