Engine check light on
Map sensor: Manifold Absolute Pressure sensor- it's a measure of manifold vacuum that is sent to engine computer; so it can figure out engine running conditions and how much gas to add for the correct air-fuel mixture.
You probably need a new sensor. I don't know what newmatic means? But, pneumatic is of or pertaining to air, so hey, you better diagnose this before buying a new map sensor- just check if your vacuum hoses are not deteriorated from age, check if you still have a good vacuum signal from the intake manifold. If you were to hook up a vacuum gauge to a intake manifold tap-like the one going to your map sensor-with the engine at normal idle, the gauge should show a nice steady needle somewhere between 16 and 22 inches on the dial face. It's a measure of inches of mercury if you understand science-most people don't so the dial face is very large and you just understand it as inches of vacuum-how much lower the air pressure is inside the intake, versus outside air pressure. All engines create manifold vacuum, and the best, newer engines have a very steady vacuum at idle of 21, or 22 inches on the gauge. That's what you look for, 16 and steady is okay, a good map sensor would be sending a good signal to the computer by a varied voltage signal: manifold pressure is known good, so to speak.
Now manifold pressure varies under different running conditions. But by looking at a vacuum gauge, you are confirming that your manifold vacuum is good, you have no vacuum leaks, no air or vacuum leaks anywhere that will upset the apple cart, and cause the computer to question the info from the map sensor.
If your vacuum reading is way below 16 inches, like 10 inches, or 12, or 14 and holding steady, well, don't you see, you have a major vacuum or air leak somewhere. Vacuum hoses, pcv hose, intake manifold gasket...somewhere, your engine is sucking in extra air, and it's causing havoc with the engine management controls. It's where a lot of poor running conditions occur. So, try a used or new map sensor, or buy a vacuum gauge for $20. It saves a lot of time looking for vacuum leaks, and it's also very good at detecting valve problems and other internal engine conditions. You just have to learn how to use it, and understand what it is telling you.
I think Dodge put the map sensor maybe on the firewall on the passenger side, not sure, it's been a lot of years ago.
Nov 19, 2013 |
1988 Dodge 600