Where to connect MAP sensor VAC line
 

Tried searching and couldn't find anything.

I've been looking over the hitmans site and he has a pic of the UIM. The nipple he says to connect to is the bottom one on the side of the UIM that faces the front bumper. I don't see VAC there, but I do see VAC out of the bottom nipple on the side that faces the firewall. Same thing?

Right now my MAP sensor is connected to a nipple on the LIM. Will it make a difference if I move it? Maybe halp my idle?

Thanks for the help.

S5 FC Streetport w/ single upgrade 550/1600 and all the goodies.

-Kenji

The top nipple of the three on the front of the UIM is apparently the best source for the MAP sensor.

Then the bottom nipple on the front. It surpises me that you don't see vaccuum there, because you definitely should!

I'm not seeing any VAC at all on those nipples. I'm currently running a FC3Spro.com modded throttle body. Could that be the reason I'm not seeing any VAC? If it makes a difference, there aren't any VAC lines connected to any of those nipples on the UIM. The only thing is a cap that I installed on the bottom nipple on the side that faces the firewall.

Anyone know what might be wrong?

-Kenji

Hook it up to the bottom nipple of the three located on the front side of the upper intake manifold. That's the cleanest signal there is.

B

Like I mentioned above, I'm not seeing any VAC on any of the three nipples on the front side of the UIM. I only see VAC on the bottom nipple on the back of the UIM (which is currently capped off).

I'm gonna put everything back together tonight and tomorrow. I'll double check once the car is running again.

Next question would then be this. Assuming that I can get VAC from the bottom nipple. I will only hook up the MAP sensor to it. So where should I connect my boost gauge, boost controller and fuel pressure regulator?

-Kenji

Well, I'm screwed.

I managed to ruin one of my hose ends tonight so I can't reconnect the oil return line. Now I'll have to wait until Tuesday before I can get a new one.

So that leaves a little more time to nswer the above question. Can I run my MAP, Boost Controller, Boost Gauge, and Fuel Pressure Regulator all off of the same VAC source?

Also, is there really any difference between the VAC reading I would get from the nipples on the front of the UIM and the ones on the back? If not, I'm going to connect my MAP sensor and everything else to the nipple that I'm getting VAC on in the back. I double checked and as of right now, my MAP sensor, Boost Controller and Fuel Pressure Regulator are only seeing VAC from one runner (second one). Also, my Boost Gauge is only hooked up to one runner as well, but its not the same runner as the MAP sensor and everything else. Not sure if that would make a huge difference, but I'm going to rearrange everything anyways.

-Kenji

here

Ok, I understand that everyone is hooking their MAP sensor to the botton nipple on the front of the UIM. And I appreciate the help and the pics, but no one seems to be remembering the part where I said I DON'T HAVE ANY VAC THERE! For whatever reason I don't know. Maybe the shop that did the work sealed it from the inside or something. I tried to blow through it and I couldn't so it is definetly blocked off somehow.

The only question I have left is CAN I RUN MY MAP SENSOR OFF OF THE BOTTOM NIPPLE ON THE BACK OF THE UIM????? That is the only nipple that has VAC on my UIM.

-Kenji

BDC, I do use the bottom one as well.

But, didn't one of your buddies on teamfc3s do a test with a gauge and determine that the front top gave the strongest signal?

---

Kenji, I use the bottom REAR nipple on the UIM for my boost gauge. It works just fine for vac and boost. Not ideal, but it should be fine for Haltech MAP sensor.

Thanks eViLRotor. I think I'm gonna try running everything off of that nipple and see what happens.

I'm also going to take a closer look at why I don't seem to have VAC on that front bottom nipple. Maybe I can open it up again and use that for the MAP and the bottom on the rear for the Boost gauge, controller and FPR.

Keep it comming guys.

-Kenji

Well, mystery solved. I separated the TB from the UIM today and fould that all 3 front nipples and the top 3 rear nipples had been filled with silicon. That is why I'm only seeing VAC out of the bottom rear nipple. It was the only one that wasn't filled since the opening is inside the flange and not on it like the rest of them. I tried to open them back up, but it was no use.

So for the hell of it I connected my MAP sensor to the bottom rear nipple after I got the car started and there was no noticable difference. Looks like this will all have to be done with timing and fuel. Although I'm a little nervous trying this myself when the dyno day is so close.

Maybe I'll just wait and let Steve do his magic.

-Kenji

Of all the tiny 3mm(?) fitting off the rear of the UIM, only the rear bottom most fitting is vacuum.
The top two fittings are pre-TB or 0 to + boost only.

Of the three fittings up front, both the top and bottom fittings are vacuum.
The middle one is pre-TB and 0 to + boost only.


-Ted