Any idea where this goes? Phantom Vacuum line (1 Viewer)

[BigBlueLC]

Hey everyone, had an issue with a rough idle and electrical gremlins, resulting in stalling out about 100 miles from home. Got towed to a local Toyota dealership, who couldn’t diagnose the problem, so towed back home to work on it myself… popped the hood and found this hose with a plug in it. I for the life of me can’t figure out where it plugs back into. Any ideas?

Dealer replaced the fuel regulator, which looks new, but they seem to have forgotten to reroute whatever hose this is:

 

[paulzak]

Trace the hose to the hard line then follow it. What does it attach to? Consult the vacuum diagram on the hood and you may figure it out quickly.

 

[NLXTACY]

Kinda looks like it’s a test hose. But whatever it’s connected to needs to be properly routed.

 

[Grandlooser]

Honestly that kind of looks like the return line location from the FRP itself but would be leaking a lot of fuel if that was the case. The place where it attaches is right there where the return goes though. Is the FPR outlet capped? dont go to that dealer again lol.

 

[Irish Reiver]

Its possibly a frig to try and plug the #1 bypass hose which runs from the cylinder head to the throttlebody. Maybe someone just put a piece of hose on the pipe at cylinder head and plugged it.

 

[BigBlueLC]

Thanks for the replies so far. Ran the engine and didn’t detect any suction, then blew into it and could hear air flowing out somewhere. Can’t seem to find anything that looks remotely like this on the vacuum hose diagram.

 

[Irish Reiver]

It could be a home made extended diff breather. That would be easy to trace.

 

[paulzak]

Thanks for the replies so far. Ran the engine and didn’t detect any suction, then blew into it and could hear air flowing out somewhere. Can’t seem to find anything that looks remotely like this on the vacuum hose diagram.

My recollection is that the hard lines are dipicted on the hood vacuum diagram. It looks to me as though your hose connects to a hard line but the picture is a little unclear. By a process of elimination, you should be able to figure out what isn't connected.

 

[mudgudgeon]

Hey everyone, had an issue with a rough idle and electrical gremlins, resulting in stalling out about 100 miles from home. Got towed to a local Toyota dealership, who couldn’t diagnose the problem, so towed back home to work on it myself… popped the hood and found this hose with a plug in it. I for the life of me can’t figure out where it plugs back into. Any ideas?

Dealer replaced the fuel regulator, which looks new, but they seem to have forgotten to reroute whatever hose this is:
View attachment 2779322

What's the diameter of the blue plug? Looks like ¼" ?

There's no vacuum lines under the plenum bigger that 3/16" (internal) on my Aussie '93.