Re: [alfa] RE: Motronic fuel quality switch

["Dean W. Cains" <dwc@xxxxxx>]

Hi Jonathan:

I can't speak about the Motronic adjustment on your '92 Spider, but on my 
'88 BMW M3, that little switch made a huge difference.  On the default 
setting the engine would idle roughly and had a midrange flat-spot that was 
exacerbated by the A/C (I'm in S. Florida).  Moving that switch to the #2 
position made the idle smooth as glass and fixed the flat spot, but the 
biggest difference came during the throttle blip of a double-clutch 
downshift, which I didn't even know was a problem until it was "fixed".  I 
don't think you can hurt anything, so why not flip the switch to the 1 or 2 
position, and see what you think?  If the additional fuel doesn't fix the 
pre-ignition trouble, maybe try position 5 or 6 to get the few degrees of 
retarded timing, too.  The difference may not be what you'd get from a new 
chip, but it's easy to try, and of course, the price is right.  Also, make 
sure you've got the proper spark plugs installed, or try a set with a 
slightly colder heat range.  I'd be careful about letting that pre-ignition 
continue.  I once holed a beautiful custom-made 11:1 Jahn's piston in my 
XKE back in the late 70's, as I didn't think a little pinging was anything 
to worry about.

Regards,

Dean
Lutz, FL
'74 & '87 Spider Veloce's


At 12:10 AM 5/5/2004, you wrote:

> Date: Tue, 4 May 2004 09:29:06 -0700
> From: Jonathan Thames <jthames@domain.elided>
> Subject: [alfa] RE: Motronic fuel quality switch
>
> Some very knowledgeable lister mentioned this miracle switch in a post last
> week.  Does it have any effect on power?  I did a Google (NYSE: ??) search
> on Motronic FQS, and had a couple Porsche hits, but none for Alfa. The Alfa
> Factory manual, which I have, doesn't mention the FQS switch. Some Porsche
> digest page from the 1990s show the following  seven switch positions (sorry
> if the formatting is screwed up):
> Switch Position  Fuel Correction  Ignition Correction
> 0 (stock)                       0                       0
> 1                               +3.1%           0
> 2                               +6.3%           0
> 3                               -3.9%           0
> 4                               0                       -2.790
> 5                               +3.1%                   -2.790
> 6                               +6.3%                   -2.790
> 7                               -3.9%                   -2.790
>
> If these values hold true for the Alfa, which could best serve to alleviate
> moderate pinging under say 33% load? It pings less under full load, and
> drivability is fine. Would changing these settings provide more HP, as would
> a chip? If so, what would give the most increase? Thanks!
>
> Jonathan Thames
> 1992 Spider
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