Accessing the vacuum lines under intake plenum. (1 Viewer)

[Rusty Cruiser]

For those who have replaced the vacuum lines under the intake plenum...can they all be done with just the throttle body removed or is removing the top of the plenum necessary?
Started replacing lines today and just realized how many are not easy to get to! Thanks!

 

[BILT4ME]

For those who have replaced the vacuum lines under the intake plenum...can they all be done with just the throttle body removed or is removing the top of the plenum necessary?
Started replacing lines today and just realized how many are not easy to get to! Thanks!

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Most on here remove the upper half of the intake plenum.

This also allows access to the injectors if you decide you want to do something at that time.

 

[surfpig]

I've been told that you "can." I have really small hands, and I "can't." And I've tried a couple of times. Blood loss was somewhat
significant.

 

[Fj80oregon]

Why are you replacing them? I asked because it’s probably time to do other things if you’re worried about crusty vacuum lines. Pull the upper plenum, clean it and the throttle body. Clean the metal passages thru the plenum. Test your solenoids and egr valve, realize you mine as well have the fuel injectors serviced. Then be happy you did a proper service and it was well worth the effort.

 

[ZackR]

As long as you have some long socket extensions its not hard to pull the upper intake. Once it's off you'll see how easy it is to access everything.

PHH and small coolant hoses
fuel filter
Wiring harness
Vacuum lines
Fuel Injectors

 

[Aloha Jen]

It’s considerably easier to change out all the lines with it off. I just helped out swapping all the lines on our ‘94 80. Buy a bunch of the OEM vacuum line segments, it’s good stuff and relatively inexpensive if I remember correctly. Take an old one off, cut the new one to same length, and put back in same location. Mine were all hard as a rock. Should also use some compressed air to blow out the internal lines through the manifold.

 

[Rusty Cruiser]

Why are you replacing them? I asked because it’s probably time to do other things if you’re worried about crusty vacuum lines. Pull the upper plenum, clean it and the throttle body. Clean the metal passages thru the plenum. Test your solenoids and egr valve, realize you mine as well have the fuel injectors serviced. Then be happy you did a proper service and it was well worth the effort.

When the engine is warm and I have to idle for an extended period of time (school pickup line) idle speed gets a little low. Makes me think I have a small vacuum leak.

 

[Rusty Cruiser]

It’s considerably easier to change out all the lines with it off. I just helped out swapping all the lines on our ‘94 80. Buy a bunch of the OEM vacuum line segments, it’s good stuff and relatively inexpensive if I remember correctly. Take an old one off, cut the new one to same length, and put back in same location. Mine were all hard as a rock. Should also use some compressed air to blow out the internal lines through the manifold.
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Thanks Jenny, it def looks much easier to do with it off! I did get a few sections of the factory hose from partsouq already.

 

[Rusty Cruiser]

As long as you have some long socket extensions its not hard to pull the upper intake. Once it's off you'll see how easy it is to access everything.

PHH and small coolant hoses
fuel filter
Wiring harness
Vacuum lines
Fuel Injectors

Thanks Zach, now I know what else to have ready once I’m ready to pull it off.

 

[Malleus]

FWIW, you'll need one 1-m length (90999-92004) to replace the entire vacuum lines system. No need to buy short lengths; it's all the same hose.

 

[Fosters]

A good thing to do is smoke machine your intake…it’ll identify any and all vac leaks…machines are cheap enough on Amazon