2010 Prius: Engine quit, P3190, but starts after two weeks

Hello Prius Chat,

I have a 2010 Prius with 196,000 miles. It is a major oil-burner (1 qt every 800 miles), but that might not be the source of the current issues.

On Dec 31, the engine quit while I was exiting the interstate. I drove a few blocks on electric power and pulled over. If I turned the car off and back on again, the engine cranked for 5-8 seconds, but didn't run. I had it towed home.

When I scanned the engine with a friend's scanner, I had code P3190. The oil was half a quart below the fill line. I assumed it was an engine sensor, fuel or spark issue.

Two weeks later, I got around to pushing the car into my garage and working on it. The chassis battery was at 11.5v so I connected a battery charger. I bought a Carista and used it for the first time. I pressed the brake pedal, expecting the engine to crank but not start. Surprisingly, the engine started, warmed up, charged the HV and shut off.

The new engine codes are P3190 and P3191, but the car is running. I've only moved the car in and out of my garage to work on it since then, but it has started multiple times. The engine sounds tiny a bit louder for the first second after I start it, but I wonder it it has been doing this all along.

Earlier today, I inspected the mass air flow sensor and throttle body, which were clean.

 

Update:
Below the throttle body, oil has pooled in the intake manifold.
The Manifold Absolute Pressure Sensor is drenched in oil.

 

I cleaned the MAP sensor and reassemble the intake system.
The engine fired up and there were no check engine lights.
I drove around the block two dozen times and then decided to drive a bit further, which is when the "check hybrid system" message showed up and the engine would no longer run.
Towed the car home, but it ran when it was coming off the flatbed!
This is confusing!

 

The saga continues!
The car runs, then it doesn't, then it runs again!
I had a friend come over with an Autel MaxiSys. I'll copy the scan data once I'm finished with work for the day.

This evening, I'm going to check engine sensors and take a look at the fuel pump.

I'm not sure if I should send it to a dealership or to the independent local shop that specialized in Prius.

(I keep thinking I finally have a good excuse to buy a pickup truck as a backup vehicle.)

 

Latest Update:
I had my car towed to a Toyota dealership. They said that the HV battery is bad. I told the dealership that I'll pay them for their time, but I'll replace the HV battery on my own.
I called up a remanufactured battery supplier, intending to buy a remanufactured HV battery. I described the vehicle issues, but they are hesitant to sell me a battery, suggesting that the issue might be something else.

 

I'm still not convinced that the battery is bad.
I drove my car home from the dealership; approximately 4 miles.
Last night, I changed the spark plugs to get that off of the potential issue list.
Once finished, I started the car and allowed it to do its normal warmup and charge cycles.
The hv battery started at three bars and charged to one less than full. No check engine light on the dash.
I turned the heat up and opened the windows to get the engine to start more frequently.
The engine was running about 75% of the time over 25 minutes.
The engine cranked and started, but shut off about 20 seconds later and the hybrid warning appeared on the dash.

I've been thinking that the fuel pump might be the problem, so I removed the rear seat cushion.
I turned the car off, waited a minute and turned it back on again.
I did not hear the fuel pump make its normal startup cycle. I'm not sure if this cycle does not happen if the vehicle has only been sitting for a minute and is still warm.

The car has been sitting overnight, so I'm expecting it to run when I go outside.

Updates later today.

 

Thanks!
I'll give maintenance mode a try.

On Thursday, a friend came over with an Autel Maxisys.
The only codes found were P3190, P3191 and P0A0F.

I have a Carista OBD2 Adapter (their app has major issues).
I tried OBD Auto Doctor, which gave me the same codes as the Autel Maxisys.
Dr Prius is currently loaded, but I have not purchased it yet.

 

My 12v battery output is 11.x volts. I wonder if this is an issue. It's under warranty, so I should replace it.

I replaced the original 12v factory battery in November. It would would not start the car if the temp outside went below 0.

 

I've watched that video before, but seeing it again makes me angry at the Toyota dealership!

I have copies of the service notes that state codes P3190, P3191 and P0A0F followed by "replace hybrid battery pack".
The other notes were "replace spark plugs (completed last night), clean intake manifold (completed last week), egr valve update (completed two years ago)"

 

UPDATE!!!

I removed the rear seat cushion and started the car.
The fuel pump buzzes distinctly.
The car runs for 10 minutes, charging the battery and running the heat.
I turn the heater off and the engine shuts off. The fuel pump turns off too.
I turn the heater on and the engine attempts and fails to start, I can't hear the fuel pump.

How do I remove the rear floor service hole cover above the fuel tank?
I want to try the "tap the top of the fuel tank" trick.

 

The EGR passageways are clear of soot.

 

Thanks!
I thought the arrow indicated "push in this direction."
It probably means "this direction is front."