Can anyone tell me what is the destination in the engine wiring harness of the wires that connect to pins D3 and D10 in the 165 ECM (87-88 TPI 350)? The diagram say they are grounds but I need to know if there are wires there where they end. I have an application which doesn't have does wires and grounding them to chassis causes major flooding and I suspect that may be my problem. Thanks.

 

{edited out a CSH moment. . .}

RBob.

 

The ECM connector that I'm using didn't have those wires. If I add them (which I did) to what I need to connect them? To D1 wire?
I saw an ECM diagram that shows D1, D3 and D10 as same circuit. I connected them to D1 and problem seems the same...

 

Wow, did I ever mess up, someone, please pass me a CSH. . .

The pins you listed (D1, D3, & D10) do indeed get connected to ground on the engine block.

The injector driver pins are D15 & D16, which is what I thought D3 & D10 were.

You mentioned connecting ECM grounds to the chassis. Every GM ECM setup I've seen only has the grounds going to the engine block.

As for your original problem, the flooding, check that the ECM injector drivers are not shorted out. IOW, bad.

RBob.

 

Here is a chart that shows the Pin and circuit that it goes to for the 165 ECM in V8 F-body cars.

Hope it helps

 

They ground to the back of the right cylinder head along with the braided ground strap that connects to the firewall on the passenger side.

 

Rob, you got me very confused momentarily. That's ok
I need to recheck all these grounds and injector lines again. This engine is dumping so much fuel that it almost gets liquid to the muffler tips

Thanks to all!

 

To help troubleshoot the problem unplug all of the injectors. Then place a light bulb such as a dash or taillight bulb in place of one injector.

Can then use this to tell if the injectors would be on or off. At key on the bulb should be off. Then during crank it should blink on once per revolution.

RBob.

 

I did that but at key on bulb is on. ECM diagram (see pic above) shows that at key on it should show 12V. ?? I have 12V at boyj pins with key on. I thought that it throws one pin to ground to turn on injector. Now I'm confused...

 

Does the bulb stay lit if you unplug the ecm from the circuit?

If it goes out when the ecm is unplugged it sounds like the driver in the ecm is shorted to ground.

With the injectors plugged in there should be 12 volts at the ecm connector in the KOEO (Key On Engine Off) position due to the current flow from the battery to the ecm.

 

Correct, ECM pulls pins D15 & D16 to ground to enable the injectors. Both pins go to a single driver in the ECM.

What Eric said, unplug the ECM, if the light goes out the ECM is bad. If the light stays on, then one of the wires (D15 & D16) is pinched and is grounded out.

RBob.