MAP Sensor malfunction
 

Hi,
I have an issue with my car not starting. When on ignition Wastegate and pre-control solenoids are clicking.
My PFC is showing almost 5V on PIM, but when I was moving ECU around it drops a bit. I checked continuity from Map sensor to ECU Pin and it is ok. Is there something else to check before going through whole harness?

https://cimg7.ibsrv.net/gimg/www.rx7...bce9dd862.jpeg

that reading would indicate an "open".... which could also be translated as no reading. if you unplug any of the other sensors it will show the same value for that sensor. its possible your map sensor has failed.

if you say the reading changes some when you move the ecu around then you may have an obvious issue there. i would advise replace the map sensor with a good one before chasing wires. start with the easier thing

I wouldn't trust the multimeter's continuity check when troubleshooting harness problems, I would measure resistance between the ECU and the sensor. If you suspect something is intermittent or a poor connection, try tapping or shaking or gently bending the harness while watching resistance. The resistance of the wire should be very low, less than 1 ohm. And the measured resistance shouldn't change when the harness is tapped or moved or shaken.

If your testing shows the sensor wire is good, I would check the sensor's ground wire next, it should show connection to one of the ground pins on the ECU or to the chassis ground. I don't remember exactly which ground connection that branch of the harness uses, but the factory wiring diagram should show it.

Change the MAP sensor. I had the same issue once before. The car would not start and I heard a clicking noise from the WG solenoid when the key was in the on position. I swapped out the MAP for a new one and everything was fine. I am not sure why my MAP went bad though. The car was down for a few months due to some other issues, but nothing that should have affected the MAP sensor. Oh well!

I decided to go with the trail of value changing while moving ECU around. There is this X-05/X-07(don’t remember exactly or it is called differently on Series 8) connector in passenger footwell. Apparently ground coming from one harness(BR/B) to another(B/GR) was loose on BR/B side. While moving it around, read PIM voltage was changing. I pulled out those wires from connector, connected them aside and seems to be working now.