Help identifying these hoses. (1 Viewer)

[Gunrunner235]

I am still trying to fix my P0171 code. Found that 2 bolts were missing from up plenum, no more leak from intake, but I put a bore scope under the upper manifold and noticed these 2 hoses, one had the hose on it the other did not, the other end of the hose was attached to nothing, I found another hose seemed like it was attached to the block a little under the manifold, where do these 2 hoses go to and what do they do? I have my EGR already bypassed, so I’m wondering if these are causing my vacuum leak or if I can just plug them up. I have attached a photo of the 2 hoses I am taking about.

 

[Irish Reiver]

Its one of these two if i remember correctly. There are two of those thi k vacuum hoses in there. If one is cracked the second one is also likely cracked. They were about $20 each from McGeorge a couple of years back.
90910-05212
90116-10169

Edit - the metal pipes have two normal vacuum hoses that go to the TVV on the cylinder head

 

[Gunrunner235]

Ok, next question what is the TVV ( I assume some vacuum switch) and could those 2 port coming from the upper intake be causing a vacuum leak?

 

[Fj80oregon]

Google is faster than waiting on us. Just saying! The TVV (thermal vacuum valve) the TVV opens up when warm allowing the purge port on the charcoal canister to dump into the purge port in the throttle body. This way, when the engine is warm and in closed loop, the engine can manage the extra vapors properly.

 

[Gunrunner235]

And if the ports on the intake are open or don’t have the hoses attached could this be the cause of my P0171 as a vacuum leak?

 

[Fj80oregon]

And if the ports on the intake are open or don’t have the hoses attached could this be the cause of my P0171 as a vacuum leak?

No

 

[Gunrunner235]

Ok. Guess I need to keep looking for what’s still giving me this code

 

[Malleus]

What year is your 80? Are you certain you have a P0171? I've attached the list of failure codes for you, and the solution links in the FSM.

 

[Gunrunner235]

Yes, it’s the system to lean in bank 1. Have been trying to fix it. Thought I had it fixed when I found that missing bolt the CEL turned off and then after about 10 miles came back on. Getting to become a PITA. Replaced hoses, the front o2 sensor, fixed the missing bolts, bypassed the Erg with the “test kit”, fixed the hoses under the plenum, idk. Truck runs fine tho, I did a reset after running those hoses under the plenum to the TVV, CEL hasn’t come back on but I didn’t drive it just idled in my driveway