1981 egr hose

[sammy81]

I have a stock 1981 vette. The previous owner had the
egr valve vacuum hose attached at the egr valve but
unattached at the other end. I can't find the location
to attach the other end of the hose. The hose is
about 12" long and has a orange stripe on it. Any clues
on where it goes to? Any pictures would also help.
New vette owner and avg. mechincal skills.
Thanks,
Sammy

[mik13usa]

Sammy,
you are probably going to have to remove the air cleaner assembly and do a little detective work. I owned a highly modified '80 that started out similar to your 81. If I remember there is only one area that the hose attaches to on the carburetor, I think it is on the throttle body (base plate of the carb) on the passengers side. If the hose has been disconnected for a while you might want to check the PCV for clogging and carbon (crud) buildup. It is pretty easy to clean with a stiff brush and any good brand carb cleaner! Good luck.
Mik

[rjm65]

From memory here.... don't recall just where the vacuum is drawn off the carb, but from there it goes to a thermal vacuum switch on the thermostat housing, then to an electrical vacuum switch thats to one side of the EGR valve (bolts to the intake), then to the EGR. The idea being that vacuum is only provided above certain temps, and also controlled by the ECM.

Originally Posted by sammy81

I have a stock 1981 vette. The previous owner had the
egr valve vacuum hose attached at the egr valve but
unattached at the other end. I can't find the location
to attach the other end of the hose. The hose is
about 12" long and has a orange stripe on it. Any clues
on where it goes to? Any pictures would also help.
New vette owner and avg. mechincal skills.
Thanks,
Sammy

[mga]

right behind the EGR valve is a solenoid. at the cery bottom is 2 connectors for vacuum hoses. the hose you are asking about loops to the bottom most vacuum port at this solenoid.

[garrickh]

I have been struggling to piece together the routing of the enissions and vacuum hoses on my L81, so I feel your pain.

If you have the stock hood, there is a diagram which gives you a very rough idea of where the hoses should be routed. Another big help was purchase of a shop manual (used, $20, ebay)

There are actually four ports (behind the EGR) on the EGR solenoids mounted to firewall, passengers side. I'm also assuming you have the Rochester Q-Jet (w/ throttle position sensor mystery machine) carb sitting on top.

The underhood diagram does not seem to show exactly which port is where, but following it in order.
-Top port routes to port at top rear of carb.
-Next port down routes to a "y" connector.
-Next port down routes to EGR.
-Bottom port routes to other half of "y" connector. Route "y" connector to vac port at the lower front, passenger-side of carb.

The previous post indicated the bottom port routes to the EGR, but the size of the EGR port and the port that I indicated look identical. (Let me know if this is incorrect.)

I know the diagram seemed to have a mistake in the routing on the vac hoses for the dampers on the air cleaner assembly, so anything is possible. It may take some guess work.

I have a question about the "thingie" in FRONT of the EGR. There are two ports and two bolts which mount it into the intake. I removed it from the intake and it looks very much like a miniature block heater. But it definately is not. I have no idea what is to be routed to this. I have no guesses as to what it does. It is not mentioned in the shop manual or the diagram. Can anyone help?

[rjm65]

In front of the EGR? Are you referring to the vacuum routing or physically directly in front?

Originally Posted by garrickh

I have a question about the "thingie" in FRONT of the EGR. There are two ports and two bolts which mount it into the intake. I removed it from the intake and it looks very much like a miniature block heater. But it definately is not. I have no idea what is to be routed to this. I have no guesses as to what it does. It is not mentioned in the shop manual or the diagram. Can anyone help?

[garrickh]

Originally Posted by rjm65

In front of the EGR? Are you referring to the vacuum routing or physically directly in front?

Sorry....Said "thingie" is actually mounted onto the intake, directly forward of where the EGR is mounted. The two are a centimeter or so apart.

I loosened the two bolts which hold it in place and it was like an iceberg...most of it was actually inside the intake.

Very simple piece, though. About five inches in overall length. There are two ports on it. They loop to each other. That's it.

(I'll take a pic and upload to the web tonight. I realize this may be a bad description.)

I am new to the forum and I look forward to participating and contributing as much as I know. Thanks.

[garrickh]

Originally Posted by garrickh

I
The underhood diagram does not seem to show exactly which port is where, but following it in order.
-Top port routes to port at top rear of carb.
-Next port down routes to a "y" connector.
-Next port down routes to EGR.
-Bottom port routes to other half of "y" connector. Route "y" connector to vac port at the lower front, passenger-side of carb.

I checked my Assembly Manual and it has them in this order...

-Top port routes to port at top rear of carb.
-Next port down routes to a "y" connector.
-Next port down routes to other half of "y" connector. Route "y" connector to vac port at the lower front, passenger-side of carb. (Port directs from carb at an 45-degree angle.)
-Bottom port routes to EGR. (I stand corrected.)

-garrickh