why no oil pressure, water temp gauges

What would you do when you're driving along at 35 mph, the ICE shuts off and your oil pressure drops to zero?

 

That's a valid answer for when you are in slow speed traffic but what about when you are cruisin' down the highway at 55+ and the oil pressure drops to 0? And, at any speed, what about if a hose pops and you lose all your coolant and start to overheat? I too found it odd that there were no gauges/idiot lights of any kind. This is the first car I've ever had that's not had gauges.

 

Nobody really knows why Toyota chose to install so few good
diagnostics in the Prius, other than the theory that they wanted
to make it *simple* for the then-new community of owners who
were still a little leery of "hybrid technology". Since then,
some of us who have installed instrumentation find it absolutely
essential, and others still don't care one way or the other.
[But most of the non-owners I talk to are still amazed that it
doesn't come with a tach.] Lack of instrumentation and lack
of a good understanding on how the system works is probably why
the original 60/52 EPA numbers were so low when the car is
capable of much better than that, properly driven. And now of
course the numbers are even lower than that.
.
They could have done a whole lot for the gauge-addicts with just
a little more programming for the screen display, and the folks
who didn't care about that stuff could simply choose to not
bring up the appropriate menus. But they didn't, which some of
us took as a challenge.
.
_H*

 

Not being technically proficient, I'm wondering whether a tach would function properly, if at all, if the battery were doing the propulsion. Extending that thought, would it be accurate if the battery were helping the ICE.

 

A monster instrumentation selection for the MFD would be awesome.

A tach works just fine: when the engine isn't turning it reads zero :_> Would you want the tach to indicate engine RPMs when the engine is spinning but not delivering any power?

 

Actually, if you have a ScanGauge, the tach does report the engine RPM when the engine is spinning because you are over the 41 mph transition speed. I also monitor fuel flow (gal/hr) and you often see ~960 rpm with 0 gal/hr.

I use the ScanGauge to add: tach, engine coolant temp, ignition advance, fuel flow.

 

All those gauges are cool, but basically not essential at all in car like Prius, where 99% of things are automatically controlled.
Regarding low oil pressure, high engine temperature and similar things, appropriate warning lights will turn on, when things go bad anyway, so no need to worry about it.

 

But its actually a little worse than no gauges, because what Toyota supplies is misleading. The power indicator gauge can show that only the EV is applying power, but that does not mean then ICE is not running. A tach would have at least made the truth about that clear. Its why I want a ScanGauge too, but I'd like one that was built into the Toyota display screen. The have add-ons that display my iPod on the tuch screen, how about one for a ScanGauge type device!

 

Oh right, forgot to add that there's no oil pressure sensor that
actually gives a pressure figure, just a switch that grounds
when it's too low.
.
I'd say the most important gauges I use while driving are the
tach and the battery-current meter. The tach does go to 0 when
the engine is stopped or is being spun in fuel-cut mode, because
the tach comes off the ignition system. In the case of the Prius
the tach can also indicate engine load to a degree, but you have to
know where the sweet-spot ranges are. For that I've got a vacuum
gauge and more recently have taken to watching fuel-injector time
on the SG.
.
So you see that much of the instrumentation you want can be
had in a variety of ways, you just have to DIY...
.
_H*

 

As far as it concerns to me, I don't care about gauges on my prius, if you have a problem with the oil, there is a light and a code of error indicating which kind of error did you have, and like this the other problems will work. Tach? this car has a very accurate way to keep ICE running on their most efficient range at anytime, and there is nothing you right foot could do to raise rpms over the red line, moreover, there is no way you could get and injection cut-off...

I do really think, there is no need to have those gauges... But if you are a gauge-sick-hybrid-driver, get a scangauge.

I would also like to mention that most of the cars do not have oil pressure gauge, or oil temp gauge, unless high performance ones...

 

^^^^
I can relate...."out of sight, out of mind"...
LOL

 

Search PriusChat for CAN view. you might be pleasantly surprised

As far as an oil gauge, I am in the small vocal minority that thinks an oil pressure -> zero event (with the engine running, and as rare as it is in Prius) ought to be accompanied by a warning at least as intrusive as the low fuel boing. All the hardware is present, only lacking a bit of Toyota programming.

At least 2 people, to my knowledge did not notice the oil warning light, and I don't really blame them.

 

You will in time come to realise the Prius is a Toyota and it is most unlikely anything will go wrong as long as you maintain it properly and most unlikely if you don't too!
Relax and drive it.

 

It really would have been great if Toyota added a screed to the MFD to take the place of the guages - When the ICE is operating - Oil Pressure, Coolant Temp, Tach, and instant and average MPG - All the info is there, they just need to display it.

 

I was demonstrating my Scangage functions to a SUV-driving friend. I showed him the temp, volts, current mpgs, etc. I said, I can't show you the tach because it is zero. We were going 35-40 on a slight, but longish downhill, and the engine had shut off. He was amazed.

 

I like passing people with the fuel flow rate at Zero.

 

Although having left out irrelevant info like oil pressure and water temp....
Lets instead admire what Toyota did give us indications of......
Energy flow indications that allow the user to take full advantage of the hybrid drive system, and more significantly, the ability to manipulate it.
That is a heck of alot more useful that any by-gone guages.

Oil pressure is irrelevant in a low performance engine that shuts down regularly, a simple idiot light will cover you the rest of the time. Would you really want to look at and interpret the relevance of a guage that would fluctuate to zero in normal operation?

Again, water temp variations would are irrelevant in a low perf. car like this. And in the normal course of operation would fluctuate too greatly for the average person to be comfortable with. An idiot light will do.

A tach may have mild usability for someone who is trying to exploit every facit of hybrid operation, but considering the driver has no real connection to the throttle, nor control of the constantly-variable transmission ratio, what real usefulness would a tachometer be to the ordinary driver? Think about it. Most of the time you are not really controlling what it would indicate, and the guys with tachometers are really just reacting to the engine speed chosen by the control prorgramming.
Besides, the average person doesn't understand the relationship of engine speed and gear ratio anyway.

As for the hypermilers and exploiters........the tools are out there.

The prius is all about change and progress, irrelevant info is really-- just that. I am completely convinced most folks still don't appreciate what this car is all about, nor how to take advantage of it.

And if you disagree, just look to modern aircraft, where all traditional dial and guage indications have pretty much been eliminated. Instead, they rely on automated background monitoring (idiot lights) and indications to the operator only when things are outside limits. If it's accepable in a airplane, I think it's ok in car.

Why be distracted from the task at hand-- getting good mileage-- by irrelevant info?

 

9G, you're actually missing a lot of stuff -- if one wants to not
be distracted from the "getting good mileage" task at hand then
there is some instrumentation that is ABSOLUTELY ESSENTIAL to have.
A tach being part of it.
.
Since as you correctly say the driver is mostly divorced from the
throttle opening, we can consider the engine to pretty much be a
constant-torque device. Take note of what Toyota shows about
the "operation region" -- never getting into a high-RPM, low-torque,
inefficient regime. Thus, RPM is directly related to how much
*power* one gets from the system and being able to monitor that
over time and terrain is important to the high-MPG driver.
.
Engine temp is also important to keep an eye on because it tells
us when we can or can't get into various operation stages.
.
Maybe Toyota wanted to make it easy, but maybe if they'd added
a real gauge set and offered the information on how to make the
best use of it, more people would be into the fun of driving this
way. Removing the choice entirely was a big mistake on their part,
and fortunately we've learned how to compensate.
.
_H*