ICE engine stays on.....

When this happens, what does the traction battery SOC gauge look like on the MFD?

 

This is totally normal behavior for all gen2 Prius. This is the transition from hybrid stage 3 to stage 4.

 

If the OP's confused by mention of stages, Google for

Code:

site:priuschat.com 5 stages pdf

.

 

At my work we use the expression IFC, standing in for Issued For Construction. Often times people say "issued for IFC". See the problem?

So Internal Combustion Engine Engine?

My 2 cents: engine used to work just fine.

I'm an anti-acronym troll, know it at least.

 

Yeah. The short version of the story is this. Once the engine is up to temperature it no longer cuts out when you glide (lift the foot off the gas) unless you start the glide from greater than 35 MPH. If you start the glide from under 35 MPH then the engine continues to idle until you come to a complete stop, at which point the computer does some kind of sensor calibration which normally takes 5 to 10 seconds, and then it cuts out the engine and puts you into so called "hybrid stage 4". Once in stage 4 it will cut out the engine during glides from any speed.

Sorry. I did intent to post a link to the "stages of hybrid operation" in my first reply but things got a bit busy here and I forgot. Yeah it's an interesting read isn't it, quirkier than you would imagine.

BTW. Here's a direct link for anyone coming late to this thread. http://www.techno-fandom.org/~hobbit/cars/five-stages.txt

Edit. Corrected the 42 MPH, should have been 35 MPH.

 

JC, just as stated, the Prius in hung up in Stage 3, and just hasn't warmed up yet to stage 4. It has to reach the threshold and then have the ICE come to a complete stop for at least ten seconds to make the transition. It will stay in Stage 4 as long as the temp of the coolant doesn't fall below the threshold or the Prius is powered down. If you power down, then the cycle repeats itself but is faster if the Prius is at normal operating temp or close to it.

Try grill blocking that one if the temps will allow it. I see the same thing on ours when the temps are cool. I don't grill block, but should.

I believe all Prius owners should know about the five stages of Prius operation, that is why it is linked in my signature below. It really makes sense and helps those who are serious about hypermiling.

 

On Gen 2 Prius, there is NO indication of whether or not the ICE is running. The MFD won't tell you and the arrows are not an indication.

The only way to tell is is via tachometer, either old fashioned or something that will tell you via the OBD 2 connector e.g. Amazon.com: ScanGauge II Ultra Compact 3-in-1 Automotive Computer with Customizable Real-Time Fuel Economy Digital Gauges: Automotive. SG II will show you ICE RPM. ICE is off when ICE RPM is 0.

 

Which is nowhere near a reliable indicator.

If you get a Scangauge and watch engine RPMs, you will see that the arrows are NOT an indicator and you will be wrong most of the time about when the ICE is on/off when coasting (except when at or close to a standstill, when you can hear it).

 

One can also listen to the ICE if they don't have the radio blasting and the A/C blowing full speed. I wish I had a ScanGage. Maybe someday... LOL, posted as cwerdna did.

 

Even w/the knock or whatever, I seriously suspect you're wrong. Once you have a SG (or something else that will show you ICE RPMs) and watch engine RPMs, you'll realize how far off your predictions are.

I wish I had some time and had my SG mounted near the MFD. If I took a made a video showing you the two + the speedo and narrating my actions, you'd see what I'm talking about.

Sure, it's obvious when stopped or walking speeds but it's definitely not when coasting nor at very light throttle above say 15 mph. And, it's always running at 42+ mph.

 

Yeah that's right, the MFD graphic with the arrows only show the engine running if it's actually providing power to the wheels. When the engine is just idling without providing power it doesn't show it.

Another way of sometimes detecting the engine running in this so called "stage 3a" is by observing instantaneous fuel consumption. In the Australian model we have "liters per 100 km" (instead of MPG) for displayed fuel consumption, and it's quite sensitive at measuring very low consumption levels. In L/100km it can report fuel usage as low as 0.1 or 0.2 (l/100km), which corresponds to about 1000 to 2000 US MPG! So generally I can see if the engine is idling by just looking at the instantaneous fuel consumption and noticing the very small fuel usage.

Unfortunately with the MPG instantaneous display it's more likely to just peg at 99.9 MPG whether or not the engine is idling. From my measured fuel consumption data I've estimated the fuel usage for this "warm idle" to be about 0.75 L/hr (0.2 GPH US), so the displayed MPG should theoretically be about S/0.2 = 5S under this idle condition. That is, the displayed MPG should be about five times the speed (in MPH), so it will mostly just peg at 99.9, but you should be able to detect it sub about 20 MPH.

Not sure they look too bad without a more close up image, they seem fairly comparable to these: Spark Plug pictures after 120,631 miles | PriusChat

Remember that the fuzzy grey coating doesn't always just build up. I think it's more like an equilibrium condition between deposit breakdown/removal and build up. They'll probably look worse if the last thousand miles have been lots of short trips and cold engine, and better if it's been more longer trips and highway cruising.