Pontiac electrical problem
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
Pontiac electrical problem I am having a problem with my electrical system. Namely, I am only getting 9V of ignition switched power at the ECU. I am swapping a LS1/t56 into a '68 GTO.
I was told to check the black bulkhead electrical connector because it often gets gummed up with the grease that was originally used to prevent the pins from corroding. It was dirty, so I cleaned it out good, but still no improvement. I checked the battery: 12V. I also checked the voltage across the key switch, 12V there, too, so I know that is not the problem.
There is 1.5 ohms of resistance between the ECU and the battery terminal when the key is in the 'on' position. I want to say that whatever is wrong must be between the key switch and the bulkhead connector, but with such little resistance I am not sure what could possibly be the matter. Does anyone have an idea of something to investigate next?
I was told to check the black bulkhead electrical connector because it often gets gummed up with the grease that was originally used to prevent the pins from corroding. It was dirty, so I cleaned it out good, but still no improvement. I checked the battery: 12V. I also checked the voltage across the key switch, 12V there, too, so I know that is not the problem.
There is 1.5 ohms of resistance between the ECU and the battery terminal when the key is in the 'on' position. I want to say that whatever is wrong must be between the key switch and the bulkhead connector, but with such little resistance I am not sure what could possibly be the matter. Does anyone have an idea of something to investigate next?
That's a tough one. Are you certain that you have 12v coming out of the ignition switch? Are you sure you're testing the correct wire?
Are you using a digital or analog multimeter?
Are you using a digital or analog multimeter?
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
I am sure I tested voltage across the switch. I also completely remove the switch and tested resistance across it. I know I have the correct pins because they are labelled on the back of the switch.
I am using a digital multimeter.
I am using a digital multimeter.
Launching!
Joined: Jun 2009
Posts: 213
Likes: 3
From: Manitowoc wi.
Have you checked your ecm grounds? Remove the connector at the ecm and recheck your voltage at the correct pin to battery negative. Then check your voltage again from that same pin to the ecm ground pins to determine if you have readings within .5 volts of each other. if not correct the grounds for the ecm or still better yet run the ecm grounds directly to the battery negative.
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
I believe that I have determined my problem. I used the wire that used to supply the distributor to supply switched voltage to my ECU. This wire has an internal resistance to step the voltage down to 6V. If I replace this wire I should be in good shape.
Next problem...does anyone know how to de-pin this coupler?
Next problem...does anyone know how to de-pin this coupler?
