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Forum namePerformance/Engine
Topic subjectWhat is this vacuum line on the 99?
Topic URLhttps://forums.2gnt.com/dcboard.php?az=show_topic&forum=i5&topic_id=123793
123793, What is this vacuum line on the 99?
Posted by ez, Jan-30-09 08:13 PM
It comes off the intake mani, passenger 3 prong connector. Then dives underneath the car. I *think* it's going past the fuel filter/stock FPR and towards the gas tank. On a 95, I think this just goes to the FPR on the fuel rail. The 99 doesn't have vacuum going to the FPR though.

My Diagram (it's marked as "?"):

Photo of me holding the line, red arrow shows where it disappears:

My underhood diagram (what?)

EDIT: someone else's took a better pic



If I'm reading that diagram right, that 3 prong connector goes to the EGR solenoid (I understand that one), and "VSC" and a "LBP". LBP has something to do with EGR as they are interconnected.

I thought the only thing going to the EVAP system was that one line of the throttle body, but this other line has me so confused. Is the VSC for cruise control? I don't have cruise control, so this would explain why my middle port on the 3-prong connector is blocked.

What happens if you block this line? How do you 99 guys that went turbo deal with it, does it have anything to do with CEL 31?

EDIT again: Dan talks about it here too:
http://forums.2gnt.com/dcboard.php?az=show_topic&forum=8&topic_id=75347&mode=full
123802, RE: What is this vacuum line on the 99?
Posted by teklein, Jan-31-09 08:40 AM
EZ, that line runs to that location on mine too (98).

I cant verify, but I believe it is for the evap system from what I have heard.

And I have no CC, the middle port is plugged on mine too. I took the vac line that runs to the TB and put it on there to clean it up a bit.

My friends car had CC, and his CC went to our plugged port.

Laters!
123803, RE: What is this vacuum line on the 99?
Posted by Slo2g, Jan-31-09 08:45 AM
I just capped mine off. Don't know about the codes because I already had a CEL. Its all evap related though I believe...
123804, RE: What is this vacuum line on the 99?
Posted by eclipse982nrRST, Jan-31-09 08:58 AM
Originally posted by Slo2g
I just capped mine off. Don't know about the codes because I already had a CEL. Its all evap related though I believe...


I believe its for the EVAP system running to the tank. I could be wrong though. Good post though, Iam curious to find out what it really is for sure, so I can cap mine off.
123805, RE: What is this vacuum line on the 99?
Posted by RoninEclipse2G, Jan-31-09 10:18 AM
Yeah, it's for the evap purge valve so that the fumes get sucked back into the intake instead of going up into the air. if you cap it you'll get an evap leak code
123809, RE: What is this vacuum line on the 99?
Posted by eclipse982nrRST, Jan-31-09 12:47 PM
Originally posted by RoninEclipse2G
Yeah, it's for the evap purge valve so that the fumes get sucked back into the intake instead of going up into the air. if you cap it you'll get an evap leak code


Doesnt matter to me, I dont have the stock ECU or EVAP system any longer.
123991, RE: What is this vacuum line on the 99?
Posted by Nemo, Feb-09-09 10:06 PM
I'm getting a CEL P0442 and was told it's a hose running from the tank to the motor.
123992, RE: What is this vacuum line on the 99?
Posted by halfasss101, Feb-10-09 12:16 AM
The line that is coming out of the left side of that 3 way split on mine goes down toward the alternator and i can't see it anymore. But my diagram on the underside of my hood shows it tying into a line and it goes to the evap canister.