i just tapped the acv block off plate for the boost gauge but im not getting any vacuum or boost off of it once the car is started. ignore the color and rtv coming out the side. i know its not leaking cause the car idles but when i pull the vac line off the car still idles and doesnt die so i know its not pulling vacuum.

 

Where does the connection go on the backside of the plate? It looks like you connected it to the port air path, which is not going to work at all if the check valve has been removed too. That'll just let exhaust gas into your vac line.

 

ok so should i install it into the smaller plate to the left? will that work?

ive always seen to install the nipple in this spot. is there a difference between an s4 and s5 for this install?

 

Don't move it to the other plate - thats for EGR.

I'd eitehr move that line to a T on the existing vac line, or tap a runner directly. Placing the nipple on the ACV plate in the wrong spot can equal no reading. I'm not a of tapping that plate.

 

Tap into the line above, that's running to the flange of the upper manifold.

 

when i put a T fitting on the other line i dont get enough pull for the BOV.

when you talk about tapping a runner into it directly where do you mean?

does anybody have any pictures of the best place to put this?

 

Take the UIM off, drill a hole in an intake runner, thread it, screw in your threaded nipple and stick your line on it. Anywhere in the intake path will let you pull vacuum/boost.

The problem with tapping into an ACV blockoff plate is that you have to stick it in exactly the right place. The top nipple on the ACV gets connected to vacuum, so you can track down the small opening (on the LIM) that connects there and use it.

 

All those nipples on the UIM...you can't borrow one of those?

 

Is this car running a stock ECU and MOP? Just curious as to what nipples are still being used on the UIM near the throttle body.

As described after your post, I'm talking about directly tapping into the runner feeding the engine. Drilling a hole, tapping threads into it, and installing the barbed fitting. A good example of a spot is a JDM lower intake. You'll note that they pull vaccum for the brake booster off the rear secondary runner, at the very top of the LIM using a banjo bolt/etc. I'd use that same spot, you'll be able to stuff a rag far enough down the runner that you won't get shavings in the engine and won't have to pull the LIM.

 

on the throttlebody, the backside nipples(pointing to the firewall) dont read vac; only boost. the ones pointing to the front of the car all read vac and boost. tap into one of those lines.

 

Really?

I have to try that.

 

no i dont have the stock ecu or mop. all emissions are removed and throttle body mod done.

ok i see what your talking about now. im about to head over to a friends house to finish the work up and ill report back as to which way i choose to do.

^^ im gonna try that too since i dont have any lines there.

 

any body have any pics of there install? id like to get an idea of a good area to put it in.

we didnt do it tonight.. we started drinking and decided to do it in the morning lol

 

If you use the nipples on the UIM near the throttle body - the forward facing ones as mentioned will provide negative and positive readings. The lower most niipple gives the clearest signal in my experience - I use that for my MAP sensor. The uppoer one being a little larger I use for the BOV. You could use the middle one for your gauge.

 

ill check that out and see because i tried it last night and i couldnt get a reading off the top nipple. ill try the others in a few minutes.

also im wondering if this will work on mine because i have no lines running to those nipples and they arent capped off. just curious because if they do have positive and negative readings then shouldnt that be a source of a vac leak right now?

i feel really dumb because this is such an easy install but i need to do this the right way.

 

For the nipples on the back of the UIM, the top 2 should be vac/boost, while the larger bottom one is metered air only (for the oil injector bleeds normally). I know at least one of the back ones should work since it normally runs to the primary fuel injector bleeds.

If you still can't get a signal off of any of these nipples, make sure your throttlebody spacer isn't in backwards. Maybe it got flipped?

And YES, you should be capping unused nipples. You'll have all sorts of leaks with them wide open.

 

If you tap the blockoff plate for the ACV, you have to tap in the right place and make sure the gasket isn't blocking the path of vacuum. There are three specific places you can tap and install a nipple. One is opposite where the original boost sensor nipple was. The next place is opposite where the anti after burn valve, internal to the ACV, is located. The third place would be there the anti after burn valve fed airpump air into the runner.

On the back of a series four USA car, there are four nipples one above the other. Only ONE is vacuum. That is the bottom one that feeds the double throttle diaphram thu the water thermo valve. The large one is for feeding AIR TO the oil injectors spider. The others feed AIR to the primary air bleed nipple inbetween the two oil injectors on the lower intake manifold. The last one is blocked off. It was originally meant for the SubZero assist valve that has been removed years ago.

The nipple that feed AIR, have a passage inside the throttle body that exits PRIOR to the throttle plates i.e. no vacuum on them.

 

.