Monkeyboy

Here's the situation - trying to install a vent mount VDO gauge. All went well except I was only getting @8 vac and no more than 5psi boost (chipped). Assumed it was a kinked nylon tube line, so I am troubleshooting today.

Took the gauge and connected it directly to the line coming off of the manifold - perfect - @16 vac.

Install the T connector and hook gauge to a short run off of the T - nothing or same as before - @8 vac. Appears that the T is the problem.

First off, am I connecting it to the T correctly?
On the T there is a straight thru (which is a bit bigger opening) that I am connecting to the line going from the manifold to the connection under the manifold.
Then the T portion (a smaller diameter opening) which I am connecting to my boost gauge. I do feel/hear some vac coming through this - but it obviously in't enough to show correct levels as if my gauge was directly connected to the manifold.

thoughts?
am I using the correct T side for the boost gauge? Could my T be messed up?

K.C.Miller

I am about to do the same mod. I'm tracking this thread.

Monkeyboy

The nylon hose that comes with the gauges is a royal PITA to work with. I used the nylon line for a short run from the vent mounted gauge to just under the dash. Then I fed @4" of the nylon hose into normal vac line which I routed through the firewall / ECU / Engine bay into the T connector.
I kinked the nylon stuff a few times when working with it - cut the bad part out. Much easier with a short run only.

I tapped power from the 75x terminal
Grounded the other connection to the top bolt near the fuse panel.

The T is my problem now - after that I should be good to go.

WJM

it will stretch over the back of the gauge, or get a barb adapter

starting ...

<center><img src="http://pictureposter.audiworld.com/74942/pc030115.jpg"></center><p>

WJM

without seeing how you adapting the nylon line to the T it is hard to say what is wrong...but a t is a t

Monkeyboy

I have a second gauge and connected it with @6"nylon line. I pushed the nylon line into @6" of vac line and zip tied it secure. Now I have a portable test gauge.

I then pushed the open nylon line of the test gauge into the (smaller) T fitting - no vac registered. I pushed that nylon line again directly onto the manifold connection - perfect. Therefore the problem (in my mind) is that the T opening is too small or the T itself is wrong/messed up. I do hear and feel some vac coming from the open T connection

Monkeyboy

I need to connect the boost gauge to the larger T inline connection and use the smaller connection to feed the line that goes under the manifold.

Monkeyboy

It doesn't match the install instructions - but it works fine if I connect the manifold vac line and boost gauge vac line in the straight section of the T fitting, then the smaller offshoot to the T goes to the vac line under the manifold.
Not sure if that is right but no CELs yet and the gauge indicates what it should.

Monkeyboy

My T that came with the gauge has a larger straight thru opening and a smaller (restricted)offshoot opening. Not sure if that is how it should be?