How to verify MAP sensor is working?
Thread Starter
Intermediate
Joined: Dec 2006
Posts: 48
Likes: 0
From: Prairieville LA
How to verify MAP sensor is working?
Still fighting low idle on my 82. Checked the timing (6 degrees BTDC), replaced the coolant temperature switch due to corroded wiring, checked the shafts on the throttle bodies for excess play. Idles okay in neutral or park, but ~ 500-600 in drive. I disconnected the MAP sensor and the idle did not change. Is there a way to verify if the sensor is bad before swapping it out? I still need to check the TPS voltage, but after that and the MAP sensor I'm running out of ideas.
Safety Car
Joined: Aug 2000
Posts: 3,711
Likes: 43
From: San Antonio TX
Test the output voltage. Best to use a hand-held pump, but in general, the higher the manifold pressure, the higher the voltage. Voltage would be highest with the key on, engine off (full atmospheric pressure). Voltage would be lowest under low pressure, like if you **** the throttle. First check the electrical to make sure the sensor is seeing 5V reference, and that the ground shows no resistance. The output voltage from the senor will be the difference between the 5V reference and whatever the targets are at specific vacuum levels. I don't know what they are for your sensor, but as long as you get variations based upon different vacuum levels, you have an idea the sensor is responding and is probably not the cause.
Burning Brakes
Joined: Jul 2007
Posts: 1,166
Likes: 284
From: Springfield MA
St. Jude Donor '10-'11-'12, '19, '21
Ken, 6deg. is way to low for an 82. Bring it up to between 8-10deg. I run mine at 12deg. and it runs great now. A new (85-87) fuel pump will also help a lot. Most of these 82's are not "turn key cars" they like to be played with. By that I mean, there is always something to adj. or change or add to.
Just my thoughts.
Good Luck! (try the timing, it should make a diference).
Dave
Just my thoughts.
Good Luck! (try the timing, it should make a diference).
Dave
