Love my Honda Clarity…and we also own a Prius Prime.  The Prius has lots more tech than the Honda, especially when it comes to monitoring the operation of the ICE (Internal Combustion Engine).  One of the simple upgrades is to install an engine hour meter so you can really keep track of how much the ICE is running.  This is most important for maintenance reasons.  And, if you’re concerned about the environment and don’t want to “over oil change” it is also a way to make sure you don’t throw out completely good oil.

Following the advice of KentuckyKen on the InsideEVSForum I purchased a low cost hour meter on eBay.  Shipped from the US, mine cost $6.98.  I purchased another from Hong Kong for $4.47.  I figured I’d do one for the Clarity and then try one for the Prime.

While there was a part of me who wanted to get a mechanical hour meter, I determined that not having to find a 12V wire that was energized when the ICE was on was a benefit of using one of these self-powered meters.  There is no power required as the meter has its own internal battery.  When it runs out, I’ll just buy another.

Here’s how it came.  Now to connect it to my snowmobile…oh, I live in Texas…I mean my motorcycle.

The package contents, unpacked.

The installation instructions.

For a mounting location, I like the plastic cover over the wires.  I think I can use the short screws through the meter to attach to the plastic cover without damaging anything.

The meter is just the right size to fit there.

See how it will look when installed?

Let’s remove the cover to expose the spark plug coils.  The cover just snaps in place with rubber grommets, so just pull upward to remove.  Here are a couple of pics to show you what the part looks like.

Now we have the coils exposed.

The easiest way to do this is to remove the coil.  Start by pressing the tab on the connector near my thumb end and gently pull on the sides to disconnect.

The coil is held in place with one 10mm bolt.  Simply remove it and pull up to remove the spark plug coil.  For all you old-timers, remember when there was one coil with spark plug wires running all over the place?  Now the low voltage wires are run to the individual coils and it makes for a much neater installation.  This EE loves me some electronics!

Here’s the fully removed coil.  So simple and elegant.

While you have the coil removed you can wrap the wire around it.  Try and keep it up off the seal.  What will happen is when you reinstall the coil you’ll find the wire is snugly compressed and, at least on my installation, it doesn’t appear to be going anywhere!  Be sure and leave enough to connect to the meter.

This is a little hard to see, but the wire just slips into the slot in the back of the meter and is held in place by compression.  Use a small screwdriver to shove it in place.

So here it is installed and I’m testing it.  Already have 0.1 hours (6 minutes) on the meter.  Had to run it around the neighborhood in Sport HV mode.

And here we are with the screws installed.  I’ll remove this in a bit and make sure the tips of the screws are not causing any issues.

Video:

Now let’s get out the label maker and put a label on it so those folks peeking under the hood will (hopefully) understand what it is.

After running around for a bit, punching it in Sport HV mode to get some hours on the ICE.

I love my Clarity.  But, I don’t feel comfortable knowing where the long front end is when I park the car.  So I embarked on adding some ultrasonic sensors to the front.  I suppose I could’ve added a camera, but I was looking for something a little less obvious in the cab.

This is not for the faint of heart.  It requires drilling holes in the bumper of your new car.  I was, however, able to do this without removing the bumper.

I ordered the Rostra FrontZone 250-1920-FZ from SavingLots.com.  $93 + 12.50 shipping:  $105.50.  I found the kit to be very complete and professional.

Something to note.  The Rostra system has a CAN interface that is supposed to detect when the vehicle is moving a certain speed (off at 10 mph and on at 6 mph) and disable/enable the system.  This only works on 11-bit CAN systems and my experience with attaching it to the OBDII port with the included connector has been disappointing.  I keep getting the E0 message.  At this point I’m not sure whether there is an incompatibility issue or not, as I understand most CAN-B (29-bit) systems can understand CAN-A (11-bit systems).  I have sent a question in to Rostra, but as of 6/9/2019, they have not responded.  I’m going to be rather torqued if they never respond!

“If the ECU is disconnected or getting incorrect information from the CAN-BUS interface, “E0” will be displayed and the system will sound 5 beeps consecutively.”

I first had to determine where to mount the sensors.  I decided I wanted two of them to be low (closer to the curb) and the others to be in the approximate locations recommended by the installation template.

For the sensors in the bumper, I measured from the car centerline…approximately 795mm.  After measuring, I pushed on the bumper and looked behind it with a light to make sure I could see where I was pressing and there was adequate clearance.  I marked the distance with a grease pencil and then measured to center the vertical distance.  I used a level to plumb the measuring lines.  I double and triple checked my clearance.

For the low sensors, I installed them in the black plastic trim area.  Perhaps I should’ve gone lower, but this seemed to be a good compromise of keeping them at the recommended 12” minimum height.  I drilled these first and actually used the drill for a metal bumper, so I had to install the rubber grommet retainers.  No big deal…they fit nice and snug.  And no painting required!

I painted the two mounted in the bumper with some white enamel paint.  I looked at trying to exactly match the pearl, but the would’ve required spending $75-100 on a multi-step paint.  Close enough.  Finish them off with some rubbing compound and a little wax.

The wiring part came next…and this was not easy.  I drove up on some ramps and removed one of the under covers.  This required removing 14 or 20 clips and a couple of bolts.  Not hard, just watch out for dirt dropping in your face!  I didn’t get any good pictures of this part of the process, but here are the clips and the cover, so you can get the idea.  This allows access for the wiring.

To get the wiring to my holes in the bumper, I used a piece of stiff wire to which I taped the ends of the wiring harness and fed them from below to the hole in the bumper.  I used a pickup tool or pliers to grab the end of the harness I was feeding from below.

Now for the part that took me hours to figure out.  I needed to get the harness through the firewall, but I really didn’t want to be drilling holes, mainly because there’s just not much room to work.  After messing around for hours, I finally determined I could shove the harness through the side of one of the big wiring harness grommets.  Here are some pictures of this from the firewall side.  Of course, you have to have access on the cabin side as well.

This first one shows how I was able to lift up the side of the grommet and, using a long screwdriver, pull it away from the edge enough to shove the harness through.  You can see the grommet that was on the wiring harness that would be intended to fit in a drilled hole.

Here’s another shot showing more of the large factory wiring harness grommet.  The red wire is my trailer hitch power wire I ran when installing my trailer hitch wiring.

And here’s another shot.  There is a factory plastic clamp (unused) that I commandeered as part of the wiring harness retention system.  I subsequently secured the harness with wire ties.

To access the cabin side of things, you can remove some trim pieces to gain access.  There are basically four trim pieces I removed.

The driver’s dashboard lower cover.  It just pulls away when you pull in the clip areas.  No screws to remove.

Here are some pics of the back side of the dashboard lower cover so you can see the white clips and the connector locations.

The driver’s kick panel.  Pull it toward the passenger side to remove the clips.

The door sill trim piece comes off by pulling straight up.  Not sure if you really need to remove this or not.

The side cover for running the wire for the display.

Location of the clips on this cover.

With the cover removed you can easily run the display wire to my location of choice.

This is my display location, before it was stuck down with the included double-sided tape.

Here’s the final location.  Very unobtrusive and out of the way.

To be able to turn the whole thing off, should it decide to beep randomly (and to account for taking it through car washes), I installed the included switch in the right hand blank.  The blank pulls out and I did some drilling and modification of it to allow the switch to snap in.  Again, you can’t even see this after installation.

 

After it was all hooked up I did some testing.  I used a small Pelican case as my target.  Here are the display readouts along with the associated tape measure “read out.”

The sensor is actually a 2-3 inches back.

This is the measurement to the bumper.  Anything less than 12 inches causes the display to beep constantly…as in “don’t go any further!”

Pretty accurate.  About 22” inches from the driver’s side.

At about 30 inches from the passenger side.

Right in front.

Measured from the license plate…that sticks out about 3-4” from the sensor location.

Overall, I’m very satisfied with the accuracy.