I miss my gauges.....

Discussion in 'Gen 4 Prius Technical Discussion' started by Valiant V, Jun 9, 2021.

  1. Valiant V

    Valiant V Member

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    As a mechanic and a driver that actually likes to monitor engine gauges - I feel a little naked with so few indicators of how the engine, transmission, cooling system, etc are doing on the Prius.

    "Idiot lights" have their place as most drivers don't watch oil pressure or coolant temperature anyway - so lighting up when there's a problem is more useful to them.

    However, knowing what a normal oil pressure or coolant temperature is can allow an operator to see problems before they become serious. Seeing needles on a gauge right where they belong can be a reassuring thing.

    Having used a bluetooth OBDII dongle(?) and a smartphone app (Torque Pro) I know there are a bunch of sensors and values you can monitor on an ICE car - stuff i never knew was out there. I see from the Carista App, that there's "No Live Data" available on their app for the Prius. I'm guessing that means that you can't monitor that kind of data on a Prius - at least not with Carista.

    Have other owners found a fix for their gauge habit?
     
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  2. fotomoto

    fotomoto Senior Member

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    I use older tech in the form of a scangauge II and an even older ultra-gauge. The SG can only show four gauges at a time while the UG can show a few more but both are capable of displaying just about anything available thru the OBD port. The SC is better for a HEV specific readings and developing custom PID’s.

    FWIW
     
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  3. ChapmanF

    ChapmanF Senior Member

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    I use a ScanGauge II, small enough to just sit on top of the steering column, and will display any four PIDs that you choose to have displayed. Many will use a phone app to do the same thing.

    For some, you have to look around and find out if anyone has reverse-engineered the PID information that you have to program into the ScanGauge or the phone app. I know there were pretty comprehensive lists that got figured out for gens 1, 2, and 3. I just haven't looked to see how much has been accomplished for Gen 4 yet.

    In some things, you're limited by what sensors the car has. I think it might only have a low-oil-pressure switch, not a pressure transducer, for example, so you won't have much you can watch there.
     
  4. Valiant V

    Valiant V Member

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    As this is one of the most "computerized" cars I've ever owned, I'd be very surprised that it didn't have vastly MORE sensors than the 21-year-old (and older) dinosaurs that I'm able to pull some pretty detailed information from.
     
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  5. alanclarkeau

    alanclarkeau Senior Member

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    I think there are many, many more in use that are hidden from us. Things like the YawRate sensor, the steering sensor, the many temperature sensors, Atmospheric Pressure sensors - are all used by various functions on the car - but of no interest to almost nobody.

    I remember when Gen 4 first released, there was someone here ADAMANT that it should have a tachometer. I've not seen it - but I read about one (might have been on another forum) where someone temporarily installed one - and the tacho did such "weird" movements - the person said after a while - it was no point.
     
  6. Valiant V

    Valiant V Member

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    Well, of course the tech would have little value when the vehicle is in EV mode - or the oil pressure for that matter.

    For that matter, tachometers are really of very little use in any car with an automatic transmission since the tranny does all the "deciding" when to shift for you. Probably why tachs on cars with automatic transmissions are not super common now. Sure, you can see "At a certain speed, the engine is turn at XYZ RPM" - but it's really academic.

    Still, knowing what a normal coolant temperature is under given conditions can tip an (attentive) driver off to a problem that is brewing but isn't to the "OMG - Stop the car now!" level. Maybe it's time to pot the hood and make sure the radiator isn't blocked by a bird's next or that a cooling fan is obstructed. Likewise, oil pressure can tell you when your engine is getting tired - or hot - or that that you have some other issue with your lubrication system before you get the idiot light which only tells you that serious engine damage is imminent.

    I just like to know what's going on under my hood and not abdicate all of that to a computer. Sure, there will be plenty of things you can't even influence, but without knowing what's normal, you can't even spot what's abnormal.

    Who knows, yaw rate may be pretty interesting once you think about it.
     
  7. Fester

    Fester Active Member

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    I use two ScanGauges stacked together on the steering column. the lower one typically is set to read Coolant Temp,12v battery current and voltage, and main battery charge/discharge current. The top one usually is set to display all the tire pressures. Having spent quite a few years in the engineering field, I like to be able to see whats going on with the systems and maybe stay on top of a problem before it gets to the point a "idiot light" comes on.
     
  8. Valiant V

    Valiant V Member

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    Likewise.

    As a pilot - monitoring the health of the engine - especially when you only have one and there's no "Motor Club" - is a habit that one acquires.
     
  9. bisco

    bisco cookie crumbler

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    some people monitor battery temps, cooling fan speed and etc.

    toyota has a proprietary black box for the stuff they don't want you to see.
     
  10. ChapmanF

    ChapmanF Senior Member

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    Still, they aren't spending money on sensors they haven't got a use for as inputs to the algorithms they're using to control the car. Oil pressure switch vs. pressure transducer is a case in point.
     
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  11. Valiant V

    Valiant V Member

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    Sure, with a vehicle that uses different technologies, you'd want to monitor different things.
     
  12. Valiant V

    Valiant V Member

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    Oil pressure may not be a good example in this case.

    Coolant temperature more likely is.

    For example, my old Ranger has two temperature sensors - one for the the gauge the driver, and one for the ECU.

    Even my older Pontiac had a wealth of information available when you plugged in a OBDII linked to Torque Pro.

    The number and type of sensors is something an owner can't easily change - monitoring the ones that are there should be somewhat easier.
     
  13. AzusaPrius

    AzusaPrius Active Member

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    Think of the Carista app as a firewall, only giving you access to what they want.

    The OBD Carista reader can be used with Torque app just fine.
     
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  14. alanclarkeau

    alanclarkeau Senior Member

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    HeeHee. I can just picture my younger days, hot-footing up a mountain pass, testing the adhesion limits with different tyre pressures. A Yaw Rate Sensor would have just been the bees knees:eek:.
     
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  15. fotomoto

    fotomoto Senior Member

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    Heck you can get one of those (and more) by adding even a cheap aftermarket radio (not as cheap as a SC) nowadays.

    upload_2021-6-11_8-15-22.jpeg

    upload_2021-6-11_8-17-4.jpeg
     
  16. Valiant V

    Valiant V Member

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    I would have thought the tire pressure display would have been a no-brainer - especially for a car that depends on running higher pressure to achieve the best mileage.....
     
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  17. fuzzy1

    fuzzy1 Senior Member

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    My old Subaru didn't need a separate sensor for the gauge for the driver. Instead, it displayed a seriously 'massaged' version of the ECU reading. Everything from at least 145F to 210F (maybe even wider, I don't fully explore) was collapsed to a single point on the dashboard temperature display. In normal operation, despite fluctuating coolant temperature, the needle wouldn't budge a bit, thanks to built-in "customer expectation management".
     
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  18. Valiant V

    Valiant V Member

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    It's true - most gauges on IPs are about useless. Some coolant temperature gauges only have a number at the top and one at the bottom of the scale, and you have to interpolate to get an estimate of what the actual temperature might be.

    That said, I know exactly where the "normal" operating temperature of my 2000 Ranger and 1993 Chevy van are from observing the position of the needles on the scale. So if the engine "isn't warmed up" yet, or is hinting that it's running hot - you can see that.

    Likewise the oil pressure gauge on the Chevy van was very diagnostic of what the engine is up to. Gets pretty high at cold start-up with 10w-40 oil in the winter, comes down as it warms up, and flutters around the lower end idling hot.

    On the other hand, the oil pressure "gauge" on the Ranger IS a joke. It's a gauge, but hooked to a pressure switch. So upon startup, it instantly jumps to a certain spot and never moves until you shut down the engine. So as long as the engine has 5PSI (guessing) the gauge shows "normal".

    Both the Ford and the Chevy DO have dedicated senders for the IP temperature gauge. I don't know if the older Chevy had another one for the ECU - but the Ford DOES.
     
  19. mr_guy_mann

    mr_guy_mann Active Member

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    Gauges are only useful for people that: 1) actually look at them, and 2) understand what they see.

    Temperature and oil pressure gauges used to be (somewhat) linear and accurate on some cars. And the drivers that had them would often come in saying "this gauge reads higher here, and then lower there!" I would have to explain that engine temperature normally goes up after a 5 minute hot soak or that oil pressure is lower at idle after extended highway driving in summer.

    Apparently the OEM's got tired of explaining things over and over to buyers that had no clue (and didn't want to have one) about how their car worked. The OEM's began "dumbing down" the gauges and going to idiot lights. Temperature guages were made to read - "none"(cold), "some" (ie normal operating range), and "lots" (overheat). So it's easy to see that going to a blue light/ no light/ red light.

    And it's hard to beat Ford's oil pressure guage that was connected to an on/off pressure switch. Under 5-7 psi would show 0 on the dash but anything over that would show a fixed value.

    Throw in the "weird" operating conditions of a hybrod ICE and there's no way that they are going to put (useful) gauges on it.

    Posted via the PriusChat mobile app.
     
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  20. Georgina Rudkus

    Georgina Rudkus Senior Member

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    It wouldn't be too hard to install a temperature gauge on the transmission and an oil pressure gauge on the engine.

    The transmission drain plug removed and a temperature sensor could be adapter to the M18x1.5 threads into which the drain plug is fitted.

    The same kind of adapter could be threaded to the removable M18x1.5 plugs on the oil filter adapter.
     
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