New manifold gasket

[FreshZ]

ok. I changed the manifold gasket on the 280z and buttoned everything up. But now I'm getting a hissing sound coming from what appears to be an area near injector #5.

I double checked all the bolt connections, gasket and surrounding areas prior to installation. I started the car up and right away I hear hissing (vacuum leak sound) from injector 5 area. WTH can this be? Anyone else experience this? can the injectors get loose from the intake manifold removal process?

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[Zed Head]

The FPR can make a hissing noise.  Did you use new seals and insulators on the injectors, small and large (the round rubber pieces)?  Are you using the two-screw clamps?  They actually put some pressure on the lower seal by tightening on the top, big, insulator.

Does it run like there's a vacuum leak?

[FreshZ]

I didn't remove the injectors when I removed the intake manifold. I kept everything intact as possible. I haven't taken it out of the garage since the manifolds were reinstalled. but it starts and idles fine. just has a hissing sound.

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[Zed Head]

Run the pump without the engine running and see if you can hear the hiss.  Squirt some carb cleaner at the leak area and see if the sound changes.  Grab the injector by hand and press it down and see if the sound changes.  Pull the injector up and see if the sound changes.  Lots of ways to learn more.  Not uncommon for the seals to harden over time, then some bumping and moving can create a leak.

Would have been super easy to replace the seals while the manifold was off.  Still not that difficult.  And they're cheap.  I have a vague memory of writing this before.

[FreshZ]

good idea. I'll try that pump without starting and report back with my findings. As for the injector seals, I changed those all out a while ago when I put in replacement injectors.

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[FreshZ]

I just found the intake hissing leak. An egr delete was added, but has a bad seal. a little JBWeld should fix this. Crisis averted! I did in fact install all of the gaskets and head bolts properly....WhooHoo!!

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[rcb280z]

2 hours ago, FreshZ said:

An egr delete was added

How was this done? Don't remember what year 280 you have but here in CA you'll fail an emissions test with the EGR disabled. They check it on the '76 and on models. They checked function on mine.

Edited January 4, 2017 by rcb280z

[FreshZ]

I have a '75. It started with a piece of printer paper to get initial shape, then moved to cardboard to get things tighter to the shape it should be, then finally to some aluminum flat stock and some gasket maker.

left the studs in place in case the egr needs to be reinstalled at a later date.

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[FreshZ]

How was this done? Don't remember what year 280 you have but here in CA you'll fail an emissions test with the EGR disabled. They check it on the '76 and on models. They checked function on mine.

I have noticed that it is hard to find a running '75 for sale in California.

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[rcb280z]

Yeah if you have a 75 you are safe for now, so to speak.

[FreshZ]

are there model year exempt changes in the works?

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[rcb280z]

3 hours ago, FreshZ said:

are there model year exempt changes in the works?

NOPE! And we have Schwarzenegger to thank for that when he was State Governor. Did away with the "Roll-over"  I believe it was called. The '76 and '77 models were next to go to smog exempt until he stopped it.