MAP Sensor issue

[rmvlt1100]

Originally Posted by clinebarger

A 1-BAR MAP sensor is a 1-BAR MAP sensor. A LM7 & LS6 use a 1-bar map sensor. They function the same way, You could wire in a MAP sensor from a '83 cross-fire Camaro on a LS & it would work.

Even with a 2-BAR or 3-BAR the voltage would change....though be wrong for a N/A 1-bar tune.

Check your wiring, Though buying a aftermarket sensor does make me question the part.

A 1 BAR MAP sensor reports barometric pressure times one, which is approximately 14.7 psi or 30in/Hg (inches of mercury). As an example, a typical three wire MAP sensor has 5 volts and ground to power the circuit. The signal circuit, or return voltage to the computer, is about 4.5 volts at barometric pressure of 14.7 psi; this measurement is taken at key on engine off. The sensor can withstand about 1.5 BAR of pressure, but the return voltage will peak out at about 4.8 volts. This type of sensor is designed for a normally aspirated engine to read a negative pressure, or vacuum, at a typical barometric pressure, When vacuum is high (idle, decel) the sensor will read low voltage....Around 1.50 volts.

Clinebarger, Thanks for the info. I did double check the wiring for voltage and resistance. I also did the shake test with the help with help from a friend and the wires seemed fine. I will take the MAP sensor back and get another one to try. I will try to use the one off the truck intake withsome adaptors. I'm not sure the next step after that if nothing changes. At one time I thought that maybe it was the scanner, but, everything else seems ok through the scanner. I don't think the truck will be on the road this year. (School tuitions are being paid so the money for the truck has slowed down.) Maybe I can loaded on the trailer and get it to a tuner or have someone come by with a tuner program to check it. Any way if anyone else has any ideas please let me know. This is the first time I ever worked with an LS style engine and so far it hasn't been to bad. Thanks again for the info. Robert