Weak MG2 ? how to measure output?

I don't know about techstream but I do know that the hybrid assistant app will show MG1 and MG2 temp and that a scanguage will show MG1 and MG2 temp, RPM and Torque. I would think if the torque figure of MG2 in the 2 cars is very different under similar conditions, that might indicate a problem.

How about telling us more about your vehicles. Did you replace the HV battery in the 2012? If so, with what? Does the 2011 have the original battery? Have you assessed the health of the batteries of both cars? How about the bad engine in the 2012? What did you do about that? Have you replaced the transaxle fluid in the 2012? If so, what did that look like? Aside from accelleration does the 2012 run well?

 

I would concentrate on other items. First is the mpg ok and you have no codes? If so you are likely good. Second, any wheel bearing issues causing drag? Likely at 350k. Third is your hv battery weak and often at the low end of its state of charge? The hv battery is essential for power as the engine alone is weak. Fourth, is the 12v battery very weak sucking up excessive charge? This is essentially a power drag also. Fifth, Are you using the AC more than in your other car. The ac sucks hv power as well. I assume you replaced the bad engine. Loss of power from a bad engine is car repair 101.

 

Maybe you should drag race your wife and settle this quickly. The engine does send power to the wheels in parallel (at the same time) with mg2. Mg1 can be charging the hv battery or can supply additional power to Mg2. Mg1 is primarily a generator in gen2 and gen3s except when it is used to crank the engine.

I once ran out of gas in a gen2 at highway speeds. The hybrid system drove another mile and a half using electric only to a gas station. After gassing up, the hv battery was depleted further than any time before or since. It did crank the engine. Driving away the car was getting no help from the hv battery as the engine was heavily charging the battery while moving the car. It was pitifully slow to reach highway speeds. So a bad hv battery will absolutely impact acceleration.

To understand the cvt you can go to Weber State University and have a professor show you around. Or you can just watch his videos where he tears hybrid parts apart and puts them back together again. Including almost all variations of Prius inverters and transaxles.

 

Those X-Gauge settings are available on the Scangauge company web page

 

The power always flows partly through the gear train and partly through (MG1 to inverter to MG2). The proportions of power taking the two paths will vary over the operating range. The gear train imposes a never-changing torque ratio of 72% mechanical, 28% electrical, but power depends on both torque and rpm.

The Weber videos will explain how that happens, but a simple Prius nomograph is all you need to see what happens.

On the nomograph, you can even locate some sweet spots (a whole sweet curve, in fact) where virtually all the power is being carried mechanically, and the electrical path is hardly used. You can find those by pinning a ruler to zero MG1 rpm and finding any combination of engine rpm and car speed that it can pass through.

In high speed, low engine rpm 'overdrive' cruising, there's even a so-nicknamed "heretical mode" where MG1 back-rotates and electrical power flows in a direction you don't expect. It's a little befuddling to think about but the math works out.

 

Also keep in mind there was a inviter software update for the gen3 due to failing/overheating inviter unit Toyota made a update that actually throttled back the amount of current flowing through the inverter under normal driving.

I have see many people post about a loss of mpg, and some even saying the gas engine seems to work harder, which would make sense if you’re throttling back the amount of electricity to the electric motors during acceleration/braking.

 

There isn't likely anybody outside Toyota who knows what that software update actually did. "Throttled back the amount of current flowing through the inverter under normal driving" is one guess.

We know the problem they needed to solve, which was that solder beneath an IGBT would crystallize in a bad way if it cooled too quickly after being heated in strong acceleration or braking.

I think if I had been asked to find a software solution for that, I would have tackled it from the too-quick cooling angle rather than by capping the power. Maybe it's possible I'm so much smarter than all Toyota engineers that I thought of that and they didn't?? Or maybe they studied that approach in more detail than I have and found a reason it couldn't work. But they haven't published what they did change in the software, and while anybody can guess about it, that is what we're doing.

 

They likely told the software guys to implement an engineer's axx guess (WAG) in an attempt to reduce the number of cars that needed hardware replaced. With similar logic they initially excluded repairs on the v wagons. Until a class action suit began. Then Toyota quickly added the v to the repair list and settled the class action suit with said fix. The software hail mary did not work on my v's inverter which suddenly stranded me in another city a year later.

 

Take Techstream recordings of both your car and your wife's car from the engine and hybrid (hv battery)ecu's during similar acceleration- then compare them. Things to look for and compare is total volts and amps from the hv battery, MAF readings from the engine, etc.

Posted via the PriusChat mobile app.

 

This might be just my bug-bear, but just to rule it out:

raise the rear of the “sluggish” car, and check that the wheels spin semi-freely. It’s very easy, DIY’ing the rear brakes, to miss the requirement to have the caliper piston rotated (and solidly seated) with the spoke pattern on it's face oriented like an “X”. This is paramount to avoid brake drag. And grossly uneven pad wear. And rotor scoring. All sorts of bad stuff.

 

If he only rebuilt the front brakes are you suggesting the rear pad to caliper alignment can be off from wear alone? I suppose someone else could have botched it earlier. Seems like the hubs could be worn at 350k miles just as easily.

 

As soon as you’ve got two of anything, this can happen. Not saying it’s in your head, just maddening.

first time I had a motorcycle with two pipes, yup, one was more sooty; drove me nuts.