MAP sensor voltage Spikes

EMU PRO
1

So my car developed an issue recently where my MAP sensor starts to see voltage spikes up and down, usualy during WOT runs. Due to wrong voltage and map value it is expected hat it runs very rich and it becomes undrivable.

When it happened first time It tokk me some time till I understood what is the issue and in order to mitigate it I tried and removed the MAP sensor connector (with ignition swithced off), inspected the wires and connector and pluged it back in and on the next engine start the car started and drove like nothing happened.

Recently it started to do this more often and the same fix works but the issue is still there.

The MAP sensor is a RIFE 5bar with Deutch connector.

Also recently tried to plug the Dragy USB A cable to charge it from the USB flash drive port and the MAP sensor voltage spike happened instantly.

I repeated same test several times and was able to reproduce the behavior.

I am a bit confused on what could be the issue. Please help with suggestions on how to identify the root cause for that.

Initialy I though that maybe the wiring of the USB-A might be shorted and I disconnected the USB-A port and I checkced the Powe 5v and Ground for continuity and found out that indeed it was shorted, I then removed the connector B (where flash drive power and signal pins are located) and I tried to check once again for continuity which disappeared alraedy. I plugged back the connector and checked onc again on the USB-A side and there was still no continuity.

Can those 5v and Gnd line be shorted inside the ECU?? What would be the correct way to diagnose this issue?

Sorry for long read, I tried to share as much details as I could.

Bellow some log screns example on how it happens

Voltage spike UP during IDLE and usb-a connected

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Voltage spike down after a run

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2

Is 100 Kpa your failsafe value ? that means map sensor makes intermittent connection with the ecu for some reason or another and you get failsafe value …

3

Yes 100 is the fail safe value that could be set on connection loss, but this does not explain the 400kpa at Idle issue.

4

I could be a connection loss as well, but on the ground pin. If you disconnect the ground from the sensor, it would behave like a pull-up resistor.

You can observe the measured voltage of the 5V source on channel ECU / 5V source A and B to check if everything is okay with it. I recommend to increase the logging frequency for the channels you watch during diagnosis.

Did you use multimeter probes for measurements on the connectors? Perhaps this stretched the pins out. Have you checked the 5 V and GND splices?