EFI plumbing w/pic

EPorsche · 12-30-2005, 06:17 AM

I just plumb in the AAV and AV after the Y rubber hose was found to have five cracks in it. It cost less than $30 for the heater hose, pex connectors, clamps (which I have to change out because they're ugly) and fuel injection hose.

flipper · flipper's Garage

Is that the Tbitz EFI? Just curious, but why did you leave the AAV on there. I thought the kit removes that piece? Nice looking intakes by the way, are those cadium plated?

EPorsche · 11:16 AM

The intakes have a high temp paint. If I was to do it again I would of went with powder coating. I read several threads that talked about how the rpms drop suddenly with foot off throttle. Plus I wanted to keep that part of the system as close to stock and I had to fix the cracked hose. I did not want to pay $160 for the hose. I do have the TBitz kit.

EPorsche · 12-30-2005, 11:18 AM

Also I did make a bracket out of aluminum to raise the AAV.

JohnJL · 12-30-2005, 01:54 PM

Very nice, and thank a lot for posting the pics....I'm close behind you now...built the MS kit and am timing the cams now...I went polish/clearcoat with high-temp paint on my intakes but would have clear powdercoated if I had the resources here...

Keep up the pics and great job!

tbitz · 01-01-2006, 01:46 PM

Looks good!

CIS experts can correct me if I am wrong, but I believe that the AAV (Aux Air Valve) is only used during starting. The valve is open when engine is cranking allowing more to bypass the throttle body to help start the car. It is effectively like holding the throttle pedal down during starting.

The "decel valve" allows bypass air during high vacuum (sudden deceleration) to keep RPMs elevated as described above. In later years the decel valve looks much like the AAV but has a three hoses instead of two. In earlier years the decel valve is smaller and looks more like the "fuel accumulator". It again has three hoses.

None of them are needed for EFI, but the decel vavle may aid in keeping the rpms up during shifting.

Cheers,

tbitz · 01-01-2006, 01:49 PM

Just cracked open the Bentley manual. Descriptions and pics in the manual page 200-7 and 200-8.

Cheers,

EPorsche · 01-01-2006, 01:54 PM

Tony,
Your right, I miss spoke. The decel valve will also go back on and I have all the hoses for that. I have a question, does anyone have a good picture on the plumbing of the accumulator to the T fitting? I seem to be missing something, I know the left goes to the accumulator and the right goes to the fuel pressure regulator but where does the middle part of the T goes?

tbitz · 01-01-2006, 02:00 PM

In earlier CIS cars the "T fitting" has three nipples as shown in the installation guide.

In later years the "T fitting" has an extra nipple that was used for the frequency valve. You need to plug this nipple.

Cheers,

mb911 · mb911's Garage

looks nice this is how my t bitz kit ended up (will be changing again shortly and this system will come up for sale That airbox system that is not the tbitz)

EPorsche · 01-01-2006, 02:15 PM

Ben,
I see you have the middle of the T going to the bottom of the accumulator, where does the hose to the left go? Is that the incoming fuel supply or return to the tank?

EPorsche · 01-01-2006, 02:27 PM

Thanks Ben I just figured it out.

tbitz · 01-01-2006, 02:31 PM

Left side of the Tee goes to the return tank via the threaded fitting.

Middle barb goes to the fuel accumulator.

Right barb goes to the EFI fuel pressure regulator.

IF you have a second middle barb fitting like that pictured below, it needs to be plugged.