EVAP Service port location

I need some expert help locating and/or confirming the EVAP service port for the 2006 X-Runner 4L V6, 1GR-FE.

I have been chasing an EVAP system problem for the last few weeks. The ECU has been throwing the dreaded P0441 and two others; "leak" and "small leak" - I cannot remember those two other codes off the top of my head.

The gas tank, canister, and purge valve (90910-ac001) have been replaced over the last year. I cleaned the MAF with MAF sensor cleaner, and cleaned the TB with TB cleaner. I have not replaced the Air Switch Valve (MX084860-8230), but I did test it to see if it switches, and it appears to be fine.

I do have a smoke machine - the Stinger Pro 2, but for the life of me I cannot find the EVAP Service Port on my truck. There is no green cap or anything that is easily marked.

All I see is what appears to be 2 ports; one I am sure is for the AC as the line it is on connects the AC condenser. The other port, I would imagine, is the EVAP service port. My smoke machine does not have the proper connector, and the line this other port is connected to is not easily accessible (no T connectors to pull away to connect my machine.)

Can someone me locate the evap service port? A picture? Or do I have another option; i.e., just unplug any of the evap hoses that would be under vacuum and smoke away?

 

Yes you can just tap into the evap line anywhere there is soft rubber. If there is a place close to the factory port great, if not, just tap in anywhere and send the smoke both directions (like up toward the engine/purge valve and then the other direction down toward the gas tank/canister)

 

If you have a smoke machine you should plug in right before the purge valve on the engine. Hope you don't live in the sticks, I've seen the lines on top of the tank chewed through by rats.

 

Thanks for the replies.

Even though the Stinger Pro2 has a 1psi regulator, I was a little nervous about plugging it into any given hose. I don't know what could break (if anything) if the pressure was too high or if it was possible to incorrectly connect it.

I will go ahead and connect it to the hose before the purge valve this week and see if I can track down the issue.

 

I am back with some results.

I have smoked tested a few times over the weekend. The smoke is spewing out near the top of the filler neck when I check from underneath the truck.

The gas cap is only 6 months old, so perhaps just the luck of the draw and replace it again? I have not been able to find any other type of seal that part of the filler neck at the top. I do see a seal which goes at the bottom? Even so, that area is smokeless.

Any additional thoughts?

 

You could be seeing smoke come out of the canister vent valve. One side of the vent valve goes to the canister (obviously), the other side usually goes to a little filter (fresh air vent). Sometimes the filter is mounted up high to keep it away from the ground.

Is it coming from the cap/filler neck or just a random hose that is near the filler neck?

This is where smoke testing can get a little tricky. You have to command the vent valve closed (either with a scan tool or jump power to the connector) and keep pumping the smoke in. At the very least You can pinch off the fresh air vent hose (between the vent valve and filter) and kinda narrow it down.

I'm not too familiar with how the vent valve/filter is set up on the x-runner. Maybe someone can jump in with a diagram.

Remember the vent valve (vent to fresh air) is statically open at all times. It only closes when commanded by the pcm during testing and for pulling vacuum on the system.

If the vent valve is closed and it's still leaking at the filter then the vent valve is not sealing and needs to be replaced.

 

From what I can tell, right at the top of the filler neck. It almost appears that there could be holes/cracks near the top of the filler neck given the amount of smoke. It is hard to tell since I am looking up at it from underneath the truck.

I don't see it any smoke (for now) coming from any other hose or connection.

I do have a scan tool where I can read and clear codes (TOAD software from Total Car Diagnostics). I will have to check with them if I can command the valve to close.

I have attached a marked up copy of the EVAP system for the 1GR-FE. This is the first time I have had to do something like this. You can see that I am injecting smoking after the small vacuum surge tank where it says EVAP Service Port.

However, I do not see this type of connection - I am simply plugging in my smoke hose to what is labeled the Purge Line since that is all that I see after the surge tank; i.e., a hose that goes into the firewall.

So my options are to command the VSV on the canister or at least pinch the hose between it and the filter?

Perhaps the leak is small at the VSV and if it is not commanded to be closed then gobs of smoke will be near the filler neck.

Thanks for the help. I feel I am very close to solving this myself rather than taking it back to my mechanic.

 

Is there a small hose that piggybacks the filler neck and goes up toward the fuel door/bedside? If there is then it's likely that air inlet line that comes from the canister.

Yes pinch it off at your blue mark. If it's sealed up everywhere when the line is crimped then a vent valve (They call it a vsv-ccv) is the likely suspect.

But the quote/un-quote correct way would be to command the ccv closed with an appropriate tool and then look for smoke. That way you know you've at least got pcm control and you're looking for a mechanical problem. Like a dirty vent valve that can't seal

Also, what they're calling a vsv for evap up by the engine is a purge valve. Use a hand-held vacuum pump see if it bleeds down. Tap on it with a screw driver. They can fail intermittently. But good ones can be expensive..

 

I believe there are three lines, all metal. I have to go look again after work.

I will try to pinch off the hose later tonight. I have not heard back about the software and tool I have that can command the PCM to close the valves. Hopefully I will hear something within the next day.

I already swapped this out for a new OEM one. $90. I am not sure the old one was the problem, but at least it is replaced.

 

Final update.

The TOAD software cannot command the ECU to open and close the valves. At least I can still read, clear, and data log.

Since I have no way to fully seal off the valves, it was difficult for me to know for certain what the issue truly is. I smoke tested a few more times and I couldn't see smoke leaking from hoses, so at least that is something to check off.

I ultimately decided to take it back to my mechanic where they have a better scan tool and the issue ended up being a poor purge valve (VSV for CCV) on the canister. All warranty work thank goodness.

 

Ha ha. I lied. This is the final update.

So after a couple of days the CEL came back on again and the code this time was P0456 (small leak).

At this point the canister+VSV was replaced again, and given I had replaced the other purge valve the last thing I could think of was bad vacuum hoses.

I took a few of the hoses off and many were cracking from the inside out. The cracks were ever so small and you would have to look at the inside of the hose. There is nothing visual simply by looking at them when hooked up regularly which is probably why they were never replaced.

I presume these are the original hoses (I am the 3rd owner) and with a 140k and being 12 years old, I simply replaced them with bulk vacuum hose from Orielly's.

It has been over a week, and I am free and clear.

Moral of the story:

Triple check your hoses, yo.

 

Did you have to drop your tank everytime you checked stuff and smoke tested?

 

No, I did not drop the tank when I was looking at the hoses, lines, or when smoke testing.

The smoke testing didn't really help me this time around, since it there was no way for me to command the valves to close, so the smoke had places to escape.

Since a "small leak" in the world of EVAP is honestly ridiculously small, any place that allowed smoke to exit wouldn't have highlighted the bad hose.

I figured that the charcoal canister and VSV value has been replaced, the next best thing to check is the hoses. And sure enough. Free and clear since then.

 

Hmmm. Ever since I pulled the bed and boxed my frame I've been throwing P0441 and P0445.
I find it an odd coincidence for it to just randomly happen after removing the bed. Upon reinstall I will say that we got held up on the filler neck and I had a bad gas smell offroad for the first time after. But ever since I've never smelled it again. Code always pends and CEL pops up like once a week. Idk the first place to start. It has a newer gas cap lol