I have a 93 f250 5.8l and I have the problem with all air blowing through the defrost. Does anyone have a diagram of the HVAC vacuum system?

 

With no vacuum the HVAC system defaults to routing air through the defrost vents.



Check the white vacuum line running to the recirculation actuator. It becomes a huge vacuum leak when it breaks apart by looking at it too long. Yes, it's that brittle.


courtesy of subford

 

OK I got the vacuum stuff figured out and all is good but I'm not getting good enough vacuum to the HVAC control head due to a timing issue. I need a timing spout and I don't have the $ to go to the dealer. Anyone want to work a deal out through PayPal or if ur in the middle Georgia area lemme know. Lol

 

The SPOUT plug is a fancy shorting bar, a short length of wire will work. The base timing should be set to 10 BTDC. Even with the SPOUT out there should be plenty of manifold vacuum to run the HVAC.

All Ford vehicles of this vintage use a SPOUT plug, call a few salvage yards, I'm sure you can pick one up for almost nothing.

 

I found one today actually. Thanks alot. And if I crank the truck up and let it warm up it eventually goes to whatever setting I have it on. I plugged the spout up and it really mad no difference but I did notice that the distributor point and the point on the motor do not line up so I'm thinking its off by a tooth. So I have a project ahead of me next weekend. Lol

 

Not sure what you are saying here. With the SPOUT in place the computer controls the timing.

 

I plugged the spout in where it goes and nothing changed. But I looked at the distributor and it has an arrow on it and right on the motor next to the distributor there is another arrow and neither one arrow points at each other and I'm sure they're supposed too. Right?

 

No idea what you are referring to. Perhaps a previous owner made some marks? What does the timing light show?

 

Well that is the project for next weekend I was referring too. The previous owner didn't make any marks its like the arrows were made at the factory or something. The truck is original it only has 102xxx miles on it and I bought it from the original owner. I'm gonna check it out tho and if I get stuck I'll hit u up but if not then I'll keep u posted. Thanks

 

You'll have to take a picture or something. I've never seen marks like that on any ford distributor. It doesn't really matter if the marks line up. You can orient the distributor however you want, I would recommend leaving it where it is unless it's hitting something. The only thing that matters is the actual ignition timing with SPOUT removed.

 

I will send a pic tomorrow of it. But I'm gonna check the timing next weekend. I do know its got to b off a little cuz it does spark knock some.

 

Timing light will tell the story.