Hooking up a carburetor

||This is regarding a 1984 Ford F250 2WD, with a 460 CI engine. ||I uninstalled an aftermarket holley fuel injection and am trying to install ||the original carburetor, but what do I connect where? The truck had the EFI ||on it for several years and was installed by someone else, so its not like I ||can even attempt to remember how it was connected. || || ||See the numbered diagram at: || ||

|| || ||Numbers 4 and 5 are for the fuel intake and outlet but its numbers 1 to 3 ||that I am totally bewildered about.

#4 is the fuel inlet. #5 is the hot air tube connection. It needs a steel tube coming up from the exhaust manifold.

||#1 is some kind of diaphragm thing on ||the back of the intake manifold

EGR valve, needs vacuum but maybe not straight manifold vacuum. You DO have a manual of some kind, right?

|| do I need to connect a tube to number 2 or 3 maybe?

#2 is the filtered air intake for the choke tube. You should have two parallel steel tubes coming out of the right exhaust manifold. One goes to the choke assembly (#3), the other goes to #2

#3 is probably the ported vacuum for the distributor vacuum advance. I assume that arrow is pointing to a 1/8 NPT female threded hole in the metering block between the fuel bowl and the carb body.

Texas Parts Guy

It would be run off a modulator of some type. You probably wouldn't want it off a straight vac line, as it would run bad when cold. There should be no EGR when cold, or at idle. The problem in his case, the

84 was probably a feedback carb setup with a puter. You had input sensors to tell the puter what to do. IE: when cold, a temp sensor should tell the puter to not enable EGR vacuum when cold. I'm trying to remember what the pre-puter cars used to operate EGR vacuum...I guess a plain ole vacuum modulator...I can't remember what they did to disable EGR for cold operation in the old days before puters...Maybe a modulator with an exernal temp sensor involved?? My truck doesn't even have an EGR valve...The 84 really needs the puter operating, and all sensors involved to be like original. And probably to pass smog tests too, if thats an issue..Yep, a manual would be real handy...

He can ID it pretty easy when running... If it's ported, there will be no or little vacuum at idle, but will pick up with throttle. An unmetered port will have much more vacuum at idle. MK

No computer on the '84. It had the EEC-IV ignition.

Spdloader

That would be a Ported vacuum switch. Theremopill valve that screwed into the water jacket, with two hose connections: Vaccum port, and EGR valve. When cold, ports were shut and EGR saw no vacuum. When warm, port is open and you have EGR.

Personally, if it were mine, I'd try it with EGR disconnected. If it runs fine, and you don't need it working to pass inspection, then leave it disconnected. This is assuming it is closed with no vacuum present.

Texas Parts Guy