mystery vacuum lines

[belteshazzar]

my '87 Ranger 2.3 has three vacuum lines, a red one, a green one, and a black one, that all originate around the throttle body. they go toward the passenger side of the engine compartment, however they all three have been melted. i cannot find where they would have gone or what they used to be attached to. the truck runs about as well as anything you paid $100 for would, but if i could make it run better by connecting these things where they go that would be cool. anybody know?

 

[Mark_88]

They are probably the ones that connect to the air pump...if you have an air pump it would be on a bracket at the front of the engine...and there is a vac line or two there...or should be...that is to allow the pump to blow the air into the cat...

I was trying to remember how the OEM pump worked and recalled a connection on the pump...but since I've gone electric...it doesn't matter for my truck...

 

[scotts90ranger]

sound like the lines for the EGR control solenoid, as long as the lines aren't leaking the engine won't know the difference but there's more of a chance of the engine knocking a little (hotter combustion temperatures) without the EGR valve working

 

[belteshazzar]

I don't think it ever had an air pump on it. Not only because there isn't one, but i don't see where it would have pushed the air into the exhaust stream either.

I'll have to research that EGR control idea.

 

[scotts90ranger]

the solenoid thing sits on the passenger side inner fender by the hood hinge with a couple facuum lines going to it one mine one was red and one green. On the black one, that could either go to the MAP sensor or the heater control valves

 

[belteshazzar]

the Red and Green ones did indeed go to EGR control solenoid. the black one i'm still trying to figure out.
it looks like the MAP sensor is mounted to a metal tab that sticks off the firewall in about the middle of the engine bay, and it is still connected to a vacuum signal.

 

[scotts90ranger]

I would imagine heater control then, that's on the passenger side near the blower motor, change it between heat and cool and defrost to dash vents, if it works that's not it...

 

[tomw]

If you poke around in front of and below the heater blower motor, you may find a black plastic box or sphere with a vacuum line fitting. That would be the vacuum reservoir. It provides vacuum when the engine is at wide open throttle to hold the HVAC temperature and/or mode flaps in place. If the heater goes to defrost when you accelerate, or the heater is always on defrost, you may have a vacuum problem such as a missing reservoir, or a leaking check valve.
tom