From o2 sensor to engine replacement in 10 days?

Have you ever heard the nuclear term “trust but verify”? I would be there with a GoPro recording every move of the tech at this point. Don’t let these assbags touch your car without you being there recording what they do at this point.

 

Who said covertly? Bring a damm camera with you and make it known you have one. Have Thing 1 run the camera

 

I would not trust those guys to count the number of Klingons on Uranus at this point.

 

Basically the compression test tells you the pistons and valves are doing what they are supposed to do. That means it’s something else. Spark and gas are the other 2 components that make the engine run.
It used to be a lot easier when it was just a simple carburetor and ignition system. Now you have things like VVT that could mess things up also.

Go back to when the problem started. What was done to the car at that time?

You changed the Cat and the car ran OK but the check engine light went on? So you took it to the dealer and had them install an aftermarket fuel air mixture sensor? Then the problem started?

 

You can still have some serious engine problems while showing good compression scores. It would be really unusual, but technically not impossible.

Before I met a hybrid, the two most valuable scores I sought to diagnose old or sick cars were cylinder compression and oil pressure readings. Compression tells you about the top end, oil pressure for the bottom. Pass both? Your engine is fine- may need cleaning, sealing, tuning and refinement for drivability*, better power, emissions pass etc... but the engine is ok.

I haven't seen anything at all to question oil pressure in this case; so I can't counsel you to spend any time or money measuring it. It's probably fine.

*that front O2 sensor is the primary instrument used by the ECU for real-time tuning. Get that done.

 

Not that I want to bring up another place to check, bad fuel injectors (somewhat a known issue)? That'll cause the 4 cylinders to misfire.

 

O2 sensor voltage appears to be pegged low which says lean condition. Good O2 voltage should be oscillating around 4.5. It doesn't sound like the computer is getting imputed from your O2 sensor.

The dealer seems to be stuck on sludge. I say screw the sludge, fix the car.

 

If an O2 sensor was the only issue, that would show up immediately.
Most cars with O2 sensor problems will eventually force the ECM to run in open loop, ignoring the bad sensor data, which would force you to reset the ECM to clear the code, and acceleration would be sluggish, and idling would be unstable, knocking and sputtering on pedal depress. Not an engine killer, just annoying.
From the description of your problems, it is far more than a simple O2 sensor malady.
I am for more interested in the HV battery capacity and life of the assembly.
From the low charge rate, you are not getting enough voltage or current to the battery.
Might be cable issues..Check everything....twice.

 

The first dealer, raked you over the coals, and did nothing to actually solve your problem.
All things being equal, the simplest explanation, must be the problem.
This is why dealers are rarely considered, where repairs are concerned. They want the big money, and easy fixes.
Customer service is a full time job, but they dropped the ball on you, and then tried to cover up inept service with excuses...
We have not had our Prius long enough to become fluent in every facet of its operation, or maladies, and hopefully never.
I certainly hope you will be able to pinpoint the areas of concern, and eliminate them as well.
I wish you success in that endeavor!

I will be doing something similar, by locating a good service manual for the drivetrain/power control systems.
If I feel qualified to do the work, I will.
Electron flow is my life, that portion will be simple for me.
I do not get involved with heavier tasks as I once did...pulling engines, transmissions are now history for me.
The 'lure' of rebuilding those, has faded to dull glow.
There has to be a solution, and all of us might be dancing around the actual solution without recognizing it..

We are very familiar with deep, cold snow also...we closed up our house in N. Wisconsin, and moved to AZ. to get away from it. After 32 consecutive days at -28, we had enough. We winterized, drained the water from the on-demand well, shut off the power, and headed south.
All the best to you with your troubles, we hope they are soon eliminated!

 

Thank you for the response!

Even if I can only DL a copy, I can print out the most desired data, and store them in the car, for future use.

 

how long did it run for?