Engine is out of the car and I’m researching all of the sensors and vacuum lines I can eliminate since going single. One thing I can’t seem to find a definitive answer on is this lil guy



It was tee’d off 3 times and tied to the boost gauge when I bought the car. Do I need to keep this sensor? Thanks.

 

Yes you absolutely need a map sensor (manifold absolute pressure sensor). Without it the ECU doesn't know at what pressure the manifold is at and the car runs like absolute ****.

Since you are going single, you should look into upgrading the unit to a 3-bar map sensor as the stock unit only reads up to 17 psi. Even if you are not planning to boost to 17psi, it is still a good idea in case an over boost condition occurs. It just might save your engine.

 

I failed to mention that I’m running the Haltech 1500 ECU with internal MAP...vacuum line plugs into middle nipple of UIM and into ECU.

So is there any further reason to keep this little guy?

 

If that's is the case, then there's no reason for the stock map sensor to be on there.

I am curious though, what is the electrical harness connected to on the other end? By all accounts it should not be connected to anything. But it is best to check as you never know what sort of voodoo prior owners have done.

 

Assuming no electrical pirates destroyed your harness it would be fine to disconnect the map sensor. I have the Adaptronic modular which I have set up to use the internal map sensor so my original map sensor wires are not in use either.

 

I disconnected and removed it since I won’t be using it any longer. Oddly enough my last ECU, the Adaptronic Select, used an internal map as well, however it was still connected and I found my boost gauge and windshield wiper motor (???) tee’d to it via vacuum lines.

I guess we’ll see once she’s fired up again. Thanks for the help!

 

You'll find some tuners prefer using a map sensor closer to the action so to speak, rather than at the end of a vacuum line a few feet away. The manifold here has a bosch map/ temp probe directly mounted for this reason.