Hey guys,

Top of the engine on the pass side there is what I believe is called a Air Management Valve / Diverter Valve. It has 3- maybe 5/8" air hoses going to it BUT there is also a very small, maybe 1/8" pink or faded red tiny plasic hose coming from it. IT IS BROKEN OFF .

I am GUESSINg it is simply a drain, am I right or does this need to be connected to something somewhere else?

THANK YOU in Advance!

Brad

 

Hello and Welcome to FTE!

I'm not sure if this a 4.9, 5.0, 5.8L, etc. That is a 3/32 vac line that should run to the TAB or TAD solenoids.

I've listed a link that will provide a vacuum line diagram for a your particular vehicle. If you can't find the VECI label for your model truck located on the under side of the hood. Scroll down to the bottom of the page where you find VECI diagram's. It will ask you for a your Calibration of your vehicle. It's located on the driver door jam.

http://www.motorcraftservice.com/vdi...&menuIndex1=19

If you are still unsure, please post back with Engine CID and someone else can help you further.

 

THANX! For the reply but...

I think it is part of the positive pressure air pump system and not vacuum.

It is a 7.5 / 460 gas. 1990 F250 SuperCab 4x4 Auto Air...

Here is a pic.

CLICK HERE


or;

 

Like timbersteel said, that is a vacuum line that goes to the TAB controller. The vacuum controls the air diverter valve behind the block.

There is slightly pressurized air going through the valve. You are right on that count. It controls the air flow to the cats.

The two problems with that not working are: 1) cats not getting the warm-up air shortening cat life; 2) vacuum leaking from the TAB affecting engine performance.

 

p.s. the vacuum leak would be from the TAB not that pink line.

 

Thanx a LOT for the input guys...
I am trying to learn at the same time here, what is what...

I "guess" I could mickey mouse this back together with hose slipped over the pink but I betcha there are other areas as fragile as what I found broke today.
The pink tube buried in convulted tube is OK/pliable leading me to believe the little UV rays from the sun it gets are what tweeked the pink tube into it's fragileness where exposed.

I am having a hard time equating some of these abreviations though. A little research fruited the following, any mistakes relative to these diagrams?

Abbreviations & Acronyms*Dictionary*Definitions

TANKS= Fuel Tanks
CPRV= Canister Purge Regulator Valve
PCV= Positive Crankcase Vent-ilation
MAN VAC= Manifold Vacuum
EGR= Exhaust Gas Recirculation
EVR= Electronic Vacuum Regulator
TB OR TAB= Thermactor Air Bypass
V CK V= Vacuum Check Valve
SOLV= Solenoid Valve
SRV= Secondary Runner Valve
VRESER= Vacuum Reservoir

 

That sticker does not much does it? It shows the TAB (TB) but not the lines!

A vacuum line will run to the TAB from the manifold vacuum source. The second line will run from the TAB to the diverter valve. Just run a new vacuum line from the TAB to the diverter.

I *believe* the TAB will be on the driver's side of the 1990 large block, perhaps attached to the rear of the valve cover. It looks like a 2" tall small cylinder standing on end with two wires and two vacuum lines coming out of the base.