bernd@texas.net wrote:
> Now now Ron.
>
> Shane is a person that I respect and he has his own data that he collects.
> I've got no quarrels with him and don't need to start any either.
Thanks Bernd - and I echo the same for you. Have to admit that I might have
trolled a bit with the "bet" thing. I've had a customer piss me off already today
and shouldn't let those frustrations out here.
> On the data, I have mine as well. From all the trucks i've played with
> (tested), the O2 was not the determining factor for OPEN-LOOP. MAP, TPS, and
> Coolant Temp are the deciding factors. There's no way around that.
>
> ** Cold engine (cold temperature) = OPEN-LOOP
Mostly agree here as cold is relative. For example, I can start my truck in 10
degrees F on one day and on another day I might start it in 110 degrees F. When
the truck first starts - it will be in Open-Loop regardless of whether I started it
in 10 degree F or 110 degree F weather.
> ** Warm-Up (driving to warm up the engine) - at 140-150 degrees, it kicked into
> CLOSED-LOOP
This transition from Open-Loop to Closed-Loop may have actually happened - I am not
challenging this. A transition from Open-Loop to Closed-Loop ALWAYS occurring at
140-150 degrees IS EXACTLY what I'm challenging. For example, if I started my
truck in 10 degrees F one day - do I have to wait until the motor gets to 140-150
degrees before the transition? I think NOT. Compare this to if I started my truck
in 110 degrees F - it should transition very rapidly. This is NOT the case though.
My findings indicate that both trucks will transition at almost the EXACT same time
- give or take a couple of seconds. This is due primarily to the fact that our O2
sensors are of the self-heating variety. I can even tell you within a second or
two EXACTLY when it will transition by looking at O2 sensor voltage ONLY. This
works every time with NO exceptions.
> ** Warm Engine (cruising) = CLOSED-LOOP
>
> ** Warm Engine (WOT) = OPEN-LOOP (starts at about 3/4 throttle to boot when MAP
> is right about 2"hg.)
It looks like you have found the delta-TPS transitions - I agree they are there.
> I can simulate the TPS and MAP signals using some test equipment I have but the
> easiest test i've done is at a warm-idle (CLOSED-LOOP). I forced the MAP to
> 3.8v and low-and-behold...OPEN-LOOP. (Didn't touch the TPS, IAT, CTS, or O2.)
> I also disconnected the rear O2 and checked the status (still warm-
> idle)...check engine light but CLOSED-LOOP.
It is true that a rapid change (delta) in TPS or MAP will induce a transition from
Closed-Loop to Open-Loop (and vice-versa). This is due to "driveability"
concerns. Think of it like a carb's "pump-shot". Without that rapid delta-TPS
transition to Open-Loop (richer mixture) the truck would bog. There are lots of
these driveability transients happening all the time. When I talk about the O2
sensor causing the transition from Open-Loop to Closed-Loop - I am referring ONLY
to the cold-start condition and the FIRST transition from Open to Closed-Loop.
You are right that there are lots of other transitions that are related to
delta-TPS and delta-MAP (among others?) but I've only noticed an extremely
consistent behavior at the initial cold-start transition.
> Sure the FSM's have their definitions of OPEN/CLOSED-LOOP, but from what i've
> seen/tested...the O2's have little effect on switching to OPEN-LOOP.
>
> - Bernd
>
> > <shuffle shuffle> ....donning asbestos suit....<ugh lug lug> donning
> > bullet-proof vest <clomp clomp> ...walking into lead-lined room (to ward
> > off kryptonite rays)...ahhhh...get comfy...ok, guys....let the fireworks
> > begin! ;-D
Normally you would be correct here - but I think Bernd and I can demonstrate how
much info can be gleaned from a positive argument 8-)
Latr,
Shane
-- '96 IndyRam-HisIndy-MPI/TB/Pulleys/AccelCoil/MPComp/HookerSuperComps/CompTAs '96 IndyRam-HerIndy-numbered(#142)"Track Truck" '74 Triple-Black Dodge Challenger Rallye 360 home-brew EFI R&D vehicle '68 Black Corvette Convertible 427 (For Sale)
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