Quick and dirty rebalance...

Picking up a very low mileage (52k) 2005 prius this week that was in a city government fleet till it's catalytic convertor was stolen...purchased an replacement cat pipe, denso o2, OBD-II bluetooth scanner that works with the Dr.Prius app, and a HLG-80H-C350A to use as a grid charger. I have a 12v 6a trickle charger to hook up to the traction battery fan, other than running some inline fuses and multimeter, is there anything else I need here?

 

I can check the modules with Dr. Prius right? Clean corrosion on buss bars...got it. Fingers crossed for multiple warning stickers...they did a 10min idle power with high beams, AC, and fans full blast up by request, had a check engine light (no cat) but no RTOD...some of the other priuses they had up for auction did have RTOD however.

Yes I have Motul 8100 ECO-clean 0w-30, Bosch 3325 filter, some DOT4, and Redline D6 ready to go for when I get home, will likely replace the air and cabin air filters for good measure as well...maybe even a set of those new NGK ruthenium plugs for the fun of science! I like to always start with a clean general maintenance slate with any "new" used vehicle.

 

Just picked it up today, forgot to bring the OBDII module with me but after installing the new cat on o2 sensor I filled up the tank, inflated the tires to 44psi, and drove 130mi back home...total trip average according to the consumption screen was 55.7mpg?!?! I thought the EPA rating for highway was 45?? Battery was going back and forth between 6-7 bars from blue to green so I'm assuming that's a good sign? Air filter is clean, motor oil is clear (though a 1/4" over the full line on the dipstick), tires have tons of tread (Goodyear assurance). I'll report progress tomorrow once I scan it and clear the check engine light. Is there some sort of ECU reset-learning procedure I need to do so it can trim fuel now that the new cat is installed?

 

Yeah I'm gonna do the oil today, I found a receipt in the glove box and it looks like the change was done 2 years ago...the listed odometer mileage was only 900 mi less than it is now, crazy! Most of the highway was flat but there was some gentle grades that went on for a quarter mile or so here and there.

 

Did the full life expectancy test on the Dr Prius app...90% is a new pack apparently, so 88.68% is pretty darn good I think! One thing I noticed is that module #7 is consistently lower than the rest, but I don't think being off by 0.13v from the best looking one (module #1) is too bad, but the internal resistance reading makes me think I'm going to have to clean some corrosion...10-15mohms is ideal I've read.

Amazingly, that was BEFORE putting the new cat in and clearing the ECU...had to have been running rich with no o2 sensor, and yet still crazy efficient. Oil changed out yesterday, interesting that the Bosch filter I got is longer than the OEM one? Threaded in fine, so I guess it can't hurt to have a little extra filtration media.

 

Update: cleaned the MAF sensor and throttle body along with replacing the spark plugs with new NGK ruthenium ($11 each, oof). Noticed some rat pellets on the valve cover, fingers crossed I don't have to deal with chewed electrical wires at some point!

Idle is smoother now, transition between electric motor to ICE is not as obvious (I don't feel it through the car vibrating as much), and it feels like the motor has a bit more power when accelerating or maintaining speeds on positive grades.

Just came back from a 75mi round trip highway excursion that has about 1200ft of elevation changes...54.2mpg. I've got to say I really wasn't expecting this kind of mpg, especially since it's using winter gas formulation which is terrible for efficiency in any other car I've ever owned. Next test will be post rebalancing/corrosion cleanup.

 

Good point...what about maybe just spraying CRC contact cleaner on the posts and bus bars and a light wire brush scrub without removing them? I've had great success with that stuff fixing gremlins on 40 year old circuit boards in home stereo gear.

 

Just did that...ECU update in 06', recall 60C (??) In 06', recall 90L pedal modification in 10', A0N REPLACE HV ELECTRIC LSC in 11' (inverter water pump?), C0T - STEERING SHAFT in 13' and that's it. So it looks like its all recalls, and scheduled maintenance was done by the county in house.