Underpowered. Uneven response to the gas pedal.

Hello,

It seems that I need some advice from the hive mind.


Prius gen 2 2009. 286K miles so far. Original traction battery, engine, and basically, everything else.

I got it for $500 and have used it for almost two years now. Right after purchase, I changed tires, repaired MFD, replaced faulty HID lamp driver, converted interior lighting to LED, repaired rusted wheel arch, changed PVC valve and spark plugs, and was happy since. P1116 and P0420 are showing up periodically and then vanishing by themselves. Normally 40-45MPG (from the reading from the display).

It was just recently that the car started acting up:

Periodically the car feels unpowered, the reaction from the accel pedal is slowed downs, and sometimes there is a delay, and just after 5-7 seconds, the engine starts revving.

A couple of times, the car was running just on the battery, and then red triangle + P3190 was thrown, but fortunately, after IGN off-on, the car was able to start again.


What I’ve done so far:

-Cleaned MAF sensor

-Cleaned throttle body (unfortunately can’t reach throttle position sensor as one of the screws stuck)

-Cleaned fuel injectors

-Applied CRC intake valve cleaner

-Cleaned minor corrosion from the traction battery.

-Charged 12V battery using a wall charger.

None of these actions helped solve all of the problems, although there was no red triangle of death for a couple of days now (but the problem with acceleration is still there).

Under suspicion also a gas fuel pump, so I am thinking of getting a tank from the junkyard, but I wish there is a way to check the fuel pump (pressure?) to be sure. Also thinking of checking and maybe cleaning the catalytic converter.


Any ideas and recommendations? Thanks.

 

Trying to monitor the system with a techstream during the idle mode, and saw a few misfires on different cylinders. Oddly there are no misfire-related codes. Long-term fuel trim is from -2% to -6% typically.

 

Anyone knows how exactly the fuel pump on gen 2 operates? Are there any pressure sensors? How does it know when to pump? Or is it just pumping "blindly" while the car is in IGN ON? Is there a correlation between throttle position and the fuel pressure, or the pressure and pumping is constant no matter what?

 

Thanks!

I did. I disconnect the 12v battery in almost any case when I am working on the car, especially on the fuel system, as a precautionary measure.

The “cleaning procedure” was simple and not extensive. I let the bottom part of the injector soak in the isopropanol first, then in the ethyl acetate for a short period. Then I wiped the solvents and the residue with Q tips, and pretty much everything became reasonably clean upon visual inspection. I checked the solenoid conductivity (all were 14.2+-0.1 Ohm range), applied 12 volts, and had a satisfying clicking sound. I tried to blow any possible debris from the injector top with compressed air and finally used some WD 40 on the bottom and top injector’s ports.

Then I put new O-rings (Viton) and counted on the fact that the injectors were clean to begin with. After adding a CRC 1-tank treatment, I made peace with myself and decided not to do a volumetric injector test per service manual recommendation.

Thanks for the suggestion, and I will try to exercise the traction battery with a DIY grid charger (the price of the ones on the market don’t make sense to me).
Although, the traction battery does not look that bad at first glance – I regularly monitor the voltage difference and SOC in Techstream, also taking into account that with all the mentioned occasions when ICE quit working, I was able safely to drive and pull over solely on the traction battery charge (2-5 minutes of driving@15-30mph).

Detroit

 

Recently I put the car on the lift and found a leak from the transmission. It is hard to track the leak location, most likely from the transmission seal or the parking motor assembly seal. The slow one. I’ve previously seen occasional oily spots under the car but thought this was an oil drip from the oil pan.

I drained the transaxle fluid, and it was 3.01 L (gravimetrically, density 0.84), and refilled with ATF WS, 3.61 L (gravimetrically, density 0.85). There was a little bit of ferromagnetic slush on the magnetic plug, but nothing substantial. Also changed the oil and filter (it was due), and checked the plugs – they were ok, although there were a few drops of oil in the wells, I might need to change the valve cover gasket soon.


After this car's behavior returns to normal, also I get 50-51MPG (from MFD trip info page) on ~100 miles-distance - I have never seen these numbers that high before.

Thanks, edthefox5 for the suggestions, I will try to clean the cat converter with some organic acids and possibly with the steam cleaner.

The traction battery is most likely weak as well, but from the techstream data, cells react to loads equally so far, I mean equally weak, also there were no battery codes.