VETTE_50_TH
Banned Member
- 3,733
- 22
- Jun 24, 2004
-
Columbus,
Ohio
Ok. Ill start from the beginning. We took out the old harness and replaced it with a harness we removed all the unnecessary plugs from. We removed them directly and fully de-pinned the ecu plugs. We also rewired the fuel pump and relocated the battery to the back.
Now, we go to start the car because we finally finished the engine bay and we dont get any fuel. We find that I didnt rewire the ground correctly. Fix that. Nothing. We find that the car isnt sparking. We found a ground we missed and still nothing. We think it might be the mpi/fuel pump relays. Nada. All checks out.
Then we find that the ecu is only getting 2.7V at pin 12 and 25, but the rest of the car is getting the 12V from the battery, including the backup power for the ecu, fuel pump, etc.
This is also where it gets confusing. The car starts when we jump the relay and the ecu finally kicks on. We are jumping pin 38 which is the MPI relay control. We know this because we get the CEL like we are suppose to. Then we can start the car. Next, we try to connect evoscan to the car, but it says less than 5V, cannot connect. That data pin is pin 62.
Finally, we realize that all these pins we are having trouble with go directly to the chassis harness under the dash. What is up there that could be causing this.
The way the owner before i had fixed this is by using another relay between the two mpi and fuel relays. Thats how he was able to jump the car. Im guessing the car has a bad ground up there or something because the ecu is getting some power. Just not enough.
Please give me any thoughts or recommendations.
Now, we go to start the car because we finally finished the engine bay and we dont get any fuel. We find that I didnt rewire the ground correctly. Fix that. Nothing. We find that the car isnt sparking. We found a ground we missed and still nothing. We think it might be the mpi/fuel pump relays. Nada. All checks out.
Then we find that the ecu is only getting 2.7V at pin 12 and 25, but the rest of the car is getting the 12V from the battery, including the backup power for the ecu, fuel pump, etc.
This is also where it gets confusing. The car starts when we jump the relay and the ecu finally kicks on. We are jumping pin 38 which is the MPI relay control. We know this because we get the CEL like we are suppose to. Then we can start the car. Next, we try to connect evoscan to the car, but it says less than 5V, cannot connect. That data pin is pin 62.
Finally, we realize that all these pins we are having trouble with go directly to the chassis harness under the dash. What is up there that could be causing this.
The way the owner before i had fixed this is by using another relay between the two mpi and fuel relays. Thats how he was able to jump the car. Im guessing the car has a bad ground up there or something because the ecu is getting some power. Just not enough.
Please give me any thoughts or recommendations.