ECM (ECU) ground wires (E1 & E2, GR/BK) floating!

[podling]

My '93 1.0 liter would not start; no spark or fuel pump sound. Turns out the ground reference leads of the ECM (E1 and E2, GR/BK and BK/GR) were floating, so I'm not sure the ECM was even running. These lines are not grounded to the frame within the ECU, so they must be grounded at some point external to it. However, a close inspection of the fuse panel revealed no wires coded thusly. As a temporary fix, I connected these lines to the frame internal to the ECU.

Anyone know where the GR/BK and BK/GR wires are grounded to the chassis?

[Crvett69]

not sure if its the same wires but there are 2 or 3 ground wires that bolt to the intake and if they are not connected you lose spark and fuel

[spy1309]

Corvette is right there are 2 ground wires conected to the Intake manifold in the back of the TBI on the lower left side when you face the engine ( just above of the starter ).

[podling]

Thanks guys! I found the two wire ground ring terminal that I neglected to reconnect after working on the head. Without it the +5 volt sensor reference floats to B+ and no spark or fuel pump.