Resolved 1G ECU ground/ECU boots intermittent

[Brian Drake]

Just want to make sure I'm looking at the right thing. The ecu ground is on the passenger side of the center console right below where the mpi relay mounts correct

 

[steve]

If I remember correctly, yes. You should be able to trace it back to the pins on the ECU connector.

What is the issue you're chasing?

 

[Brian Drake]

my ecu dropped out. cel light stayed on and boost gauge did not center. was recently socketed and refurbed by ecmtuning so i was thinking i might have a grounding issue causing it not to power up.

 

[steve]

You can check by measuring from the ground pins on the ECU connector to the chassis. It should be a direct short if the connection is good.

 

[Brian Drake]

I checked them with a multimeter and traced them about a ft up the harness. The Ground under the passenger dash speaker at the center were good but I had intermittent continuity one of the ecu grounds. I tapped into the grounds and ran new ones to the center.

 

[steve]

ECU starting up fine now?

 

[Brian Drake]

f*** no. Worked for about a week then started to boot intermittent again. Pulled pins 102 107 103 101 106 and expanded the tabs for solid connection. Has good ground on dvom. Pulls mpi relay closed have power at 102 107 103 and switched power at 110. Ecu looks immaculate. New caps from ecm tuning and socket from po and don't see any signs of damage or corrosion. Cleaned it with deoxit g5 then crc qd for good measure. Boost gauge went to zero and cel went off after 5 seconds 5 or 6 times after plugging it back in then nothing.

 

[Brian Drake]

Got home from work after letting the ecu sit plugged in for about 2 hours. Ecu booted. Isc reset and then it dropped out.

 

[Brian Drake]

Images of the ecu

 

[steve]

How does it behave when it dies? Is it like it reboots or like the ignition switch got turned off?

Have you monitored the voltages to the ECU and MPI relay?

 

[Brian Drake]

Boost gauge dropped dead. Engine stopped when car was running like it would if you turned the key off but ecu still had power across the board. I checked voltages at the inside of the ecu from the backside of the connector. Voltages matched battery 12.6v and held constant.

 

[Brian Drake]

Managed to find a 91 non eeprom turbo ecu at my local pick and pull that was in great shape. Plugged it in turned the key booted right up. Problem is Def with my ecu. Guess it's going back to ecmtuning

 

[Brian Drake]

Just heard back from ecmtuning. The link chip failed internally some how. They replaced it and it should be good to go.