Working on cleaning out my engine bay (preparing for big project), I need to know where I can hook up my oil injector air bleeds and fuel injector air bleeds.

From the searches I have done, it seems like the fuel injector air bleeds use a vacuum source, but the oil injector air bleeds just get fed straight air? (from the intake tube before the TB, after the AFM).

I found this picture I have been using as a reference:

http://www.globalvicinity.com/images....2937_3049.jpg

As you can see, they have the fuel injector bleed lines hook up to the TB, but it looks like they reused the metal rack under the UIM (part of the rats nest) that turns the oil injector bleed lines into one then routes them into the intake (where I stated earlier) and also into an electric valve which hooks up into the big vacuum line on the drivers side UIM.

My first question, what is that electric valve do that splices into the oil injector lines and routes back into the intake manifold (when you already have the other line going to the intake before the TB after the AFM)?

Should I keep this valve or toss it? Where should I route my oil injector bleed lines (vacuum or fresh air/where)?

Is it safe to route my fuel injector bleed lines to where that picture stated (looks like a source of vacuum) or do they also need fresh air?

Thanks again and sorry for the long post.

 

I was looking at this rotary resurrection writeup and I see they blocked off their fuel injector bleed off lines. Is this safe to do?

On their write-up they merge all 4 oil injector lines but don't state where they go, so I am still stuck on this part...

 

Ok I found the answer here it is for anyone in the future:

1. Fuel Pressure Regulator (FPR): vacuum
2. Pressure (Boost) Sensor: vacuum
3. Fuel injector air bleeds: metered air in front of butterfly valves
4. Oil injector air bleeds: metered air in front of butterfly valves
5. BACV: metered air in front of butterfly valves
6. Fuel lines: fuel


Note: all other vacuum ports should be capped

From: http://howto.globalvicinity.com/gv_w...i=44&co=1&vi=1

 

Got a picture of the valve you're talking about here? It sounds like you may mean the air bypass solenoid (also called AWS). If that's what it is, you can remove it, since it's useless.

Air bleeds can be capped, but they're useful. The air forced in helps atomize the fuel and allow a more complete burn.

The oil injector vacuum spider (4:1 valve) will always get connected to the largest nipple at the TB. It's about a ~6mm nipple, while all others are ~4mm. Any other metered air source will work too, as you noted.

 

In stock form, my S5 engine routes the oil injector lines into the intake tube, where it has an opening for the BAC and then one for the oil injectors, right after the AFM before the TB. The valve I believe you are right it is the AWS, it "T's" into the 4:1 valve but then redirects it into the back of the UIM (via the AWS). I am guessing that big nipple the AWS hooked up to on the back of the TB is a vacuum source correct?

What I am going to do is cap off the big nipple on the back of the TB (the one the AWS hooked into) and cap off the other big nipple on the intake tube that use to run to the oil injector spider and just run the fuel and oil injector air bleeds off the same line 7:1 (eliminating the oil injector metal spider)

Would there be any problem doing it this way? Thanks again.

 

I was second guessing my statement about the 6mm nipple after I typed it. I forgot the S5 NA is the only FC that doesn't have the oil injector spider connected to the TB.

The AWS receives metered air and directs it into the manifold to boost cold start idle. The large nipple (~3/8") on the driverside of the plenum is where it feeds in, so it is a vac source, but that's not how it's used.

Lastly, the air bleeds and oil injectors all get metered air, so splitting them off of one source will still work.