Vacuum heater control issue

[pyro]

Not sure where my problem is stemming from. I did an engine swap (stayed w 258) and am hooking my heater controls back up. It seems like the vacuum is too weak to pull in the control arms on the actuators. I tried both the vacuum port on the top rear of the manifold and the port by the brake booster port and no change. The lines are all routed correctly, and I can feel the vacuum when I pull the hose off of the actuator by the heat outlet. Any ideas?

If I manually pull the arms the system switches between heat and defrost, just not by vacuum alone. It worked fine on my old engine, I just don't remember where exactly I was getting my vacuum from. Here's some pics of the setup:
The port at the back of the manifold (currently capped)


Port near the brake booster (where it is now)


Goes from that port through the vacuum canister


Routes into the selector correctly

[carnuck]

With the motor running, is there vacuum from the hose where the red arrow in the last pic is pointing? (check with a gauge is best) If there is, get a cheap vacuum tee and take the hoses off and join those 3 hoses together with the tee to get defrost and heat at the same time.

[rocklaurence]

Any chance your Vac can is cracked and leaking or cracked fitting at the can? You didnt change anything under the dash with the motor swap --right?

[pyro]

Yeah I've got vacuum all the way to the vacuum door controllers. I didn't think to check the canister, however it worked fine before I removed it and I never dropped it etc. It was a direct engine swap, no other changes. I'm going to try tomorrow and see if I can rig up the vac line directly and bypass the canister. I don't have a gauge...I should pick one up though. What should I be reading on a gauge?

[Mdcptman]

Get a hand vacuum pump w a guage. Its a useful tool to have. You can hook it up to your manifold vacuum source with motor running and see how much you have, then connect it to the vacuum motor and pump it till it moves all the way. That tells you how much you need. If you have enough at the manifold, then you have a leak somewhere. Good luck!

[serehill]

Get a hand vacuum pump w a guage. Its a useful tool to have. You can hook it up to your manifold vacuum source with motor running and see how much you have, then connect it to the vacuum motor and pump it till it moves all the way. That tells you how much you need. If you have enough at the manifold, then you have a leak somewhere. Good luck!

I ran into this long ago where the fitting in the intake was stopped up. Not completely but enough to keep it from working. Mine is also connected @ the egr on mine.

No magic just facts this unit will test all of the entire system leaks stopped up system, system function & motors. No guess work you can tell how much vacuum it has, how much it needs test circuits & that's only one of a ton of things you can do besides the easiest brake bleeding there is. Just like Todd said.
http://www.toolplanet.com/product/Brake ... aQod7SgIEw.




THIS

[Tatsadasayago]

I would suggest you look at, and listen to the heater controller for vacuum leaks as well. I've had them leak (silently) enough to prevent the actuators from moving yet have 20-22" of vacuum at the source port. A decent test is to spray some WD-40 around the switch while the engine is running and listen for an actuator to move briefly.
This works well for leak testing lines, fittings and the vacuum reservoir as well.

[pyro]

My issue is the flowmaster 40 on the truck doesn't allow me to hear such faint noises. I still seem to have very weak vacuum at the actuators. I picked up another selector and two actuators. The selector didn't seem to.make any difference. I know that if I push the actuator in by hand w the vacuum on, it will hold itself in, but I still don't have enough to hold the one that is hooked up to the defroster door.

I checked my vac canister and it doesn't seem to be leaking at all. Could it be the rubber lines that I bought to replace the thicker (original) lines I had before?

[pyro]

Apparently both selectors are leaking...I just said screw it and added a T fitting and called it a day.