Prius won’t get over 30mpg after new engine installed

Do you have any codes?

 

is the inverter pump working?

 

It's probably that light on front.

 

Your gonna need a scan tool or you'll just be guessing. And a compression test of the engine would be a good idea also.

 

You would think there would be a CEL

 

Well you'd think? But even if it did, it still would not tell you what was wrong? The Prius can be a Drama Queen, with it's Dash Board, lights. It can have an issue store a code and continue to function. It will work around the issue (if it can) and continue to function, while not bothering you with it until it can't?

And when it can no longer work around the issue. Our Gen Two threw a fit, lit up everything on the Dash. At 45 mph the motor quit, ie the gas pedal did nothing?? But around 34 mph it kept going in silence, on Battery. The battery was going flat so I looked for a place to pull over and call for a tow truck back home.

At first when I shut down it would not start. But while waiting for the Tow Truck, it did start?? And the Hi Voltage battery went back to full. So screw the tow, it was 6 miles to home so, I'll try and make it? 60 mph without issue, for 5 miles but the Red Triangle was still there?

Now this is where it tick's me off. I tried to scan it but none of my scanner's read Toyota? So off to the dealer it goes the next day under it's own power. And we get a call from Toyota that it is the Down Stream O2 sensor.

I know it was the second one because we have the record's for the car and the up stream O2 and the Cat, had been replaced under warranty before we got the car. The part that "still," ticks me off is "two week's" of no car and $450 buck's for an 02 sensor??

I add Wide Band O2's to older upgraded turbo car's, that don't have them, no big deal. But without the right Diagnostic Tools, with today's car, you have no idea what is going on under the hood?

You really can't play "Whack A Mole," with today's car's. That get's expensive. But you could at least have it scanned and see what show's up???

 

I have Toyota Techstream and adapter..... pretty sure it was under $50 on ebay or amazon.....

 

O₂ sensor readings and codes are in the ECM and should be available to a standard OBD-II reader. There must be more to the story why those wouldn't have shown up in that case.

For the OP ... it would be handy to have Techstream, and to do some logging of engine data on your test drive, including the difficult hill ... especially if you'd be able to get access to a working Prius v and take it around the same course logging the same things ... rpm, MAF, fuel injection, ignition advance, cam advance, etc.

Here's an example from another recent thread.

 

Cool and from what I know that would be the one.

But maybe start a new thread to ask about using it? I know nothing except maybe needing an older Windows Laptop??

 

You very well my be correct? It was two year's ago and we just got the car. I lifted
the hood to see the "motor," and freaked out. Screw this the I saw inventor and orange wires? Fuel and oil that I understand. I closed the hood and walked away.

But without being under stress, I'll try the scan tool I already have and see what it show's if I can find it.

 

Compression being good is great, so it has to be something else?

 

nah, that can't be. aerodynamics are bogus marketing hype n stuff

 

If you think the downstream O2 sensor is creating a problem, just disconnect it where it plugs into the car harness. See if mpg changes. You'll get a CEL due to the open circuit, but at least it will be a constant open circuit and the car will recognize and adjust for that.

What was the source for the remanufactured engine? Are you certain is was built for a prius? (cams, etc). It sure sounds like it's an engine power problem, specially the part about struggling to go uphill. Air intake, fuel and exhaust. One of the three isn't right and is holding the engine back.

I would also check the temperatures of all four wheels after a good drive. They should be slightly warm, but not hot. Any that have a brake dragging will be significantly warmer than the others. I don't think the Gen 3 suffers as much as the Gen2, but if you have a leaky brake system/actuator, it may be applying slight pressure to one or more of the brakes. I'm experiencing this exact problem right now with a 2005. It appears it's leaking actuator is causing a bit of pressure on the driver side front brake, and that wheel is quite a bit warmer than the other three. This car is getting around 33 mpg. I haven't totally dug into it yet, but that is my main suspicion. That wheel's brake pressure sensor was also showing a point or two higher on techstream when the car is just sitting.

 

That was supposed to be a joke.