MattHDSM
5+ Year Contributor
- 113
- 71
- Oct 20, 2018
-
Ottawa,
ON_Canada
Hey there DSMers, I've run into an intermittent no start condition which I believe I have pin-pointed down to the MAP sensor. It's a mitsu style Omni 4 bar, about 3-4 years old by now. I have checked timing, spark, and fuel. Didn't get the chance to check compression before I killed the battery, but it randomly ran fine yesterday after getting towed back home, so I'm going to make the (unwise) assumption and say compression is good without checking. The no start is when I turn the car over, it "fires" once and immediately dies.
Today, I noticed in my logs that the sensor is reading -28.9 inHg of vaccuum with the car off and while cranking. If I apply pressure to the top of the sensor, it reads 0.1 psi which makes sense given the car isn't running and sitting at atmospheric pressure. Unfortunately for me, I don't have a second pair of hands around to test cranking while applying pressure to the sensor.
I'm new to running speed density so my question to you guys is if the following makes any logical sense. I turn the car over, it "fires" once and immediately dies because the MAP sensor is reading no pressure. No pressure means the ecu thinks there is no air and doesn't send any fuel. No fuel, no bang, car dies.
Please let me know what you think, Thanks.
Today, I noticed in my logs that the sensor is reading -28.9 inHg of vaccuum with the car off and while cranking. If I apply pressure to the top of the sensor, it reads 0.1 psi which makes sense given the car isn't running and sitting at atmospheric pressure. Unfortunately for me, I don't have a second pair of hands around to test cranking while applying pressure to the sensor.
I'm new to running speed density so my question to you guys is if the following makes any logical sense. I turn the car over, it "fires" once and immediately dies because the MAP sensor is reading no pressure. No pressure means the ecu thinks there is no air and doesn't send any fuel. No fuel, no bang, car dies.
Please let me know what you think, Thanks.