I found a MAP sensor, GM part #9373269. I was wondering if anyone knows anything about it, or is using it, the part description says turbo pressure sensor.

Jason



USACi =>146.9db
14.88 @ 90.73MPH =>GM Charger, Motor Mounts, Catback exhaust

that won't work with our PCM.




I was a retard, and now I'm permanently banned.

The key to using a MAP sensor... or any other sensor for that matter... is having something that can make heads or tails of the output it's providing.

and since our PCM's do not read boost... yea you get the point.




I was a retard, and now I'm permanently banned.

Wouldn't the ECU read it correctly, if you were to have the SC reflash, and if it were or is a 2bar??

I mean it looks just like a MAP sensor, although I'm not posotive. that's why I want to know if anyone is using it for a MAP under boost with or w/o the reflash or whatever.

Jason



USACi =>146.9db
14.88 @ 90.73MPH =>GM Charger, Motor Mounts, Catback exhaust

^ The computer can't understand boost if its not programmed to. Lets run through the basics of why...

MAP sensor output (regardless of BAR) is usually 0-5 volts

Lets assume that 0 volts = Low reading extreme
Lets also assume that 5 volts = High reading extreme

Now, on a 1 BAR map sensor, it can read anywhere from 0 BAR to 14.7 PSI (1 BAR). So using the voltages from above, 0 volts = 0 BAR, 5 volts = 1 BAR.

Lets take another assumption and say that the computer provides fuel in a linear relation to the voltage on the sensor ( 50% voltage = 50% fuel, 75% voltage = 75% fuel).

The computer is calibrated so that when it sees 2.5 volts, it delivers half the maximum fuel amount.

Now up that to a 2 BAR map sensor, so 0 volts = 0 BAR, 5 volts = 2 BAR. 2.5 volts = 1 BAR, so when you put that on your car, and hit half throttle, you need 50% fuel, but since 2.5 volts = 1 BAR, then 1.25 volts = .5 BAR, you are only getting 25% of 50% fuel, you are getting half of what you need.

Long story short, running a 2 BAR map sensor on a computer that is not calibrated to read a 2 BAR sensor will result in a lean condition, since at the maximum throttle if you could hit 2 BAR, the computer thinks you are at 1 BAR and only delivers half the fuel necessary, at any point of throttle or acceleration.





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You guys can and do overcome fuel issues, but it requires additional hardware. The real killer imo with the 2 BAR sensor on 1BAR table is timing. Believe me when I say that timing is everything. Lower voltage from the MAP indicates more vacuum, which gets more spark advance. The 2 BAR sensor actually provides slightly less than 1/2 the voltage of the 1 BAR sensor when the engine is at 1 BAR pressure. The computer will use advance values obtained from the 50, 40 or 30 kpa regions of the spark table when the engine really requires lower timing values obtained from the 1 BAR portions of the table. And as boost builds in the intake, timing values will be drawn from the 50, 60, 70 kPa regions of the table, which are still more advanced than the 100kPa (1BAR) entries at the same rpm.

At least with the 1 BAR sensor, as soon as the sensor sees pressure spark advance is reduced to the 100kPa values where it stays.

Now with a boost friendly calibration, things are different. If the sensor output matches the range of voltage expected by the calibration, you're all set. The sensor # that you've posted, I believe I've also posted. It's from GM trucks with a 6.6L Duramax diesel. GM sometimes does some funny things with sensors. Because a diesel engine has no throttle to restrict air, it never sees vacuum. It's *possible*, although unlikely, that the sensor is designed to read from 1 BAR to 2 BAR only. The factory service manual would clear this question up.

-->Slow

so this means that by adding the 2 bar map with the new eco or 2.4 supercharger flash the pcm will be able to read boost because the addition of the 2 bar . ok so does this mean that even if you have a 2 bar map system that can see boost can you still run becasue the change in fuel and spark will only come during boost?


"Kick azz is my boost hero!!! "

Jcavi wrote:so this means that by adding the 2 bar map with the new eco or 2.4 supercharger flash the pcm will be able to read boost because the addition of the 2 bar . ok so does this mean that even if you have a 2 bar map system that can see boost can you still run becasue the change in fuel and spark will only come during boost?

I'm not sure what you just asked.

If you're asking whether you can still run with the 2-bar MAP sensor WITHOUT the reprogramming if you stay out of boost... here is the reason.

It's just like gear ratios. The closer to zero you get... the closer the values are to one another.

Note that these numbers are just theoretical examples to get the point across.

If you're getting 1 BAR into the engine then the 2 BAR sensor is telling the PCM you're getting half of what you actually are. It's reading 2.5 V and you're only getting half the fuel you need so you're running really lean and could cause damage.

If you're running at 2000 rpm with the throttle almost closed though... then if the 1 BAR sensor would have been giving 0.5 V, the 2 BAR sensor will be giving 0.25 V and the difference really isn't all that much in the overall scheme of things. Sure, it's running a big lean, but you're not pushing it so it's not getting too hot and you're fine for the short term.

It's now off by 0.25 V instead of by 2.5 V which is an order of magnitude in difference.

See the point here?