68Problemchild

iTrader: (1)

Having trouble with the injectors firing on my L92. What is the proper attachment of grounds?

One large neg to each head?

I have two to engine (one on drivers head rear), one to body, one to frame.

chevyboy91188

iTrader: (15)

shouldnt need a ground to the heads? the ground for the injectors are through the ecm so make sure that the computer is grounded good, i ran one straight to the negative battery terminal for my comp as well as to the body/frame just for good measure.

and where are you in swfl?

68Problemchild

iTrader: (1)

Bonita springs. You actually ground the ecm box itself?

gofastwclass

iTrader: (2)

Not the box itself. There will be ground wires on the PCM (ECM / PCM / VCM, depends on who you talk to) pinout that need to be grounded. Most run to sensors or somewhere on the engine but a few are for the PCM itself.

Injectors have their own circuit and it is powered by two of the pink wires. They are fired by completing the ground to the injectors through the PCM.

chevyboy91188

iTrader: (15)

x2 there should be pinouts for ground.

and you're pretty far into sw Florida from me lol, thought you might be a little closer haha

rsz288

Factory harnesses generally ground to each head. GM most/always uses one for each head. They are common'd in the harness. This runs the engine ground requirements back through the engine which is grounded to the battery.

The ECM has a single ground which, if it is not grounded back through to the engine ground can be grounded to chassis or engine. Just important that the chassis is well grounded to engine or battery. The ECM case is internally grounded. The coils are grounded to the engine but the injectors as noted run 12V on one side and the ECM grounds the other side of the injector to pulse them.

Depends on what layout your harness manufacturer used. It would be in the instructions.

Fingers crossed it isnt grounds that is causing your start challenges.