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geoff650
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Last seen: 1 year 9 months ago
Joined: 08/02/2015 - 10:01
Possible MAP Sensor Problem?

So I have come across a mysterious idle issue on my car. My car is on your Infinity 8 with your 5 bar map sensor. I have checked for any type of leaks exhaust and boost and didn't find anything. I have replaced one map sensor already back in March of this year due to where it was mounted. I now have it mounted with a new sensor in an area with much less vibration and driveability appears to be ok, however idle is very inconsistent and the car wants to die when pulling it around a parking lot at low speeds. Also while idling the car stumbles and the afr goes rich randomly and it does this a few times. It was never doing this before so I am kind of stumped as to whats going on. Should I post an idle log that I took yesterday? Also would it be a good idea to do the map sensor test for voltage to see if it falls within range according to your chart? And maybe hook the car up with shop air and pressurize the system a little bit to see if the map sensor is reading the same as the gauge we use to fill the system? I have also noticed cruising afrs seem to go rich every so often but it might just be the afr changing due to my throttle position. Any input would be great and I will do whatever tests I need to do on my end to resolve the issue. 

geoff650
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Last seen: 1 year 9 months ago
Joined: 08/02/2015 - 10:01
Upon further diagnosis the

Upon further diagnosis the car didn't want to fire up tonight. Can a faulty map sensor cause this to happen? Seems like it takes longer to start as well. Battery is new and voltage is good. Also the map sensor was reading 1 psi with the car off. Does this mean its defective? It is definitely mounted in a position with less vibration so I am a little stumped as to why this keeps happening. 

AEM_SB
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Last seen: 1 week 21 hours ago
Joined: 06/07/2014 - 14:29
Yes, please post logs if you

Yes, please post logs if you have them. Please make sure the logs also include Battery Voltage, Air Temp, Coolant Temp, Throttle, and any other temperature or pressure sensors that are installed. Many of the sensors receive 5V or ground from the same ECU pins, so it's very useful to know if a problem is isolated to one sensor or if it's present on other signals as well.

Intermittent wiring problems can make the vehicle behave similar to malfunctioning sensor, if the problem seems to occur more often when there is a lot of chassis or engine movement due to shifting gears or bumpy / rough spots on the tracetrack that can be a good indicator that some wires are shorting or losing connection due to vibration.

 

Hope that helps,

SB

geoff650
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Last seen: 1 year 9 months ago
Joined: 08/02/2015 - 10:01
I replaced the map sensor and

I replaced the map sensor and the car appears to be running back to normal. I will probably send in the old map sensor to have it checked out and see if its still functioning properly.