EFE valve noise

[Hardwayjerry7885]

I have an 85 C1500 with a 305. It starts and runs fine, but on cold start up the EFE valve is causing some kind of noise. When I unhook the vacuum line it stops that closes the valve it stops. It sounds like a horrendous valve tick but I don't know whether it is the valves ticking or the EFE valve making this noise. I haven't fooled with chevys much so I don't know whether this is normal or not. It just annoys the crap out of me when I start it up and tick, tick, tick until it warms up and the EFE valve opens.

[bd]

EFE valve is probably worn out, or the butterfly is broken loose.  You should be able to use a 1" heater hose cut to about three feet long as a stethoscope to isolate the general source of the noise (e.g., EFE valve, valve covers, exhaust manifold leak etc.).  You may be able to lubricate the EFE valve with heat riser lube.

[Hardwayjerry7885]

I used hose and figured out sound is in the EFE valve. What could loose making that sound and is there any fix other than replacing it?

[bd]

The most common scenarios are: 1) the valve is worn out, 2) the butterfly plate is broken loose from its shaft, or 3) the valve is warped and the gasket is leaking.  The valve shaft also may be seized, so the butterfly is stuck in a stationary position.  You may have to remove the valve to determine which is the case.  However, if it's not just a blown gasket, you'll probably have to replace the EFE valve.

[VileZambonie]

Wire it open for now until you fix it if you're even going to bother.

[Hardwayjerry7885]

Got around to pulling the exhaust manifold last night and found that the valve had broken loose from the shaft. After a few seconds of quality time with my mig I had the nasty clunk stopped.

[bd]

Glad you were able to salvage it.  Give it a shot or two of heat riser lube or PB Blaster while you're in there.