This is kind of a continuation of this topic (if you're interested, you don't have to read it), but I felt it was worth making a new one because enough things have happened/changed since then.



TL;DR - I think I narrowed down my issue to either my Purge Valve or something in relation to it, but I cannot find the proper part number so I can get an official replacement from the dealership. The reason I think it's the purge valve is because I put gas in it for the first time since all of the car nonsense happened before and it wouldn't start at first, then it started but it idled HORRIBLY, I opened the hood and it smelled lightly of gas, and then I turned it off and gave it a moment and started it up again and it started and rode just fine. Also, in the 100k+ miles I've put on this car, I've NEVER topped off the gas when filling it.



You can stop reading there if you'd like, but for more context and information you can keep reading.



So earlier this year I had an issue with my purge valve, I've since then forgot what the code was but I took it to the mechanic and he replaced the purge valve and it fixed my problem more or less and I was able to pass my emissions. Then a couple months ago my check engine light along with the traction control light came on and my code read P0171. I took it back to my mechanic after checking everywhere for a leak and he replaced my MAF sensor even though I told him it wasn't the issue (i told him the MAF error code was because I drove with it unplugged). Sure enough the code came back. I told him I'm hearing a hissing noise and ticking noise near where the purge valve is and my gas mileage is horrible. He tells me he cleaned out the throttle body and that should do it because he couldn't find a vacuum leak. Of course that's not going to fix anything so I stopped going to him after that and basically left the car alone. Besides, at this point the check engine light turned off and came on and is currently off again. Gas mileage is still crap.



I think the light goes in and out because I noticed the hissing noise from the purge valve area was kind of going in and out, so I was wondering if the two are linked. I found some people say that a messed up purge valve could cause a P0171 but nothing super concrete. I tried pinching off the hoses going to the purge valve and the hissing stopped, and once there was a very obvious ticking coming from the purge valve with a corresponding "SS SS SS SS SS SS" kind of hiss. I told the mechanic this and he basically interrupted me crying about how he can only go by what the engine code says (you can tell i'm very bitter about this mechanic, he charged me 400 bucks to replace the purge valve too which I now realize was a complete and utter rip off, ESPECIALLY now that I might have to replace it again myself...)



My concern is this: was my old purge valve bad and did the mechanic replace it with a crappy part that is now going bad as well? OR is there something else going on that could be causing the purge valves to go bad? This is where I could use the advice, because I don't want to drop like $150 for a new purge valve (unless you can recommend a good quality aftermarket one for cheaper) and it turns out I need to replace something else as well.

 

Suggest you review websites at the link below to find all items that can cause the P0171 code.

https://www.google.com/search?q=P017...t=gws-wiz-serp

A bad purge valve by itself typically just sets a trouble code. The purpose of the valve is to control the flow of stored fuel tank vapors into the engine to be burned. The valve is either open or closed. When open there is a controlled flow of air into the engine not a leak to the outside as in a cracked hose.

The fuel vapors are stored in canister containing charcoal.

If you smell fuel it may mean there is a crack in the canister, cracked hose, etc. Any valves are typically mounted to the canister which is in the area of the fuel tank under the chassis. The purge valve may be built into the canister and not separate.

Topping off the tank can lead to liquid fuel getting into the canister making it less effective.

The hissing noise and low MPG would seem to indicate a vacuum leak. Low MPG can also be caused by a failed A/F sensor causing the fuel mixture to be too rich. Both issues are common.

A mechanic could do a smoke test. Here injecting smoke from say heated mineral oil into the engines intake manifold (engine off) or fuel tank and look for signs of smoke from leaks.

The purge valve can be tested. Apply 12v and it should be open. When there is no voltage it should closed. Open or closed.

For parts try Rockauto.com.

Check canister for cracking, cracked hoses, etc.

 

I believe I found the part number by the way, it's 258600V040 if anyone is curious. NO idea why that was so difficult cause it took me like hours to find the official toyota part number.

That being said, does anyone have a proper diagram showing how it's supposed to be connected, meaning which hose goes where? I can't tell if it's hooked up backwards or not.

I'm trying to look at the diagram on toyota's site but it doesn't exactly match what i'm seeing in my engine. The tubes currently connected look like they're supposed to fit the way they currently are (i.e. they seem like they're shaped properly for how they currently fit), but the way the tubes look in the diagram would mean they're shaped differently and backwards.

Is the nipple sticking straight out the same side as the electrical connection supposed to go straight down, and the port sticking straight down supposed to route to the engine?

I know P0171 points to a vacuum leak but i looked everywhere and I couldn't find one, and my mechanic claimed he smoked it and couldn't find one, but he's also a piece of garbage, and the only other thing i have to go by is the purge valve he overcharged me for possibly going bad, because that would explain why my car had that rough start after refueling recently, and I'm told they can throw an intermittent P0171 code as well. He replaced it in august and the issues started late September.

 

For photos of part try other parts sites such as rockauto.com, amazon, etc.

Is this part near the intake manifold area?

Inspect the part in the car now. Does it look like this:

https://www.ebay.com/itm/40294753742...75.c101224.m-1

Or this:

https://www.ebay.com/itm/19525391910...CABEgJXDvD_BwE

One part has a round tube on the end and the other does not.


.

 

I'm showing my car ignorance but I'm not sure what an intake manifold looks like, but I will say it's right next to the MAF sensor, and it doesn't look like either of those. It looks exactly like this:

https://www.oreillyauto.com/detail/c...ge+valve&pos=3

 

I found a picture of the actual toyota part and it looks slightly different than the one that's currently installed (the one he replaced). https://parts.lakelandtoyota.com/p/_...58600V040.html

I'm not sure what that extra port going down is for, like I'm just confused now. I don't know why this part is such a mystery, but i'm almost positive it's what's causing most of my issues at the moment, but I can't find any good documentation about it.

 

You can test your theory the valve is the problem by removing it and plugging both hoses that connect to it.

The valve is normally closed and then has no effect on engine operation unless it leaks When the valve is open it allows fuel vapors to be drawn into the engines air intake hose to be burned.

The MAF sensor is part of the engine air intake hose system. This intake system runs to the intake manifold that bolts to the engine.

When the valve is open the fuel vapors are drawn from a canister that stores them The canister receives the fumes from the gas tank. When the valve is open the engine should still run normally.

If the valve is constructed as in your photos it should not matter which hose is connected to which tube of the valve.

 

UPDATE!!!!

My hunch was correct. So I got the new purge valve and installed it and went to check the codes to reset them, and it turns out there were 2 new error codes that popped up! P0441 and P0455. I KNEW it.

I reset the codes and drove it to the gas station close to the house, no codes no issues. Filled the tank, the car started up right away, no weird crazy engine crap like what happened last time. Drove it for the past several days and finally checked the codes again and everything is good! No temporary or permanent codes! On the fence if I want to go back to the mechanic and see if I can get a refund for the crappy part he put in, or just leave it alone and write a review.

 

Had a similar issue once. Code pointed to the purge valve. Changed out the purge valve as SOP and still had the code. More investigation (smoke test) found another EVAP leak which was fixed but still had the code. Tested the new purge valve and found it leaked (didn't fully shut off). Swapped in old part and code went away. So old valve good, new valve bad and the issue was not the purge valve even though the code pointed to it.

The P0445 code be gas cap.

Drive for a few more days and see what happens. Drive until the fuel tank gets to say 1/4 tank! Every code has its own ECU programmed test procedure that triggers it. This can require so many engine starts, driving a XX MPH for so long, the fuel tank level below say 1/2 tank, etc.