During the end of my drive home last night, I noticed a bit of fuel smell in the cabin, figured it was from nearby road work. It got strong as I was almost home and as it had just started raining, I realized it must be me. This morning I started the car and opened the hood, and it seems that immediately as the ICE came on, fuel started gushing from somewhere around the right side of the engine block (maybe one of the injectors?) Cut the engine and put into accessory to run an OBD-II scan and it came back with the following -P0420* "Emission converter system, bank 1 - efficiency below threshold" *has been there for several thousand miles, I assume from the aftermarket catalytic converter, got the code to subside long enough to get my inspection pass <1500 miles ago) New codes: -P0171 "System too lean, bank 1" -P1455 "Evap emission control sys leak detected(gross leak/no flow)" -P2195 "Heated oxygen sensor 1, bank 1 - signal stuck lean" I didn't get to pin down where the leak was coming from as it was gushing so fast and I immediately reacted to turn off the engine.
All those error codes, as well as your observations, point to a fuel line / fuel system failure somewhere in the engine compartment. Make sure to have a fire extinguisher handy and someone assisting you / keeping an eye on you as you work on finding its source.
The fuel line comes up the firewall toward the midline of the car, and connects to the fuel delivery pipe that wraps around that end of the engine and along the head where the injectors fit in. You might want to prepare by removing the windshield wipers and cowl (see instructions at the start of pretty much every kind of work toward the firewall or the back of the engine) so you will have easy visibility back there, before sending any more power to the fuel pump to see where your gusher is. A tool you used to find in auto parts shops in the old days was a "remote cranking button", nothing more than a hand-sized grip with a button in it, and a cable with two clamps on the end. You could clamp it to the battery and the starter solenoid of an old car and use it to crank the engine while standing around front. You can probably also use that, after finding and pulling the fuel pump relay, to jump across the right terminals in the relay socket, so you can run the fuel pump just when you hold the button. There probably will be small sparks inside the button, so don't hold it right in the cloud of vapors when pressing or releasing it.
I'll take your advice about removing the cowl, etc. and see what I need to do from there. I'm about to work on it in a moment so I'll upload a photo and hopefully that will help shed some light on what needs to be done
Any recent work on the car, in particular, new spark plugs or injector(s) replaced? Possibly whoever did that took the injector hoses off for better access and one (or more of them) wasn't fully seated and has now popped off?
Yes, it's been several months, but I changed the spark plugs and PCV valve a while back. Also was digging around in the same area before installing the upstream o2 sensor around the same time. I was suspicious of that because of the location, but felt like that was wishful thinking. Because of your comment I decided to clean the injectors using the diy method of pulsing through carburetor cleaner with alligator clips, then put new seals on, and it worked! The injectors had been seated improperly and the seals were pretty degraded and puckering. Probably because I didn't know the proper technique to insert the fuel injector or that the seals needed to be lubricated with fuel (or spindle oil) first. Found a helpful thread here in which someone posted a few diagrams on how to insert properly. Surprised that it took this long to see the consequence of that. As for now, at least I've got her back on the road. She lives to see another day! Thanks All! I've now driven about 30 miles and everything seems alright. The new codes were cleared and haven't popped up again. I didn't let it run dry so hopefully I've avoided damage to the fuel pump.
Congrats! When I first saw your thread, my first thought was fuel injector seals, but decided I was jumping to that conclusion too quickly. Guess I gotta get better at trusting my first thought?
Yeah, I posted those diagrams with the aim to help people get that right the first time ... I'm glad that (a) it took so long to see the consequences in this case, and (b) the consequences were inexpensive and survivable this time.
With the most essential ingredient being a Prius owner that knows how to turn a wrench and is comfortable with working on their own car as per PriusChat guidance, which requires significant skepticism/critical thinking to sort through all our comments.
Yeah, this was so much easier than figuring out my p0420 code ☠️ there are so many threads out there for that one, making this seem very straightforward.
I kind of expected to get better fuel economy after cleaning the injectors and changing the seals. So I'm wondering if maybe there's something still going on. Is that a cause for concern, or am I just anxious? What would be a wise next step be to do due diligence?
Cars these days are pretty good at compensating for dirty injectors. If your Prius was still able to arrange for the right amount of gas to hit each cylinder, even if the signal to do so would have sent much more on a normally working injector, then cleaning the injector likely wouldn't make much difference. You might not even be able to detect the change. Back in the day ( before top tier gas) I had a 1987 Mazda 323 with dirty injectors. That primitive (relatively speaking) computer was not able to compensate, and cleaning the injectors increased the fuel economy from roughly 24 MPG to 27 MPG.