Strange Issue and hissing noise. 1985 gmc sierra K1500 4x4. automatic 700r4.

[Irish_Alley]

it aint nothing just make sure your distributor goes in the same way it came out(timing) and when you go to put in your new intake gasket set just throw away those rubber ends they say to use with it. never had one not leak with the rubber. used rtv gasket maker and clean both surfaces good.  never had one leak with the rtv

[jason]

So how can you be sure you have the correct gaskets? I ordered the kit online and specified the kit using my carb number 17085248.

The truck only has 170,000 km on it... and I checked the throttle shafts and they feel pretty tight; not much play in them.

Why would the squealing be coming from the main nozzle, bleed area?

What does the bleed do?

I've got it prepped with a razor blade and cleaned with brake cleaner.  Just have to wet sand it and complete the cleaning with the acetone and it should be on there this week.

[bd]

So how can you be sure you have the correct gaskets? I ordered the kit online and specified the kit using my carb number 17085248....

...Why would the squealing be coming from the main nozzle, bleed area?

What does the bleed do?

I've got it prepped with a razor blade and cleaned with brake cleaner.  Just have to wet sand it and complete the cleaning with the acetone and it should be on there this week.

Some carb kits come with multiple bowl gaskets, because the kits service a span of model years.  Typically, when there's more than one gasket for a particular purpose in the carburetor, you compare the new gaskets to the old gaskets and choose accordingly.  The shape of the bowl cover varies in the cluster area between some carburetor versions - some are squared, some are rounded; other variations may exist, as well.  If the wrong bowl gasket is used or if the bowl cover is warped and not sealing, air/fuel leaks can result.  Occasionally, they'll squeal or whistle. 

The main air bleeds introduce air into the fuel channel prior to discharging from the main nozzles.  They affect tip-in sensitivity and help tailor fuel delivery.

Sounds like you're well on your way to having it completed.

[jason]

Thanks for the tips.  I have had the truck running for a few days now.  I took it to a shop and they said "it idles really high".. that's because the intake wasn't installed correctly. 

I got the intake installed correctly and used the proper torquing sequence and it fired right up without even pumping the gas pedal.

After getting it warmed up it would go down to 300 rpm and stall...
The shop was trying to get the rpms down from the vacuum leak and reduced base idle to "0" with the screw.  I got the base idle adjusted and it just purrs. 

Life's good, the truck runs.

Thanks a lot for your advice and tips!  It helped get my 4x4 back on the road and running better than it has in the last 15 years for sure!

[bd]

Very glad to hear you got it fixed!!

[454Man]

X2

What's under the hood??? If you have to ask maybe we shouldn't race...