So I have a 98 Xj I bought and rebuilt the engine completely, when I go to plug in all the vacuum hoses I couldn’t remember which when in to the heater valve. The only one that makes sense it constant sucking in air and when I plug it in to the heater valve the engine runs rough and boggs out. Can anyone help we figure out the right way to connect them.

 

1998 had no heater valve.
do you have a pic?

 

This is my engine and you’ll see it there.
This is before I rebuild the entire thing. It looks different now but it’s the o my pic I have where you can clearly see the valve.

 

What's the 10th character in your VIN? It represents the model year. A 1998 should be a "W".

I see the valve but as Cruiser said, they were deleted in '97.

 

I know they were deleted in 1997 and up and I might have to do that to this one. Im wondering if someone just switched the hoses before I bought it. But now I’m left with a vacccum line I can’t seem to find where it goes.

 

So I just check and it is indeed a w

 

So I have Yellow ~ Evap charcoal canister above the rear axle Red ~ to valve cover breather Blue ~ I need help with Also with one of the bigger tubes from that charcoal canaster does that go in to a filter in the engine bay ?

 

That blue one is the vacuum source for your HVAC system.

 

I’m assuming you mean this right ? But when I connect it there the engine Boggs off runs rough.

 

See the white splice connector in the line above? That should be a Tee connector with the open line connecting to it. The open line connects to the dash control and operates the vent doors. If you turn on your blower, it will now only blow out the defrost. Not sure you have enough good hose left to make the connection. Perhaps the previous owner had issues with it and decided to bypass it.

 

On '96 and older, there would be 2 hoses coming out from that area. One is the vacuum supply (like the one you have now), the other would go to the heater valve. So when you turn the hvac control to any "heat" setting (including Defrost) the valve would open coolant flow to the heater core. When you select something other than heat (AC or off), the valve would bypass the core.

Is there a vacuum line on the heater valve now?

 

Okay so what I did is connect the line I marked I. Blue to the vent door opener line coming out there. The blower is now blowing how it should vent doors are opening. Reasons I didn’t tee it off how it’s originally suppose to is because I’m going to do that heater valve delete and just run the hoses straight through with no heater valve.