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Old 08-03-2018, 11:37 PM   #1
jvluntzel
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Default 1990 740 map sensor

Does anyone have info on the specs of it? What pressure rating? Output voltage graph or levels? Etc... It's the one that looks like the GM Map sensor

Pics for clicks


Last edited by jvluntzel; 08-07-2018 at 11:06 AM..
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Old 08-04-2018, 12:13 AM   #2
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It is a GM map sensor. They’re dirt cheap. 2 bar? 3 bar? Idk
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Old 08-04-2018, 12:09 PM   #3
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Google the part # and you may get a cross reference to a GM application if the parts store cant do an interchange on it.
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Old 08-04-2018, 01:09 PM   #4
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There's a graph in the regina greenbook. 1bar, linear, ~0.5volts to ~4.4volts.
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Old 08-04-2018, 10:18 PM   #5
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The mentioned "Greenbook"...

http://www.volvowiringdiagrams.com/v...x%20Regina.pdf

It's the "Pressure sensor" graph at the bottom of page 3.
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Old 08-06-2018, 10:07 AM   #6
jvluntzel
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Thanks guys!

I pulled it out and got the part # and got pics:

The sensor is a GM 876 1057 ( 1 Bar map sensor made in the 57th day of 1991)



I also got a GM map sensor from a supercharged GM at the junkyard (886 5207 2 Bar map sensor made in the 207th day of 1995)



Here is the voltage chart for the 1 2 and 3 bar:


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Old 08-06-2018, 12:58 PM   #7
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psi on y axis volts out on x axis
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Old 08-07-2018, 10:09 AM   #8
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Update: Car does not like the 2 bar installed in place of the 1 bar. I expected this but dang that sucks :/
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Old 08-08-2018, 02:11 PM   #9
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Wouldn't you have to match your MAP sensor to you injector size just like lh2.4? So bigger MAP, bigger injectors then it's happy? Otherwise bigger MAP same injectors, lean fuel and boom.
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Old 08-08-2018, 08:45 PM   #10
jvluntzel
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Quote:
Originally Posted by sbabbs View Post
Wouldn't you have to match your MAP sensor to you injector size just like lh2.4? So bigger MAP, bigger injectors then it's happy? Otherwise bigger MAP same injectors, lean fuel and boom.
Its more of the voltage signal level provided to the ecu. As shown in the graph. the voltage out at 10 psi for the 1 bar is much higher than the voltage out at 10 psi for the 2 bar. This provides a skewed value to the ecu and it doesnt know where it really is. To correct this I would need to adjust the map in the ECU, but until I find one of the Regina ecus with a chip I can tune, I am SOL.

One oddity is that running the 1 bar (stock) sensor, this means 0 positive pressure, but my car is running4 psi of boost (essentially 18.7 psi total) which is above what the stock sensor can read, but I am running near perfect AFRs (12.1 under load and 14.7 in vacuum). The ecu must be compensating for this somehow.
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