ECM trouble shoot
 

Just got power to the car all is good except the ECM. The red mil light is on in the fuse panel relay, I do not have power to the fuel pump , the yellow mil light does not come on and I will check the codes this week. There is power to the ECM and all the fuses look fine, not sure about the relay, the harness is new and this is the first time power has been to it. I have the fuel pump wire from the ECM going to an on/off switch. Any ideas
https://lateral-g.net/forums/showthread.php4?t=44704

Why do you have the pump wire from the ECM going to a switch? It should go to the pump relay.

When you 1st turn the key on the ECM will pulse the fuel pump for a few seconds then stop. When the engine starts the ECM will control the fuel pump.

Perhaps the switch is an anti-theft feature?

Here is the update. I have the Holley electric fuel pump. The directions for the ECM said to take the power supply wire for the fuel pump and attach it directly to the power wire on the pump. I have it going to a 40 amp switch. Right now there is no power going to the fuel pump wire. The little red light is on in the fuse relay panel but all the fuses are good. When I pull the ignition relay out the red light goes away and the MAF shutters for a second. When I try other relay's the same effect occurs. I have zero codes.

I have run power to the pump and it works. :drowninga: Thanks


https://lateral-g.net/forums/showthread.php4?t=44704

Looking for a life raft here, thanks. Its got to be simple

Post a schematic/diagram of what you have connected. Hard to follow otherwise.

Don

Key engine not running there will not be 12V to the fuel pump

So there will not be 12 volts there unless its running? I would think there would be a short 2 sec burst on the initial turn of the key?

yes short burst when key is 1st turned on

thanks I will check tonight