'91 Vacuum hoses on rear of the Intake Plenim

[Tony H]

I did an Intake Manifold gasket yesterday.
The only issue I have is that When I started the car I had a Vacuum leak because one of the nipples is not covered on the Plenim, close to the Firewall on the drivers side.

I marked everything and nothing is left hanging . There was a small piece of rubber that was left on the one open nipple. Please can someone tell me if out of the seven nipples on the back, did one just have a rubber Cap on it and not a hose going to somewhere?

I temperarily put a hose with a screw in it to cap it off and everything functions perfectly, runs smooth. My guess and hope is that it just had a Rubber Cap on it and it just broke away. I have 6 hoses going to it now. Is that all there is?

 

[MrShorty]

Depending on options, it is quite common to have one or more of those nipples on the intake plenum simply capped off. If all vacuum controlled accessories are accounted for (on a '91 that would be: fuel pressure regulator, cruise control, brake booster, PCV, vacuum reservoir, air filter housing, ami I missing anything?), then cap the remaining ports off.

 

[Tony H]

I labeled the heck out of everything and there's no spare parts that's why when I fired it up and I heard the leak my stomach dropped.

I was sifting around the garage and the driveway for the top end of the rubber cap to satify me but.no go.
Everything seems to be functioning so I'll look for a better Cap then the ole screw in the gas line trick and let it go at that.
The PCV valve is a shorty hose that goes directly from the PCV to the bottom of the Plenim.

That wasn't one of the more fun jobs , Way too much dissassembly to get at the dopey intake gasket.
The only nice thing is that After 230K miles, I looked under the valve covers to be absolutely amazed at how clean the heads were. No gack at all on the Valve covers or the Rocker part of the Heads. so I know the engine isn't all crudded up.

 

[Rhett]

The only nice thing is that After 230K miles, I looked under the valve covers to be absolutely amazed at how clean the heads were. No gack at all on the Valve covers or the Rocker part of the Heads. so I know the engine isn't all crudded up.

Lucky you, mine was crudded up at 80,000. Now, where can you buy some little caps to fit over the vac ports?

 

[Tony H]

I'm a firm believer in 3000 mile oil changes but honestly, out of all my cars this is absolutely the cleanest under the Valve Covers. Don't ask me why. In fact the guy I bought it from ( 3 years ago) was one of those 'don't fix it until it breaks' kinda guys so I expected to be taking a spackle knife to the valve area..

Rubber caps...Beats me as to where to get them.

 

[410Fortune]

any auto parts store has vacuum caps, sometimes in the HELP! section.

 

[Tony H]

Good. Thanks. I never remember seeing them there but I never needed them.

Thanks again.