Great answer Shane. You know I was only playing with you. I appreciate the
intelligent answers from you guys. I learn as much from you as you learn
from each other, in fact, probably more, because I knew less than you to
start with. Keep up the good work.
Ron
00 PB SLT QC 4X2 5.9 46RE 3.92 LSD
For modifications see my DML Profile (URL follows)
http://www.twistedbits.net/WWWProfile/dakota/Kw9pV1EkFeOYY
-----Original Message-----
From: owner-dakota-truck@buffnet.net
[mailto:owner-dakota-truck@buffnet.net]On Behalf Of Shane Moseley
Sent: Monday, January 29, 2001 1:12 PM
To: dakota-truck@buffnet.net
Subject: Re: DML: Gas mileage to crap?
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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