Helping a dead one

So this afternoon, I'm cruising up I-93 through heavy but moving
traffic, and spotted a silver Prius that just pulled into the
dead zone in an on-ramp merge with its flashers on. Oops, I
thought, I wonder what's wrong.. I didn't have the leeway to
stop right there but since it was between a pair of interchanges
reasonably close together, I decided to loop around and see what
was up.
.
So I started my nice long WS glide toward the next exit, took
a leisurely path through the routing needed to get me going the
other way on the interstate, and tooled back to the previous
interchange ... Prius was still there on the other side as I
went by, so clearly having an issue. After another leisurely
180 I started into the on-ramp just after where the dead Prius
was but hit the 4-ways and slowed down at the end of it to
drift onto the merge triangle [corrugated concrete, blech] to
stop and then back slowly up far enough to be in a safe stopping
place. No need to hurry through any of this or be abrupt in
my driving behavior -- nay, I *hypermiled* my way through all
of that routing to get back to where this other car was, because
what you do in on-ramp and off-ramp accel and decel is where
some huge gains can be made. Hardly used the brakes at all.
Many people succumb to the temptation to start all kinds of
useless abrupt behavior in cases like this because they get
into some twisted thinking that they're in such a hurry. Taking
it easy maybe got me to the location what, 20 seconds later
than endangering everyone around me would? BFD, this poor
owner wasn't going anywhere for a good long time. As I did a
nice long predictable slowdown, WITH flashers going, toward the
end of the on-ramp and clearly heading for the dead zone, this
butthead in a Cherokee of course made a big deal about finally
blasting by me on the right because drivers around here are just
plain intolerant of anyone else's navigation needs. Screw him,
if I was an AAA flatbed with big yellow flashers he'd probably
behave in the same ersatz-self-important manner.
.
Anyways, I got out and trotted back to this other Prius, where
the owner was deep in several phone conversations at once and
juggling AAA and her sister and the state police all via
call-waiting. But I quickly made it clear that I was there
to try and help and one of the benefits of Prius ownership is
that you get this community along with it, and proceeded to try
and diagnose why her car had suddenly just lost power.
.
Well, it seemed to be the classic "engine does not start" case,
which is often misdiagnosed because of the high crank rate given
to the engine by the motors during a restart attempt. With the
rush-hour highway noise next to us it was almost impossible to
hear what the ICE was doing, but after rebooting the electronics,
the car tried to spin the engine again but it didn't sound/feel
quite right. It in fact sounded just like mine did when I was
doing my pull-the-fuel-pump-power experiments last year just to
see what the responses were.
.
Nonfunctionality of the engine was confirmed by letting it try to
spin up while in Park, and then shifting quickly to Neutral which
should have let it just idle if it was running by then, but instead
feeling it lurch and die. Nothing looked amiss under the hood --
fluid levels okay, nothing hanging loose, etc. I went around and
wiggled/reseated various connectors that I could reach -- ignitor
plugs, crank sensor, MAF/IAT plug, etc, and tried once more and it
wouldn't go. Felt like a no-fuel problem, even though she clearly
had above half a tank. A voltmeter showed her 12V nice and solid
at 12.5, so that wasn't the problem. The throttle motor was working
fine, holding the flap at the right place and not stuck. Without a
scantool there wasn't much else I could do to diagnose the thing,
especially with trucks barreling by at 70 MPH. What I *did't* do
was get under the dash and check the ECU plugs, which in hindsight
I should have at least looked at.
.
AAA showed up with a flatbed shortly thereafter, and I had her
power up to IG-ON and put it in Neutral for them because I was
relatively sure that they wouldn't be able to handle that. While
they *have* dealt superficially with Priuses before they probably
aren't aware of the differences and subtleties of IG-ON vs. READY.
With her HV battery down to one bar and the "main battery" warning
icon already showing up on the MFD, I didn't want to keep trying to
fully restart the system until the car got back to her dealer and a
more controlled environment. I asked the AAA guys if they carried a
scantool of any sort in their trucks -- answer: no. They're there
to hook and haul, not get into any diagnosis, but maybe some year
they'll start being issued cheap scantools for cases where they might
be able to do something simple and get someone's car started again.
Not yet, though. This was interesting, though: they fetched the big
screw-in tow eye out of the back and installed it and used that to
winch her car aboard, and then powered it down okay.
.
Meanwhile we talked and I gave her a flyer and told her about
the online resources and forums and such. Maybe she'll show up
here and tell her own story eventually, but in the meantime seemed
happy to have me be her proxy. I told her to make sure to get
all the current and stored codes from the Toyota diag guy and to
email me the results, offered the wild-nice person theory that the problem
was somewhere in the fuel system, and then she jumped into the
AAA truck and we all got ourselves out of there.
.
It was interesting to note that said dealer, Jaffarian in
Haverhill MA, actually suggested that she try to drive the car
in, something over 30 miles with almost nothing left in the
HV battery. That's how much their service writers apparently
know about Priuses, so there's one piece of info for the
archives. We'll hopefully find out how competent they are
to actually find the problem and fix it. '05, 35K or so,
theoretically just barely still in base warranty, so we're
hoping that whatever it is works out to a free fix.
.
_H*

 

Well, that's likely to become more and more true as the Prius
goes more "mainstream", as it seems to be doing as fast as it
can be shipped. They're everywhere now. And driven by the same
people who were tailgating you in their Infiniti-qx-whatever-
makes-you-look-fat SUVs last month. The cozy little cult is
rapidly becoming diluted, but that doesn't prevent some of us
from keeping the mystique alive.
.
On the other hand, sometimes I get thumbs-ups from SUV drivers
or passengers, go figure.
.
I did find out a little more from the owner. Evidently the
problem was the air filter not installed right and some sort
of crud had gotten down where it made a difference to a
sensor, possibly plugging up the MAF. Damn, and I thought
I should have popped the air box lid and had a look, but I
didn't. It was a simple and cheap/free fix and she's back
on the road now -- insert happy-ending music here. Hopefully
the engine didn't ingest anything nasty in the meantime.
.
_H*

 

Hard to say whether a MAF blockage would have been visible or
not, it probably depends on the exact type of detritus that got
down in there. The sensor is VERY touchy about airflow, though.
Today I let the engine idle [y'all remember how to do that, right?
See the Georgia inspection threads] and with the air box cover
open, simply stuck my finger down over the MAF opening that
leads into the hot wires:
.

.
Even before my finger got there and was just waving near the
sensor, the engine note started to change. Once I mostly blocked
the opening, the engine promptly sputtered and died. So the
MAF is very key to having it run right, and very sensitive to
any sort of disturbance. The MAF assembly only samples some
fixed fraction of the total air flow, so variations in what it
sees will likely create a more profoundly distorted picture of
how much fuel to inject.
.
So if you play in that side of the air box, keep it very very
clean! I would have really liked to see what the Toyota guys
found that afternoon.
.
Interestingly, when the engine died in Neutral no warnings
came up. I guess the car doesn't care what happens to it in
that state, it only cares when the hybrid ECU has control of
things and the engine misbehaves.
.
_H*

 

It's kinda too bad that car doors are so flexible, huh? If
they were designed with multipoint latching systems, tools like
that would be useless. Nonetheless, the locksmith industry
is still awash in kits to maneuver around the innards of doors
[and often rip wiring harnesses in the process]. Nice that one
of the good guys is running around with good intent, but be
ready to do a lot of explaining if you're in a traffic stop.
.
Pinan -- I generally read my forums in a text-based browser in
a shell window, where 80 columns is still the rule. If you saw
most posts' data content in the raw, it would be one nearly-
unreadable huge line out to the end. Narrow columns are more
readable, as any newspaper layup jockey knows.
.
And before you ask, the extra periods are to maintain interline
whitespace which otherwise doesn't seem to work for me...
.
_H*