Good morning gentlemen. I have three questions regarding vacuum lines on my 87 GT and I was in hopes you guys could answer.

Does anyone know the diameter of the vacuum lines?
Is there any reason to not cap off the lines under the UIM?
Lastly, is the gasket under the UIM reuseable?

I'm not planning on buying a kit as the 2.8 will eventually be pulled.

Thanks

[This message has been edited by Slow6 (edited 07-24-2013).]

quote Originally posted by Slow6: Is there any reason to not cap off the lines under the UIM?

The engine will not run if you cap off the lines under the manifold....or am I misreading your question?

quote Originally posted by Gall757: The engine will not run if you cap off the lines under the manifold....or am I misreading your question?

Nope that was one of my questions. Thanks for the response. I figured it would be fine to block those off and run the Old ones going to them to another part of the intake manifold, since they appear to only be sources of vacuum. Would make things easier if I have to do this again. I'm probably going to run everything to a vacuum block to simplify things.


Anyone answer either of my other 2? Diameter of the vac hoses and if the UIM gasket is reusable(if there is one)

[This message has been edited by Slow6 (edited 07-24-2013).]

I don't know about the diameter of the lines, but your gaskets may be reusable if they're only stuck to one half of the mating parts. Once the gaskets are torn though, you'll get air leakage and run lean with a high idle. They only way to know for sure is to disassemble it and see how it goes. In my experience, the gaskets always get stuck to both parts and are ruined.

As for which vacuum lines are important, here's a schematic that Buddycraigg (a PFF member) did up a while back:



Things like cruise control can be capped off without any real problems but the rest are needed.

Thanks for the diagram. I'm planning on doing a little write up with a few pics. Something I enjoy doing with the car communities I'm a part of. Hope no one minds.

[This message has been edited by Slow6 (edited 07-24-2013).]

Buy a sheet of gasket paper, you can make about 4 sets of uppers for about $5. all you need is a sharp "Hole punch" and a razor blade. you should be able to just put a Very light coat of grease on the gaskets and re-use them indefinitely. I used steel brake line for the vacuum lines.

and if you have any cracks or holes in your lines.. wiper washer fluid hoses and zip ties work to fix those.. they fit snug and perfect surprisingly ...

food for thought

Conner

quote Originally posted by Lou6t4gto: Buy a sheet of gasket paper, you can make about 4 sets of uppers for about $5. all you need is a sharp "Hole punch" and a razor blade. you should be able to just put a Very light coat of grease on the gaskets and re-use them indefinitely. I used steel brake line for the vacuum lines.

Didn't even think of that. Oh well already purchased a gasket kit from the parts store. I'll just use that, but thanks for the input.

quote Originally posted by gmctyphoon1992: and if you have any cracks or holes in your lines.. wiper washer fluid hoses and zip ties work to fix those.. they fit snug and perfect surprisingly ... food for thought Conner

Funny you mention that I did that very thing on my GTP before I went turbo and upgraded to silicon vacuum lines.

As you can see below you do not need to stay with those fragile plastic lines.

------------------

trueleo.com
RSpiderII@aol.com

That's a nice looking engine Mr. T

Arn

I only have (I guess) 3 vacuum lines.

One goes from the MAP to a T to the FPR

One is fat plastic tube from the rear valve cover to underneath the UIM for the PCV

And the other kind of counts, but the metal line from the front valve cover to the rubber intake tube.

You can cap all the others no problem, just leave your vapor canister hooked up or delete it and route the metal line right to the air cleaner housing (used a brass fitting and rubber fuel hose for this). If you leave it hooked up you should plug the little lines on top.

My EGR is deleted too so those lines are gone.

The line from MAP to T to FPR can be made from brake line, any size line that fits will work it is solely for vacuum which is an independent property from line size. So no matter what line size you use it will register the same pressure at either the MAP or at the FPR. My engine bay is much simpler now and I don't have to worry about as many vacuum leaks

Also you can just use RTV on the UIM it will work fine. Might not last forever but that does not seem to be a concern. I have seen blue used. Or buy some gasket material and make some gasket by tracing the old ones. Cost a couple bucks.

Zach

[This message has been edited by zkhennings (edited 07-26-2013).]

Thankyou to all that have responded. I'm just about finished up. Did the valve cover gaskets while I was at it and now I'm down to putting the upper plenum back on. Quick question. Does anyone know what the hard metal vacuum line off the firewall goes to? It's not listed on my sticker. Goes from driver to passenger side and is not currently hooked up.

Thanks

About 5/8ths diameter? That one goes nowhere. A recall on the PCV system left it unconnected. There is also a small dia. line that is an air supply for the EGR solenoid which is sometimes disconnected.

[This message has been edited by Gall757 (edited 07-26-2013).]

quote Originally posted by Arns85GT: That's a nice looking engine Mr. T Arn

Thanks, it's maxed-out with internal mods, forged piston, wild cam, etc, etc. It's also in the car now and the car is about to get new paint job.

Spent the better part of the day removing the plenum, installing valve cover gaskets, and fixing the vacuum line hack job. Got most of the way through before I had to call it quits. Today I was reminded of how relaxing listening to music and turning wrenches can be.

What I started with



Started with the removing the air intake assembly:


Unbolted the TB:



Unlike the GP the EGR is connected at the bottom of the UIM:


Upper Plenum removed:


TB and upper plenum removed:


Fuel Line removed from rail. Nice to not have to use a fuel removal tool for once:


Fuel rail and full plenum removed:


Valve cover removed, gasket replaced(did this for both sides), and reinstalled:



Plenum reinstalled:


Fuel rail reinstalled:


Vacuum lines starting to be run (Map sensor/FPR/EGR)-TB coolant lines reinstalled



Time to scrap:



Plenum Torqued:
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TB bolted more vac lines ran:


Still need to route a few more vac, reinstall the throttle cable, and reinstall the air intake ducting.

Unless I missed it some where here.
There is a larger vac hose to the brake booster line at the fire wall to the upper intake.
You will need that for sure..........

quote Originally posted by mcguiver3: Unless I missed it some where here. There is a larger vac hose to the brake booster line at the fire wall to the upper intake. You will need that for sure..........

That's what that line is! I couldn't figure out for the life of me what that went to. I figured it was important since the hard plastic line snaked through the back of the manifold and was bolted to the plenum. Lol

Hello,

I´m new in this forum and I have a question regarding a mystery vacuum line
which is routed from intake duct to UIM on my 2.8 V6 stock engine.

See the small hose on the following picture:


I think this is not the OEM setup (perhaps a modification form the previous owner)!?
Does anyone know where this vaccum line from the UIM is connected on a stock 2.8 V6 engine?

BTW, this is my new car, a 87´Fiero (has been imported from California to Austria by the previous owner):


@Slow6
I think to the air intake duct only the PCV hose is connected.
(PCV hose from the valve cover on the firewall side)

Thanks

[This message has been edited by Moar (edited 05-09-2015).]

Moar: That line connected between the air intake snorkle and the manifold would only provide for an open vacuum and would probably cause a very high idle. See Bloozberry's posting of BuddyCraigg's vacuum line diagram above. That port is the bright green line.

Now, for cutting gaskets. Without benefit of a hole punch of the correct diameter, just carry a ball bearing in your tool box. A very useful tool when you need to cut gasket holes of any size. A half-inch diameter and a quarter-inch ball bearing will serve most automotive purposes.

Using Slow6's series of pictures, picture number 17 where the upper intake is upside down and clean. First, cut a piece of gasket material to cover the area of the required gasket. Next, lay the gasket material on the piece that DOES NOT have the threads. Press the ball bearing into one of the bolt holes using your thumb, enough to make a dimple in the gasket. Leaving the ball bearing sitting in the dimple, tap on the bearing with a hammer. It will cut a hole in the gasket to the perfect size of the bolt hole. Now put a bolt through it to hold it in place and do the same with a second bolt hole, preferably on the opposite end of the piece then place a bolt through it. Finish off with the rest of the bolt holes.

Next, to make the gasket the same shape as the part, lightly tap along all the edges with a hammer and it will cut to the shape of the piece.

To repair the hard plastic vacuum lines on a Fiero, find the crack or break, slide an appropriate size piece of electrical heat shrink tubing over the line and shrink the tubing down to hold the hard plastic. Using black heat shrink, it becomes almost invisible on the hard plastic line.

That is the green line in the diagram pictured above.

Slow6: Look at Moar's picture. He answered your question about the hole in the back of the air intake tube, both in text and the picture. There was a metal tube that extends from that hole and goes over to the center of the valve cover. It's part of the crankcase rebreather system. You can see the tube running from that port, turning to cross behind the throttle cable cam and heading toward the valve cover. Don't run or drive the car without that tube in place. Oil spray coming from the open port in the valve cover can contgact the exhaust manifold and ignite.

Hi,

thank you for quick replies.

Now I understand the vacuum diagram from BuddyCraigg.
Obviously on a stock engine this vacuum line (green line in diagram) is just for the cruise control.

I´ll plug it on the UIM like Slow6 did it (see red hose plug on last picture sent by Slow6).
I don´t need cruise control on a sports car, because a cc-unit has too much weight
and needs too much space for my taste.

The hole on the intake duct I´ll seal with black PU-sealant.
Then the idle speed should drop to a "normal" speed again.
(actually my Fiero idles at 1800 rpm!)

@ fierofool:
Thank you for the DIY-gasket how-to!
But isn´t there any elastomer gasket kit available for the Fiero UIM?
(I´ll remove the UIM more often next months and elastomer gaskets will last longer)

I don't know if they're available in Austria, but I've always purchased FelPro gasket set MS 93020 . MS stands for Manifold Set. I don't think you can purchase gaskets for any individual part of the manifolds. The upper gasket can be reused if it's only been on the engine for short periods of time. Just as long as it doesn't get torn when removing the upper plenum. I've actually removed one upper plenum and put it back on when it had what I believe to be the original factory gasket. Guess I was just lucky in that respect.

quote [B]Originally posted by The hole on the intake duct I´ll seal with black PU-sealant. Then the idle speed should drop to a "normal" speed again. (actually my Fiero idles at 1800 rpm!)

The hole in the intake tube should have a hard black pipe coming from the front vavle cover.

@fierofool: Nice tips with the ball bearings and using them to cut holes for gaskets! I LOVE to learn little tricks like that that I can use! +1 for you!

Yes, the FelPro gaskets are very good quality.

I can confirm this because I have already bought a valve cover gasket set from
FelPro and they are quite durable elastomer gaskets.

I think OEM gaskets are not as good as FelPro gaskets.
I have already removed the UIM from my 3.4PR engine (which I´ve bought for the engine swap).
The OEM UIM gasket was very porous and broke apart in many small parts.

BTW, I always order parts directly from USA for my Fiero and let them ship to
my tax-free forwarding address in Delaware. (therefore I can get the same parts like you )
Also for my other cars (Miata, and Jag) I never buy parts in my country, because auto parts are
very EXPENSIVE in Austria (especially parts for US-cars )!