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rsdoherty88

Changing map sensor, retune necessary?

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I'm about to wire in a gm 3bar sensor I bought on amazon since the factory 3sgte map sensor can only read 2.2 bar absolute. Currently car has been calibrated and tuned on the oem 3sgte map sensor, for which Link ecu is precalibrated for. Besides doing the basic map calibration and selecting the correct map sensor in the settings, do all the map sensor generally read pretty accurate?  Hoping I dont have to remap the fuel table if for some reason it is reading slightly different from the one its replacing

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As long as you have a calibration for the new sensor, and the old one was also calibrated correctly, you will not need a re-tune.

Be sure to run the Calibrate MAP-BAP process once you have slected the new calibration/sensor type in the settings.

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Got it working, however I purchased a GM style 3 bar map sensor from Amazon. After installing it, I hooked up the laptop and I selected GM 3 bar in settings, but the reading was too far off and I got an error message saying it was less than or greater than 5Kpa out of range. I tried a few different sensor options until I landed on Bosch 3 bar(of which there appeared to be two different Bosch 3 bar options)and then it was within close enough range to calibrate.

 

But, will it be correct since I thought the one I bought was supposed to be GM. Kinda confusing how many options there are...

 

3 BAR MAP Sensor For Various GM Models with Connector Pigtail https://www.amazon.com/dp/B07TJG9F6L/ref=cm_sw_r_cp_apa_i_Om3uDbM2FPD66

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that link looks chinese. I've never used chinese map sensors, but I have tried to use chinese fuel pressure sensors a few times and seen badly inconsistent results.  I'd suggest pulling a genuine GM part off a junkyard car if you want to do it on the cheap. That amazon listing has a list of all the cars you should go looking for.

[edit] you could also dig up the service manual for any of the cars this came from or the GM part number info for the compatible products listed, and see if you can find a voltage->pressure calibration graph. Enter this manually into the link ECU. if your pressure with engine off is not really close to BAP, then the part in front of you does not follow the GM calibration and you should not use it unless you can find a known good calibration from the vendor (or you have a good vacuum/pressure gauge to test it yourself). I would not reccomend just trying random calibration options until atmospheric pressue matches. You would have no idea if the rest of the calibration slope matches the sensor in front of you - only the 1x point at atmospheric pressure.

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I have had inconsistent results with changing map sensors.  Switching between oem sensors i have had odd offsets and tune has needed adjustment to compensate.  I would recommend at least a double check before just calling it good when changing anything sensor related.

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Thanks guys.  I looked up a bosch style sensor abs it looks the same as one I bought with same cars listed.  It's probably a bosche sensor replica.  I'll hopefully take it for a drive today and see how my open loop afrs look. 

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Well as you seem to be guessing rather than actually calibrating correctly...yes you should have someone competent re-tune things, or at least check the map sensor scaling is correct compared to the old one.

 

And sadly, most of the GM style sensors these days are Chinese. For such a critical engine sensor.....not a chance would I use one.

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