Engine behaving strangely and popping hoses off intake manifold

Welp, when the purge valve is open, that's not just fresh air being brought in; it's being brought through the vapor canister, purging it of the collected fuel vapors. So what's filling the hose and manifold is a nice mix of air and fuel vapor, so any hint of backfire might be enough to make that do what it'll do.

 

So it's been one week since my last post and one tank of gas. I let the tank get down to one bar (on a very hot few days) before refueling to see if the issue would reoccur... it did not. It has been perfect, so I think this may be fixed. I am driving the car to Phoenix from Southern Indiana in June, so that will be the ultimate test.

I think this saga might be over. I'll keep putting miles on the car and update if I hit any snags.

 

Thank you so much to everyone who contributed to this thread.

Especially to OP for documenting everything with every details and lots of pictures without quitting...

I started observing an RPM surge just past week. It only happened two times so far but I am on it.
This could just be my problem as well.

Anonymous & Protrex, did you guys experience this ever again after replacing the purge valve?

 

I started having this issue a month back and replaced the purge valve (and also cleaned EGR cooler and system). The problem has not come back so I think it is solved. I spent under $100 in parts and then a little bit on chemicals. Dealer quote over the phone was $1200 to do this with the related tech bulletin. : O

 

I didn't have any popping hoses. Just the surge twice so far. That's it. And I don't think everyone with this issue experienced hoses coming off...

 

themzlab, could you say how often the issue was presenting itself? Was it happening every time you drive? / Any specific conditions you may recall?

Thanks

 

No, it was not happening every time I drove, it is my commuter and I have a 35 mile drive each way. It may have been once or twice each week so it only happened a few times before I decided to park the car and fix it (the final straw being the hose popping off). I never noticed it or it never happened on the freeway, but happened after I got off the freeway on the slow part of the drive. The first time was in the morning on a foggy day during the first 10 minutes of the drive and at the time I thought it may have been related to the cold and high humidity, but in hindsight that was probably just coincidence and nothing more. Mine is still OK.

 

@anonymous since you're the only known member to disassemble the valve.

Did you notice significant stiction in the assembly that would warrant using a solvent or cleaner before lubricating?

If one were to try lubricating an assembled valve, would it be best to apply lube to both orifices, or only to the white or black ports?

Also noticed in one of your above posted pics that the curved baffle/filter(?) may have some type of carbon build up?



Thank you!

 

Had this issue on our 2015 Prius V, revving up & down (up to 3000 rpm, back to ~500) while coasting, then sometimes revving up high while at a stop, and not shutting down the engine when it should even with a full battery. It would come and go, and sporadically throw the P0171, P0441, P0455 codes sometimes together or sometimes a subset. Took the car to the local dealership that charged a couple hundred dollars to do a "diagnostic" which when pressed about the details ended up being plugging the car into a computer for an hour then reading the result. The recommendation there was a charcoal filter replacement quoted at $1200 which I balked at. They had no explanation for why that would help with the symptoms I was seeing.

I'm so happy I found this thread and wanted to thank anonymous for finding and thoroughly documenting it all!

$85 for an EVAP purge valve and a bit of time pulling off the air filter assembly, swap in, and no problems since.

Really eroded my trust in Toyota dealers to understand and fix the vehicles.

 

Just to refresh my memory: evap purge valve is that little gizmo bolted to right side of intake manifold (as you stand at front of engine bay)? A hose runs from it to a spigot at around 6 o'clock on the round bit of intake manifold, that throttle body bolts to?

 

2010 Prius, 167K, got PO441 code. New EGR cooler and OCC at 155K, did research and started with a new gas cap. This thread very helpful! Cleared the CEL but PO441 returned after about 3-4 hours, been doing so for one week now. Looking at the EVAP purge valve now (Toyota calls this "Valve Assy, Vacuum Switching"), looked around Hawaii and it's out of stock at all the dealers, Amayama site says 25860-37020 "no deliveries to America" but does show 25860-37040 which looks to fit in same place next to intake, below air box. I wonder if this is a new, improved part? The 25860-37040 does not show up in any American parts supplier sites. Any ideas about this part?

 

Any wrecking yards in Hawaii with Prius?

 

I’ve checked in past and only found Gen 2. Will check again, good call, thanks!

 

Auto wrecking yards in paradise is a little depressing, kinda like looking up Disneyland on Google Maps.

 

To close this one out, I ended up getting the purge valve from one of the discount (!) parts suppliers on the mainland. Got it Wednesday and installed it today, so far no CEL bit there is still a permanent code hanging.

Got this from Amayama:

You just received the message from Amayama Trading Co. Ltd.:
Inquiry #11146177

The correct part number for the VALVE ASSY, VACUUM SWITCHING is 25860-37020. There is no substitute part number listed so we cannot confirm if 25860-37040 is compatible with your vehicle.

Cheers

PEH

 

You have to drive through at least three full start/warmup/stop cycles to be sure the code is gone. That’s how OBD works. But hopefully all is well and the last code will clear after a few more cycles.