co adjustments and o2 voltage (was high compressionmotors in 4kqs)

[Huw Powell]

> my DPR current is now between 9.6-12 fluctuating after the adjustment, i
> guessed and went a tad richer.

that's leaner, sort of...

> the idle seems a little rough but i've got to go to 'lil sisters HS grad so
> i'll probably monitor o2 voltages later.
> it seemed to stabilize the 02 voltage closer to .6 while cruising now. i
> thought a richer mixture would make a higher voltage.

I guess it's time for a bit of CIS-E 101.

But first, since your engine is far from "stock," as a hybrid with mixed
parts from different engines and a lumpy cam, it's not going to run as a
"duplicate" of simple engine swaps.  You'll have to chase the operating
parameters that work for it, just like you are, by trial and error.  It
helps if the trials are fairly well informed, of course.

Let's ignore the cold start and WOT conditions for a moment.

when the engine is warm, from idle to about 2/3 throttle, there is a
feedback loop created between the OXS and the DPR.

The OXS, of course, reads the oxygen in the exhaust and tells the ECU
whether the system is a tiny bit lean or a tiny bit rich.

The DPR adjusts the amount of fuel up and down relative to the "static"
setting, which is what you change when you alter the position of the
little 3mm thing in the fule dist.

Under these conditions, changing the fuel dist static mixture DOES NOT
change anything, until you are so far out of range that the ECU/DPR
cannot compensate.

if you turn the screw CW, allowing a richer static mixture, you will see
the DPR current go down to compensate, and vice versa.

With the OXS plugged in, you should see it's output voltage fluctuate
from about 300 to 700 mV and back again, every few seconds at idle, and
maybe faster on the road.  In sync with this! the DPR current will also
fluctuate, ideally from about 8 to 12 mA and back.

If the DPR is not cycling like this, something is wrong.  Something
basic, not really part of the engine swap, like a sender, wot or idle
switch, or ground problem.

outside these considerations:

under cold start and WOT conditions, the static fuel mixture matters
more because the ECU is not reading the OXS, it is using a fixed fuel
setting at the DPR.  So making the static mixture richer (lower warm
idle current at DPR) will enrich the mixture when the engine is cold and
at WOT.

So I'd say, get back to basics, go through all the little things that
have wires running to them, and verify that they are indeed functioning
correctly.  The Bentley has the specs for all these doohickeys, sure,
some may be on my site, but those old 4k/coupe manuals are pretty cheap
these days, used.  And the "used" ones have often never been opened (my
90Q one wasn't).

Good luck!

--
Huw Powell

http://www.humanspeakers.com/

http://www.humanthoughts.org/