Map sensor bad?


New Member
Dec 18, 2003
Im not sure what the problem is, but with my 3-bar MAP sensor exposed to vacuum of the motor the car begins to surge extremely bad and is impossible to keep at a steady rpm. But when I remove vacuum from the sensor, the car idles like a dream, revs great, etc.. Just wondering if the sensor maybe is bad or do I need to do some number work in the tables?
are you running a factory ecu or aftermarket.

If you are running the fast system, you can turn the key to the on position (not running) pull up your dashboard and look at the map reading. It should be about 100-104 for a 1 bar map. I would think it would be the same for a 3 bar map since it is reading ambiant air pressure.

Did you make sure that the vacuum line was not cracked creating a leak?
lol that would help its a fast bank to bank system. No the vacuum line is not cracked because when I remove it from the map sensor i just plug it off so the line is still connected to the engine vacuum...
That makes absolutely no sense. What you are saying is your car idles and revs great with fueling stuck at 0 RPM and 98 kpa map conditions, which is all the VE map is looking at when you disconnect the vac line from the map sensor.

Is this a brand new install? I would look at my VE screen when it is hooked up and when it is not hooked up to make sure readings make sense.