Vacuum lines popping off at 15psi. Which ones can I remove?

[tekdeus]

I will upgrade to silicone hoses soon, but was I was wondering which vacuum lines I could eliminate, as they sometimes pop off under boost.

What are the VSV's under the intake manifold for? Part #'s 17650 and 25860?

Also, I was trying to see where hose 17344 goes, and it seems to loop back up to the hardline to the BOV. Is this true?

 

[IJ.]

Small cable ties
(mine stay on at 30psi)

 

[jetjock]

I use smaller versions of the springs clamps found all over the engine. Prior to that I used what IJ said in matching colors for the hoses. Either will solve the problem.

17650 is for the Fuel Pressure UP system. 25860 is for the EGR. The CBA line is indeed missing on that diagram and connects between the two open fittings shown...

 

[ForcedTorque]

My Hose Techniques Silicone hose kit came with a huge bag of small cable ties. I used quite a few, and had probably 100 left. Your post makes me believe that I may need to use a few more of them.

 

[Rennat]

make sure the hose fits over the nipple snugly. you may have put the wrong size on...
but i used a ton of cable ties, makes everything organize and secure.

 

[jdub]

I like the small wire clamps JJ suggested...they look better to me and are re-usable.
As stated, either will work.

 

[tekdeus]

The ones under the intake are incredibly hard to reach. My engine is JDM without an EGR. I still have 2 little electronic modules under the intake with vacuum lines connected to them. Assuming one is the fuel up (which I don't need with my upgraded fuel system), what might the other be? Thanks guys!

JJ, would I find those clamps at an auto parts store?

 

[92nsx]

The other VSV or little electronic modules is for the EGR.

I am also curious about the clamps. I have never seen any in the local parts store. The only two I have came with my BOV.
Any where online we can get them?

 

[IJ.]

I also use a reusable steel clamp on the critical lines like the Boost controller and AFPR but found they're not as good on the tapered plastic fittings on the BVSV.

 

[Stu_22]

So if you have ditched EGR can you chuck away that little electronic module for it

 

[tekdeus]

Is the fuel pressure up vsv still needed when running a AFPR/Walbro with SAFC? Just not sure if the ECU still needs that signal for timing, etc.

 

[jdub]

It's for high temp starts...it's ECU controller when coolant temps are above a certain value. Taking it out can cause hot start issues.
If you remove it, put a vac line between the 2 vac fittings that attach to it.

which I don't need with my upgraded fuel system

And, what makes you think you don't need it?

So if you have ditched EGR can you chuck away that little electronic module for it

You can, but block off the vac line feeding it.

Concerning the EGR...read this...start at post #16:
http://www.supramania.com/forums/showthread.php?t=78780&page=2

 

[tekdeus]

After a lot of searching, I found some small spring clamps. http://smallengines.ca/ecom.asp?pg=products&specific=joonirirk&gotogrp=2021&gotopgnum=1

They are $3.75 each locally here. I would have felt ripped off to spend $100, so I went with zip ties for now. Let me know if you guys find something similar for a more reasonable price, like .99??

 

[SupaMan]

i dont mean to hijack here but Jdub could you tell me where the VSV is your talking about? I think mines going bad, Im getting a hot start problem the car kinda chokes to life sometimes. The problem started about 3 months ago at the drag strip and it does it every so often. I had no idea what could cause it until you just said that and a lightbulb turned on in my head.

 

[jdub]

There's two VSVs attached to the flange connecting the lower/upper intake manifolds...the aft VSV is the EGR...the forward VSV is for the hot start idle up.

Here's how to test it:
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?S=FI&P=116

Check the vac lines 1st before you remove it to make sure it hasn't popped off. An easy way to check (if you have an FPR with a gauge on it) is pull the vac line off the FPR and there should be a FP rise.

 

[92TealSupra]

I use nice metal clamps, it makes everything look very good, if you like have a impressing engine bay. if you choose to move them or take them off you also can reuse them for many other applications. I have had well over 20 psi~
I never blew off vacuum lines, just a inter cooler pipe once.

 

[NashMan]

i used cable tie they failed on me so super gule work on in my case


depends what you are keeping in the car ect you can ditch alot of stuff and make the vac lines simple as pie

Small cable ties
(mine stay on at 30psi)

 

[tekdeus]

Ok, final couple of questions:

- Are the 2 vacuum ports at the top of the throttle body different than the ones after the TB? Last time I looked inside the throttle body, those ports seemed different, being directly next to the throttle plate when closed.

- Should my fuel pressure regulator(AFPR) be running off the top TB port?(the one closer to the rear of the bay)? Or off the intake after the TB?
I am getting rid of the FP up VSV under the intake(never had hot start problems anways).

- I have one vac line connected to the lower port on the thermostat BVSV 23262, but nothing on the upper port. Where is this port supposed to connect to?

Thanks for the help so far guys, I've figured out what I don't need, and will replace the rest of the lines with silicone. Especially after one of the stock lines burst a hole in the hardest-to-reach place under the intake. Argh!

 

[Rennat]

upper port on the coolant/thermostat thing is suppose to go to the charcoal canister. you may not have one..

afpr should be manifold pressure, as it sees boost it rasies the pressure.

 

[jdub]

Not that it's a huge difference, but the bottom fitting on the BVSV goes to the charcoal canister

Rennat is correct on the AFPR.

The vac port on top of the TB have an orifice before the TB plate for a reason. The rear fitting is for the EGR (pre-TB)...it cuts vac off from the EGR modulator at idle, effectively closing the EGR valve so there will be no exhaust gas flow at idle. The forward one is routed to the BVSV, but the diagram shows it on the plenum side of the TB plate closed.

Don't use cheap silicone...they can collapse under vac. I'd use good ole rubber myself