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HI Guys,
Have a very strange issue that's been around for a few years and no shops seem to be able to reliably fix the issue. The problem is related to the map sensor - it intermittently will not read correctly. The sensor will read anywhere from 30 - 100 rather than stay steady at 100 with the key on and motor off. The range and randomness of the reading seems to vary, and the shop was able to test the voltage by removing the condenser and checking - the voltage from the EMM/ECU is also random and not fixed at ~5 volts when the problem is occurring. The sensor is still technically connected as they added a plug for the condenser. No other 5 volt sensors are affected and never have been to our knowledge. The strangest thing is that the problem randomly disappears (more on that later). The symptoms are the motor will stumble, occasionally stall and/or not start, and it cannot be revved up. The problem was initially solved by replacing the harness - they first tried a new MAP / Intake Air pressure sensor and it didn't do anything. Apparently they had seen it once before and a new harness solved the problem for years. The shop thought it was related to the 'condenser' (resistor/capacitor pack in between the ecu and the sensor). Unfortunately, the problem resurfaced after a few months and they have made their own 'condensers' and the problem went away for a few months at a time again. Now it is back and new condensers aren't helping- the problem seems to fix and unfix itself randomly. At one point removing the condenser made the problem disappear and the signals stabilized at ~5v in and ~4v out with the motor off, but that has stopped . They've tested many components to no avail: swapped EMM/ECUs, isolated the port battery from all house systems, tested for shorts to ground, and changed intake pressure sensors. The strangest thing is that the problem can be observed intermittently and will simply go away with no changes after anywhere from a few minutes to a few hours. So we're at a bit of a loss - we thought perhaps a house system from the boat was causing it but after isolating the problem is returning and we have replaced every component that is involved with the intake pressure sensor. Is there anyone who has seen this problem or can point us in the right direction for a diagnosis? Thanks for any input!
Have a very strange issue that's been around for a few years and no shops seem to be able to reliably fix the issue. The problem is related to the map sensor - it intermittently will not read correctly. The sensor will read anywhere from 30 - 100 rather than stay steady at 100 with the key on and motor off. The range and randomness of the reading seems to vary, and the shop was able to test the voltage by removing the condenser and checking - the voltage from the EMM/ECU is also random and not fixed at ~5 volts when the problem is occurring. The sensor is still technically connected as they added a plug for the condenser. No other 5 volt sensors are affected and never have been to our knowledge. The strangest thing is that the problem randomly disappears (more on that later). The symptoms are the motor will stumble, occasionally stall and/or not start, and it cannot be revved up. The problem was initially solved by replacing the harness - they first tried a new MAP / Intake Air pressure sensor and it didn't do anything. Apparently they had seen it once before and a new harness solved the problem for years. The shop thought it was related to the 'condenser' (resistor/capacitor pack in between the ecu and the sensor). Unfortunately, the problem resurfaced after a few months and they have made their own 'condensers' and the problem went away for a few months at a time again. Now it is back and new condensers aren't helping- the problem seems to fix and unfix itself randomly. At one point removing the condenser made the problem disappear and the signals stabilized at ~5v in and ~4v out with the motor off, but that has stopped . They've tested many components to no avail: swapped EMM/ECUs, isolated the port battery from all house systems, tested for shorts to ground, and changed intake pressure sensors. The strangest thing is that the problem can be observed intermittently and will simply go away with no changes after anywhere from a few minutes to a few hours. So we're at a bit of a loss - we thought perhaps a house system from the boat was causing it but after isolating the problem is returning and we have replaced every component that is involved with the intake pressure sensor. Is there anyone who has seen this problem or can point us in the right direction for a diagnosis? Thanks for any input!
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