Re: CIS-E fuel modification @ WOT

[ejfluhr@austin.ibm.com (Fluhr)]

> Sorry don't have to worry about CIS-E III on JT engine :)

Yup, it makes life a bit easier for those of us with CIS-E.  However,
if this mod works reasonably well, I am sure there will be many listers
who will want to adapt it to their 2.3L CIS-E III engine.  We might as
well try to figure this stuff out to cover as many N/A engines as
possible.

> >Also, you might have to be careful with tripping the WOT switch at
> >low rpms ( < 3000?), since the mixture may be too rich for the car and
> >cause the engine to bog.
> You could re-calibrate the position of the switch to close later. Or how
> about a 2 stage switch with different resistors. Or digitally programmed
> resistors using PIC... nahh was supposed to be easy.

You would have to monitor RPM and kick in the higher resistance once you
have reached a higher RPM level, otherwise it wouldn't work.
 
> Certainly would.  TAP lists that +10 HP chip in their ads, but when I asked
> him about it, he said there was none.

OK.  Seems rather unethical to me to sell the chip if it really provides
no improvement, but... <shrug>
 
> I think Bentley troubleshooting procedure calls for 15K shunt inserted into
> ecu plug and you were supposed to see 40 to 80 mA (sorry, values off the
> top of my head) to the diff press reg.

Ok, so are you assuming that the temp sensor/ECU maintains a linear (or
similar) relationship between resistance and increase in PA current, so
that the more resistance you add (up to a point) the greater the increase
in PA current?

Suppose a 15K resistor flags a fully-cold engine, so the ECU adds 80mA
of current to enrich the mixture.  You are hedging on the fact that
a 2K Ohm resistor (for example) may produce a 10mA increase in PA current.
It is certainly an interesting gamble, and sounds reasonable.  Is Bruce
going to measure the PA current increase when the relay switches?
 
Later,
Eric