Still having issues

Bad PCV or EGR clogged? Throttle Body and MAF Sensor clean and functional? Spark plugs? Clogged fuel filter?

Is the HV Battery holding charge and cycling like normal? Hate to say it, but if it is straining under load and the above items are good, you may not be getting enough assist from MG1/MG2...

 

Sounds like the start of the end of the traction battery but what do I know

 

Ughh...I hate that answer. ( If The Computer says nothing is wrong, nothing is wrong) But it's the most common answer of the new age of automotives.

With a Prius it's harder to track down something like this.

I'm assuming you've already thought of all this, or have taken note of all this. But with a Prius there are more factors than a singular Otto cycle ICE vehicle.

Do your symptoms as described manifest all the time? Any connection with warm up stage or battery SOC?

The tricky thing is I'm getting 50+ mpg with my relatively brand new Prius, but on hard acceleration or if going up hill, it struggles and the engine rev's. When you say "Past it"? How much of this is tied to how your foot is pressing on the accelerator? Because again, My Prius MPG's drop and it strains to get momentum, but once reached I have the option of letting up on the accelerator and it "evens back out"...I don't define this as a problem with The Prius, I define it as how the vehicle works in relationship to momentum and physics.

How long have you owned this vehicle? I'm also assuming the symptoms as you describe represent what you perceive as a change in behavior?

If this behavior is consistent....then perhaps your best bet would be to try to get a technician to ride with you, and get the vehicle to demonstrate. A vibration coming from your engine would be hard to ignore or deny. Saying to a technician that it is Reving hard while you are accelerating or going up hill? That is more easily ignored or filed under "not a problem"-even if it really is a problem.

Good Luck.

 

I would consider getting some metering going, via Torque or Priidash. I would want to see the temperatures of the inverter, MG1 MG2, and how much current the traction battery was able to give and take. What is the actual voltage of the 12V battery while the car is running? How is the battery fan?

 

Here's a pretty good benchmark of the car's performance:

1---Your not throwing any codes so it can't be that bad. Localized to engine performance I bet.

2---TEST: Find a nice level and quiet 5 mile stretch of highway. Get up to 55 mph's and then reset the consumption meter mileage to zero by pressing the button on the screen. Set your Cruise Cntrl to 55. Don't touch the gas or brakes for about 4 miles. AC & radio & lights on the Mfd should read at least 53 mpg's after 4 miles.

Having said that I agree with the throttle body needing a very good manual cleaning. This TB like most modern cars gets very sooty. On a tiny TB it really affect's the engine performance. It's very easy to do search back my old posts as I have a detailed description how to do it. Its easy.

Your also due for:

Transmission fluid (every 30k)
And Inverter coolant change (every 30K)

You'll notice after you change the Inverter Coolant fluid it will have much more aggressive agitation in the I reservoir (better pumping action) and you will see better mpg's also as it keeps the Inverter cooler with fresh fluid.

Btw, it's best to tell your mechanic what you want done rather than leave it up to him. Now armed with this new info you are much more informed than he is.

 

Matt, what is the HV battery state of charge (red/blue/green battery bars) doing during this time? Also, make sure you've got the engine warmed up before doing the test.

Here's some other stuff to think about:

- At 76000 miles you definitely should replace the transmission fluid (ATF), if not already done.

- You don't need to replace the sparkplugs yet, but it's not a hard job so it wouldn't hurt to give it a try.

- Clean the throttle body and make sure the oil is NOT overfilled.

- Some users have reported restoring lost MPG after adding a bottle of injector cleaner in to the tank (and other's have said these products are mostly snake oil). One brand mentioned (and supposed to work) was "Redline", but honestly I haven't used it myself, so take that with a grain of salt.

 

When should the spark plugs be replaced? And how do you gauge if oil is overfilled?

 

Do you have a gen one or two, on the two the oil is full, 2/3rd's of the way up the dipstick, and change the plugs after 75,000 with oem or better.
The op is incorrect about the role of the 12v battery, it will use gas when weak but it won't take power from the ice, the egr valve is a likely culprit, abusing the working man is always a mistake

 

I think the schedule for spark plugs calls for replacement at about 120,000 miles, but a lot of people do them as bit earlier. I'm currently at 112,000 miles and still haven't done mine, but my fuel economy is still good. I'll probably do mine within the next 6 months.

The oil is overfilled if it's anywhere above the top dimple on the dipstick (measured on level ground). Some people have reported getting the throttle body contaminated with oil and significant problems as a result of having the oil not more than half inch over the top dimple. With the prius it seems a good idea to consider any overfill at all to be bad news.

 

No on the Gen II the oil is full when its up to the dimple. Just like they designed it.

 

Gotta wonder what a ScanGauge might tell you.

 

If you decide to get a Bluetooth adapter and use Torque (an Android phone app), PM me. I've got some custom formulas to measure the individual battery voltages. The goal is to log the voltage deviation from the average for each battery bank.

If one battery bank is consistently showing a higher deviation from the others, it is suspect and is likely to be the first to go out of spec and trip the check engine light. You should be able to tell how quickly a failing battery bank is dieing by how quickly the deviation voltage number grows.

In a perfect battery system, all deviations numbers would be the same. This indicates that all batteries are charging and discharging at the same rate and therefore have approximately the same capacity.

The trick is to do the math every time instead of relying on the stored average. They often don't update together and you end up with false readings.