I picked up this map sensor today, first was told it was a 2 bar, but then my friend said he looked it up and it was a 4 bar?

Only clue is faintly burnt into the pigtail side is the words
Assembled in Hong Kong
7265

Hmm. any ideas? Ive tried searching but to no avail, im trying to get my ecu basemap'd tomorrow and could really use this info.
Thanks!

Sorry for the blurry pictures!
Any help is much appreciated!

 

it resembles a gm 3 bar.

 

http://www.robietherobot.com/storm/mapsensor.htm

 

Yeah but there are absolutly NO other markings on it, i read that post up of the GM but I assumed it would be stamped GM somewhere on it.

 

Test it and figure it out? Why'd you buy it if you don't know what it is? Sounds pretty stupid since the map sensor is the most important sensor on your car.

 

i know can test the voltage to figure out which bar the map sensor is. not to sure what voltage 3bar map was...someone can fill me on this

 

That would be very cool if someone could explain how to test using voltage.
Because right now im just on a rich basemap with stock map sensor, but I'm going to get a tune next paycheck so I would like to use it haha.

Any help appreciated!
-Ethan

 

Get a 5V DC power source, pressure chamber(Piece of PVC piping capped off), 3 vacuum nipples, a boost gauge, vacuum pump(something to bleed brakes), a bike pump, vacuum line, map sensor, & multimeter.

Take your capped off piece of PVC, and thread in 3 barbed fittings(vacuum nipples). Using your vacuum line, hook up 1 line to your boost gauge, 1 line to your vacuum pump, and 1 line to your map sensor. Deliver power to your map sensor. Use the multimeter on the map sensor to monitor voltage output.

Then take your pump and start varying pressure. Bring it to -2psi. Write down the voltage at that pressure. -4psi. Write down the voltage. Do this until -14psi.

Take your bike pump and do the exact same thing except you want you are going to want to find your max pressure. The max voltage output on that sensor is roughly 5V. So if at 10psi, if the voltage is 3V, keep pumping. If it's 4.9V, it's maxed out.

Bring back the data and post here and I'll analyze it for you.

OR

You can buy a map sensor from a trusted source instead of some dude on the corner.

 

haha what a dick...

 

I told him exactly how to find out what kind of map sensor he has via a scientific method. If I knew an easier way, I'd help the guy out. Map sensor is one of the most important sensors on your car, if not the most important sensor. I don't think playing the guessing game is appropriate on such an important part of the car.

And yes, I am a dick.

 

That's far too complicated to just test if it's a 3 or 4-bar sensor. We already have an idea what it could be when powered but not on a manifold:

2bar = 2.5v at sea level
3bar = 1.7v at sea level
4bar = 1.3v at sea level

All you do is give it 5v and ground to the appropriate wires, then measure the voltage between the output/signal wire and ground. With the port exposed to ~14.7psi absolute, or ~1bar, you can then do the math. The complicated procedure would only be for a 100% mystery sensor, but you'd need some VERY precise equipment to even attempt an accurate pressure/voltage graph.

 

Not really. "AEM" sensors don't follow that rule. That sensor is some Chinese knock off. Most likely it followed GM's sensor's specs, but each GM sensor had different specs. I wouldn't trust going on a hunch. If you are near sea level and the bike pump and boost gauges are both reading similar, do you think you are 6psi off? Com'on, my procedure it plenty good enough to figure this stuff out. If you're really concerned, check the math the ECU guys do. Most of them do it wrong

 

haha what a procedure. Honestly right now im just running stock map and having clearance problems with my down pipe, so that is the current battle. I will test it in the next couple of days and post up results.

 

Clearance issues with your down pipe and map sensor???? huh?

 

Down pipe for my exhaust is gonna hit my already half sized radiator. Gotta get creative.