I have a 1981 Class C motorhome based on an E350, with a 460W and a Holley carb. The EGR system has been disabled, and it the remaining vacuum connections are only partially intact.

I've read nearly every post here regarding EGR, bought a Haynes book and searched the Internet, and found nothing very helpful for my setup.

I've connected the EGR directly to the vacuum advance port on the carb. When I open the throttle the EGR valve opens and the engine begins to stumble. I take this to mean that the valve is working and the ports are clear enough to allow the gasses through.

The only label on the engine shows general tune up info, but nothing about vacuum. There are no other labels anywhere in the engine compartment or under the hood.


I see the usual vacuum valve on the thermostat housing but there's also a modulator looking thing and what looks like an electric vacuum valve mounted to the RH valve cover. I've read a bit about the solinoid valve but don't know how it's supposed to be connected into the circuit.




Does anyone know how this stuff should be connected to get proper EGR function?

Thanks!

 

I spent another several hours yesterday searching the Internet for anything that shows the EGR vacuum connections for an '81 E350 with a 460 and managed to find nothing useful again. So today I decided to give Alldata a try. Wouldn't you know it... They only go back to 1982.

Does anyone have any idea how the EGR vacuum lines are supposed to be connected on this thing?

Thanks!

 

Since nobody seems to have a vacuum diagram for the '81 EGR setup, I decided to go with what I know...

I added a T connecter to the ported vacuum off the carb and routed a new hose to the vacuum control valve on the thermostat housing. From the other connection on the vcv I ran through a short hose to a vacuum restrictor (Dorman # 47311 available at O'Reillys) then to the EGR valve.

The restrictor could restrict a little more than it does, but I'm gonna run it like this for a while and see how it goes. If I decide it needs more restriction, I can always epoxy the end shut then drill a smaller hole through the epoxy than the original was.

I need to replace the EGR valve gasket now and bump the timing a bit, then I think I have it working pretty close to the way it should.

Thanks anyway.

 

Maybe a Ford dealer would have the routing diagram or somebody else with a similar motor home?

 

I called the local dealers... They're "happy" to take a look at it for their normal shop rates.

The only folks I know around here with motorhomes in the same year range have Dodges or GM's.

I kinow the way I have it is typical for earlier models. The only thing I might look into is the electric solinoid valve. If it's connected to the shifter, or is designed to actuate when the engine is under load I may put it back in the circuit. I can mess with that next month when I'm not under a time crunch to get it running reasonably well.

Thanks again!

 

I know this post is long dead but I figured I'd post here too just in case anyone ends up here trying to ID this part like I did. It's an EGR Venturi Vacuum Amplifier and it is abbreviate VVA in the emissions diagrams.