LQ1 MAP Questions (Page 1/1)
fliphone NOV 18, 02:29 AM
Hi all! I'm currently working on a swap and a possibility that I didn't even think of was pointed out to me. The swap is a 96-97 LQ1 motor (Pic 1) using a MAP sensor similar (if not the same) as a series 2 NA (pic 2). I'm using an earlier wiring harness that shares a similar MAP with a 3.8 series 1 NA motor (Pic 3) and I am wondering if i can just splice in the new connector onto the older harness/computer. I know GM parts are often compatible so it didn't even cross my mind to check into this before now. I'm having trouble tracking down info on this setup so a plan B would be to run the earlier MAP sensor. If that does end up being the method of choice, am I able to just run a vacuum line to the sensor and call it a day? Or do the sensors need to be placed in specific locations like MAF sensors? I apologize for the crappy grammar, its getting late but I wanted to get this question out there as soon as possible.
TIA and Cheers!
theogre NOV 18, 11:38 PM
GM use 3 MAP sensors...
1 2 & 3 Bar units.
1 Bar for NA Engines
2 & 3 Bar for Turbo & Super charge engine depending on Max PSIA they see.

So you need more data to tell if ECM/PCM are program to work w/ right MAP the engine needs even before you rewire to use a newer/different unit.

Wires are +5 volts, Ground & output & all going to the ECM/PCM directly.

------------------
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Raydar NOV 19, 04:14 PM
I have mix-matched MAP sensors before. You may find that the pins/sockets are "keyed" differently. (I was shuffling back and forth between a 2.8 and a 4.9.)
But as long as what you are using is from an NA engine, you should be okay.
If the keyways in the connector on the MAP are wrong, I believe the inserts may be removable, so you can swap them around.

As long as the MAP is connected to the main intake plenum, somewhere, you should be good. Manifold vacuum, IOW.
NOT from a throttle body port - at least not most of them.

[This message has been edited by Raydar (edited 11-19-2023).]