[Diy_efi] Chevy / Jaguar conversion spark knock

[Jack Vines]

Greetings, All,

Conventional wisdom is it is bad science to set so much advance the knock
sensor is activated.  When the sensor signals knock, the software pulls out
a bunch of advance and puts it back in slowly.

thnx, jv. 

-----Original Message-----
From: Jeff Behrens [mailto:jwg94 at yahoo.com]
Sent: Thursday, May 29, 2003 7:32 AM
To: List for general do-it-yourself EFI talk
Subject: RE: [Diy_efi] Chevy / Jaguar conversion spark knock


I owned a 91 gmc truck tbi that called for 0 base
timing.  I ran 8 ahead of base without any problems. 
Are you running a knock sensor?  It should take out
any knock problems due to predetonation.  I purposely
set my timing to 18 ahead to test it and it corrected
fine.


Jeff
--- Mike Worley <Mike.Worley at cae.com> wrote:
> 
> Since I didn't have the Camaro under hood decal that
> specifically sited
> the base timing, I was depending on other feedback I
> got from the Web
> that the base timing should be 0 deg, ( set timing
> connector opened up.)
> I have not attempted using any aftermarket chips or
> reprogramming the
> timing maps, etc. First I just need to get it sorted
> out stock so I know
> where I am starting from.
> 
> Why would your S10 have reduced knock with base
> timing advanced more
> than spec? Doesn't that skew the entire timing map
> up causing more
> knock? That doesn't sound right. 
> 
> Does anyone have the definitive answer as to what
> the base timing should
> be for a 1991 Camaro 305 TBI?  Understandably there
> doesn't seem to be
> much interest in the TBI Camaro.
> 
> Thanks,
> Mike  
> '67 Jaguar 420 (no EFI here!)
> '86 Jaguar XJ6 (Lucas/Bosh EFI)
> '88 XJS convertible (Chevy 305 TBI)
> '02 Yukon XL 
> 
> 
> 
> -----Original Message-----
> From: Scott Pearson
> [mailto:mrcad472 at iowatelecom.net]
> Sent: Thursday, May 29, 2003 9:34 AM
> To: List for general do-it-yourself EFI talk
> Subject: Re: [Diy_efi] Chevy / Jaguar conversion
> spark knock
> 
> 
> When you're changing the base timing, are you also
> changing it in the
> EPROM?
> I had a 305 powered S10 in the other day that had
> the base timing set at
> "0", set it to the 6 deg advance that was specified
> and the knock went
> away.
> 
> - Scott
> ----- Original Message -----
> From: "Mike Worley" <Mike.Worley at cae.com>
> To: <diy_efi at diy-efi.org>
> Sent: Wednesday, May 28, 2003 12:27 PM
> Subject: [Diy_efi] Chevy / Jaguar conversion spark
> knock
> 
> 
> > I have been struggling with a resolving a spark
> knock in my now Chevy
> > powered Jaguar convertible.  The engine and
> computer / harness is from
> a
> > 1991 Camaro.  Its a 305 TBI.  Even running at
> -4deg retard base timing
> I
> > still have spark knock upon even light
> acceleration (when warm).  The
> > sensor doesn't seem to catch it.  There are no
> error codes showing up
> > and I do seem to have some RPM drop when doing the
> bang on the block
> > test.  I wanted to remove the sensor but due to
> the close quarters I
> > cannot seem to break it free.  Its stamped steel
> construction doesn't
> > lend its self to much muscle and every thing seems
> to slip.  I have do
> a
> > spare and was wondering if there is alternate spot
> to mount it on the
> > Chevy block or intake???  I guess what's more
> important would be why
> is
> > knocking in the first place...  The engine runs
> strong, is tight, good
> > compression and only 45K miles.   Does anyone have
> the correct part
> > numbers for the sensor and associated signal
> conditioning amp for the
> > 350 TBI engine.  I want to make sure the right
> parts are installed.
> >
> > Mike
> >   _____
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> 
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