MAP sensor info wanted

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Jul 17, 2007 | 09:33 AM

MagKarl

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From: Olympia, WA

MAP sensor info wanted

I'm confused about what the MAP sensor is and does. I've read it stands for manifold absolute pressure. I don't know exactly what it is and how it works or whether it's hooked up right on my rig. I've got a plastic hose running from the passenger side intake plenum to a plastic box that is screwed to the heater box. There's no wiring connected to this little appendage, and this hose is where I assume you'd T in to add a boost guage. I've also got an electrical device on a bracket that attaches to the top of the heater housing that has a wiring harness and a vacuum line connected to it. Which one is the MAP, what is the other called? When I read these posts that mention MAP I can visualize people talking about both of these.

Jul 17, 2007 | 09:39 AM

c00nhunterjoe

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From: Belair md

the map is the one with the rubber hose that goes from your intake to the box on top the heater box and has a 3 wire connector on it. it stands for what you stated. its sole purpose is to read the pressure of the air going into the engine, the pcm uses this to decide how much fuel is needed, the sd's also use it to control wastegate activation. the pcm also takes the reading to infer what your boost level is simply by subtracting the map reading from baro reading, the difference is MGP, or manifold gauge pressure, the baro i believe is behind th eglove box on our trucks and should typically be around 14.7 psi or 1 atmosphere to scientists,

Jul 17, 2007 | 09:46 AM

MagKarl

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From: Olympia, WA

Then maybe mine is not hooked up right. I have a hose running between the intake and a closed plastic box that gets screwed to the side of the heater. The one that has to be removed to get #7 injector out. The device on top of the heater box has a wiring harness and a tubing port, but that port is connected to a vacuum line. That's why I'm confused and not sure if mine is hooked up right. It wouldn't surprise me if it wasn't.

Jul 17, 2007 | 09:50 AM

c00nhunterjoe

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From: Belair md

the one that has a plastic hose on the side of the ac box is not it, its the one on top, that vaccum line should run across to the intake, hang on i'll get a pic

Jul 17, 2007 | 09:53 AM

c00nhunterjoe

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From: Belair md

https://www.ford-trucks.com/forums/6...oler-pics.html
sorry not home, no camera, but this is under my hood, first pic, upper left you'll see the box with the wires and the hose on it, it runs under my cooler tube and hooks into the intake just below the orange hose, it has a nice shiny hose clamp on it

Jul 17, 2007 | 10:04 AM

MagKarl

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From: Olympia, WA

Ok, then mine's not hooked up right. Not surprising, I just figured out my #1/3 injector harness was wired backwards too. No wondor this pickup ran like crap and the seller was going broke paying "professionals" to work on it. So the plastic box on the side of the heater should be connected to the vaccum line that runs across the cowl and the MAP sensor port should be connected to the intake. That makes more sense. Thank you.