Replaced Dist ign system with SDI system, and computer running very different

[Roger Heflin]

On Sun, 9 Aug 1998, Bruce Plecan wrote:

> From: Roger Heflin <rah at horizon.hit.net>
> Subject: Re: Replaced Dist ign system with SDI system, and computer running
> very different
> 
> >I am going to have to see what the gas mileage.  Does anyone know if
> >having the timing changed would cause this kind of differences in fuel
> >usage?
> 
> If the improvements are enough to be reflected inna lower cruise
> TPS, then I'd expect to see a change.  Now, with that being said,
> if the BL/INT changes alot then it may not be so much.  Low cruise
> gets quite complicated when ya mix in BL/INT IAC counts.
> 
> Your setup, does it use a crank attached disc?
> With Hall effect switches?,
> Does the module look to be a gm unit like off a v-8 caddy?.
> Matter of fact are there any numbers showing on things?.
> Curious minds and all
> Cheers
> Bruce

There were not numbers showing on the thing.  It is a crank trigger, with 
a magnetic sensor.  The trigger has slots every 6 degrees, and it has a
area where there are no slots for 4-6 teeth.  You can see a picture of
the wheel in question at:  http://www.electromotive-inc.com/Camaro.htm
There is a picture of exactly the wheel I have in these directions.  This
is also the full directions for the installation of the part.

I found some stock injector idle runs.  Stock the car was idling with
2.5-2.6 ms on a 22 lb injector.  The current injectors are rated to be 30 
lb at 39 psi (the old were 22 at 45) so at 45 the current injectors should
be rated around 34.5 lb/hr.  Before my idle was running 2.1 at idle which 
is more gas than I was using with the old injectors, so something was
off.   Quick calculations (2.1*22/34.6 = 1.3 so based on this to have the 
same amount of fuel it would need 1.3 with the current injectors rather
than the 2.1 I had.  The idle is boosted over what it was so it probably
needs more than 1.3, and the computer seems sure it needs less than 1.7
which is I guess about right.  With the block learns and integrators where
they are need to work on the computer.  The gas mileage should be better
with it running that much less gas.   I should know by the end of the week
if the mileage is better.

			Roger
			93 Z28