Help! I am trying to sort my way through the maze of brittle vacuum hoses to replace the bad ones.

I had to replace the 4 port VRV valve and found the green vacuum line running from it was disconnected. I hooked it back up, but could not get it to hold a vacuum. According to the diagram under the hood, this line runs to the EGR valve - so my EGR was effectively not working.

Tracing the hose, it goes to some valve, then splits to 2 ports on the EGR valve. My question is what the hecl is this valve and should I be holding a vacuum?

Thank you for the help,

Nick



Sorry for the crappy pic, but it is the green line from the VRV to the EGR.



What in the world is this thing with the reddish orange hose running to the base of the EGR and the black hose behind it (attaches to the top) that runs to the top of the EGR?

 

here is a picture of what it looks like:

 

That thing throttles the vacuum to the egr, according to the back pressure from the exhaust. That's why the hose is orange, it's high temp silicone because exhaust runs into it. This is one of the ways they use to try and adjust the amount of egr according to engine speed, instead of the egr just being "on" or "off".

That's also why messing with the exhaust system messes up the emissions of the engine. It all works together. Less backpressure from the exhaust means less egr to the engine.

 

So you mean that it is okay at this point? I still sort of do not understand it. Is no vacuum to it at this point okay? Should I bypass the exhaust port and just run the vacuum line to the top of the valve?

 

If you run the line right to the valve, then engine will probably have rough spots in the acceleration. That's because the egr will be full on when the vacuum hits.

Maybe this will help. If you want to test the little valve thing, get the engine running, take the egr vacuum line off, but leave all the rest of the lines to the engine hooked up. Take the orange line off, and get another vacuum line that you feel like putting your mouth on, plug it in the valve thing where the orange hose went, and then blow on the hose. Each time you blow on the hose, you should feel vacuum passing through the little valve thing.

 

Thank you for the help. I took the thing off as of this point. While it was off, I tested it and it seems fine. I am just a little lost if I should put it on since I have a little more free flowing exhaust, or if it will affect it at all. I have not test driven the truck yet, so I do not know about the acceleration. I was curious, why do the manual trannies not have the valve?

 

I can't tell you why some have it and some don't. All this emssion stuff is sort of tacked on the engine to try to make it run cleaner, and it's usually a real mess with not much support from anyone to keep it going. Some people really don't like EFI, but it sure did clean up the engine compartments.

You can try running it with no egr. Things to look out for if you do;
Pinging with light loads on the engine and lots of free-way driving
The engine may run slightly hotter.

Each engine seems to react a little different with the EGR disconnected, you may or may not see any problems. If you decide to not run the egr, make a solid gasket out of thin sheetmetal or aluminum flashing, and put it underneath the egr to block it off. Many times the egr will leak a little bit, and it will cause a slightly rough idle. If you are not going to use it, you might as well block it off completely to prevent that.

 

I was actually hooking up the EGR. The original line running to the valve was broken, but left attached. The eng coming from the EGR was capped, but the end coming from the switch was just open. I tied them back together in the hopes of getting it functional again. It will hopefully pass smog tests now too!

I was only asking about the valve thing. I intend to run this again.

There is so much crap piggy backed onto everything else with this engine!

Thank you again!

 

You don't mention the year or engine you're working on so I'll make an
assumption based on the link below your nick... In any event, a book like the
following would likely help you greatly:
1986 FORD, FORD TRUCK, LINCOLN, MERCURY Full Line Emissions Diagnosis Shop Manual [eb1030N]

 

Well, I took the truck out and it ran like trash. Idle was rough and low. I put the funky valve thing back in and it runs great!