What is this... and is this a problem?

Mike-Halewai · Post by **Mike-Halewai** » 10 Apr 2009, 23:27

My 94 855T is throwing a 2-3-1 code.

In tracking down a fuel pressure issue I noticed that this plastic "stem tree" thinger has a screw in one of the vacuum elbow connection see below...

I noted that the lines ran to a grey plastic "thing" located next to the intercooler hose that feeds seemingly out of the rad support. The funny thing is that the whitish looking vacuum line was busy... hanging out attached to nothing. I attached it back to grey plastic "thing" see below, the picture is care of my iPhone sorry about the lack of quality...

I'm wondering what the purpose of this is ... and if it may be causing some of my issue with a rich fuel mix... and low fuel pressure at idle??

Any thoughts are appreciated.

Post by **MadeInJapan** » 11 Apr 2009, 07:01

A screw in the vacuum tree- hmmm...looks like the previous owner broke the nipple off. No big deal here if it holds air tight and doesn't let air in (there would be a vacuum there). W/ engine running, spray some carb cleaner on that screw and see if it gets sucked into the manifold and causes your engine to surge. If it does, take the screw out and use some RTV sealer to seal off the opening- there should not be a leak there. And you're right that there should be no dangling vacuum hoses- reattaching it to the tree was the right thing to do. After all is attached and there are no leaks, I would reset the computer and see if this makes a difference.

Post by **Ozark Lee** » 11 Apr 2009, 07:22

Just get a new vacuum tree and an O ring. List on the tree is under $10.00 and even the thieves at Rick Hendrick Superior Volvo charged me under $15.00 when I broke mine. The part number is 6842446 for the tree and 978111 for the O ring.

...Lee

Post by **MadeInJapan** » 11 Apr 2009, 07:31

Good point- I forget that on these earlier models, it seems that all of the nipples on the vacuum tree are used. On my '98 two have caps on them. Makes it easier to suck in the Seafoam though! haha.

Mike-Halewai · Post by **Mike-Halewai** » 11 Apr 2009, 12:24

Thanks for your help on this MIJ and Lee. For those prices I think I will just replace the vacuum tree. However, if I should have a 3rd vacuum hose on that top nipple where should it run too?

That grey round "thing" behind the large intercooler flexible hose only appears to have two nipples. Should a third be going somewhere else?

One last question, don't think it's related... That same intercooler flexible hose at the front of my engine compartment has a hole wearing into it. What effect will that be having. I intend to replace it right away. But the volvo stealership want 70$ for it.

Thanks again.

Post by **wheelsup** » 11 Apr 2009, 12:30

I just wrapped black electrical tape around my hole.

Post by **MadeInJapan** » 11 Apr 2009, 15:49

If it sucks in air it will have unmetered air going through, raising the gas ratio as well and you'll probably burn rich- over-all bad for power and gas consumption. get it fixed. Black tape or duct tape may be only a temporary solution. The unplugged nipple at the fan shroud I believe has a line going to, as you might have suspected, the vacuum tree....or it could be the EGR? Is the EGR line unplugged (if you even have an EGR). Pictures are blurry so it's hard to guess about the last few things I posted.

binglax09 · Post by **binglax09** » 11 Apr 2009, 17:36

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Thanks!

Post by **Ozark Lee** » 11 Apr 2009, 19:23

One last question, don't think it's related... That same intercooler flexible hose at the front of my engine compartment has a hole wearing into it. What effect will that be having. I intend to replace it right away. But the volvo stealership want 70$ for it.

It will run like crap.

...Lee

binglax09 · Post by **binglax09** » 11 Apr 2009, 19:50

I have one of those hoses

if it's the front IC hose. shoot me a PM!