Alright, so here's the back story. Prius has a new battery pack as of 20k miles ago, had a new aftermarket catalytic converter installed about 35k miles ago, and the downstream o2 sensor (cheap aftermarket unit) was replaced along with the catalytic converter. Went on a 3500 mile road trip and noticed it was a lot more difficult to get 40-45mpg on the highway, it was dipping into the 30's and the P0420 CEL kept coming on in the morning after I'd clear the code the previous day. Filled the gas tank 2 days ago and noticed yesterday that the ICE would never stop idling. It would idle normally to recharge the battery, but on the display once it stopped indicating it was recharging, the idle would surge up and down and up and down until the battery needed recharging again, and then it would idle normally again. Tail pipe smells pretty rich, driving it even around town at 35-45mph where I'd previously get 40-50mpg, now gets me around 30mpg. Any ideas? Could my primary o2 sensor be bad? Fuel mixture could be off and "poisoned" my new cat converter? Bad downstream o2 sensor? Bad clogged cat converter?
Some questions: How much oil does your Prius burn? When you say a new hv battery, a brand new from Toyota battery? Do you have a way to monitor what the o2 sensors are reading? Any dash lights? Cleaned the MAF sensor and throttle body? We’ll need a bit more info to help with troubleshooting . Good luck and keep us posted .
When you say “new battery pack” do you mean factory new, or rebuilt? I don’t know about aftermarket cats but aftermarket O2 sensors are a mistake. You should go with Toyota branded or OEM Denso for those. The Denso sensors are reasonably priced on Rock Auto.
It burns about a quart of oil every 350ish miles or so It's the aftermarket new battery pack from one of the members here in PriusChat http://www.newpriusbatteries.com/ I have torquepro and an obd2 bluetooth adapter, if there's a way to monitor o2 sensor signals, I don't know if it Only dash lights are the CEL for the P0420 cat converter low efficiency code
You’re burning so much oil that the cat is clogged and that’s why the error code is present . With how much oil it is consuming, the egr circuit should be cleaned stem to stern if it hasn’t been already. If you go a bit slower, does the oil consumption subside some? Good luck and keep us posted .
Hey Ray, remember the Gen 2 doesn't have an EGR system. Perhaps you meant the PCV? Also, maybe it could benefit from an oil catch can. That is officially twice as much as Toyota would recommend doing something about it. It is cheaper to find a nice running low miles engine than it is to strip the engine and replace rings, pistons, etc.
Yeah . The PCV valve needs to be checked. That’s a lot of oil though. I’d love to see a borescope of the pistons as I bet you could almost pass light through the gap.
WHAT? That's not burning oil, that's pouring it right through the engine. You sure you've got the drain bolt installed? <kidding> Seriously, start researching a used engine swap and see if that's something you want and can deal with. Doesn't Colorado have emissions testing? If so, I don't see how you'll continue to pass with that burn rate. GOOD LUCK!
I'll go ahead and replace the PCV valve, it's a cheap item and it probably needs to be replaced anyways. Isn't techstream a toyota dealership thing? Or is there a consumer version out there? Fortunately most of Colorado doesn't have emissions testing, it seems to be mostly in the Denver area. I'll look into swapping a new/used engine in
Techstream is what dealers use for diagnostics . But you can buy a J2534 protocol cord off of Amazon that has Techstream as part of it. A lot of posts about it as well as how to use it.
