1986 Sierra Classic Wont Idle!!

[HotRodPC]

The egr remains on the intake. It has two bolts that hold it in place right under the carb. There are definitely no ports or anything on the carb that isn't hooked up. That's why I was interested in where the egr port would go to on the carb because every port on carb is hooked up to something so where could it have went originally? Understand its not really important but anything small I can do to improve it is a plus.

So have someone on the gas just enough to keep it running and spray base of carb? Will it idle higher or what?

The EGR would have originally went into a TVS (Temperature Vacuum Switch) usually in the thermostat housing. This keeps the EGR from not being able to function on a cold motor. The other end of the TVS would have been connected to a Vacuum T or or port in the intake manifold.

 

[chengny]

Lars says:

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But I thought air leakage under the throttle plates generally causes an increased idle - not a depressed idle condition? Unless I'm reading this wrong:

Once warm it will not idle. Have tried backing in and out idle adjustment screw on drivers side (after it was at operating temp) but still wouldn't idle. BARELY have to have foot on gas though..



his engine won't stay running - unless he cheats by using the accelerator?

 

[domino33]

jerry- thanks for some input. My first post stated that i was able to get truck to idle (high idle) while choke was operating- this is correct, as i screwed the choke idle adjustment screw in very far..maybe too far. as i understand, the further the screw goes in-the higher the idle. I have since adjusted it lower, but still able to idle.

after it warmed up and choke was fully open, truck died. So at first, like i said, I adjusted regular idle screw in and out just basically trial and error seeing if it would idle, and nothing. it wasnt until Skweegle89 suggested to just keep turning screw in further until it idle, which proved to work.

So furthermore the excerpt you posted remains true, as those are the symptoms i am experiencing. The truck simply dies when the idle screws are in any "correct" position.

I do have a question though. The new gasket came, one side is textured and the other smoother. which side points where?

 

[chengny]

It probably doesn't matter if both surfaces (carb/manifold) are smooth.

But on any component that may have to come off in the future, I always use a tiny bit of adhesive (or silicone)to bond the gasket to the removable part. The other face of the gasket (the one that goes against the mounting surface of the stationary component) gets a good coat of never-seize.

That way, when the time comes to remove it, the gasket will stay with the part and the other side wont tear as it is pulled off. Carburetor gaskets have a tendency to break up upon removal if you just make the joint up dry.

 

[domino33]

Okay, thanks for the tip. just got the carby off, gonna run to the store for some type of sealant. and you're right better safe then sorry.

 

[Skweegle89]

I use blue RTV, but about any of it will work.


Sent from an old rotary telephone.