So, I have been having an issue with the fuel pump circuit on my 1993 K1500 and I am hoping that you guys may have some ideas that I haven't had yet.
About two months ago I began having an issue where my truck would randomly cut off while I was driving down the road and then not start back. When this would happen the fuel pump was not coming on so I figured it must be bad since I was getting no codes. Swapped it out and the truck seemed to run fine.... for a while. Now it is doing the same thing again but it will not stay running very long at all now (maybe 2-3 minutes if I'm lucky). I then began trying to diagnose what was wrong and found that I was getting power to the fuel pump relay. When the truck runs I am getting power to the 20A fuse and hence through the fuel pump relay. When the truck shuts off, it immediately clicks and there is no power through the relay or fuses. I checked for power at the oil pressure switch and have power there. I figured it must be one of these switches so I replaced both. Still nothing.... same old story. I would check for power at the pump but since I'm not getting it through at the relay I know I don't have it at the pump. I jumped the relay (orange to gray) and got power back through the relay and hence to the pump. The truck still won't start. I checked the 10A fuse on the fuse block under the dash and found that it has proper resistance. I also swapped it out with my brake fuse just for giggles and still have the same old thing.
In all of this, I am not getting a code except when I have the ALDL jumped out to read the codes and try to start it. I then get a code 54 which makes me think that my issue is simply that I am not getting proper power signal to the ECM. My question would be how can I test this? Could it possibly be an ignition issue and if so, how do I test this? I don't particularly want to just keep throwing parts at the issue especially since my wife is becoming a bit pissy about the whole "Just one more part... I hope" conversation.
Any help is appreciated.
About two months ago I began having an issue where my truck would randomly cut off while I was driving down the road and then not start back. When this would happen the fuel pump was not coming on so I figured it must be bad since I was getting no codes. Swapped it out and the truck seemed to run fine.... for a while. Now it is doing the same thing again but it will not stay running very long at all now (maybe 2-3 minutes if I'm lucky). I then began trying to diagnose what was wrong and found that I was getting power to the fuel pump relay. When the truck runs I am getting power to the 20A fuse and hence through the fuel pump relay. When the truck shuts off, it immediately clicks and there is no power through the relay or fuses. I checked for power at the oil pressure switch and have power there. I figured it must be one of these switches so I replaced both. Still nothing.... same old story. I would check for power at the pump but since I'm not getting it through at the relay I know I don't have it at the pump. I jumped the relay (orange to gray) and got power back through the relay and hence to the pump. The truck still won't start. I checked the 10A fuse on the fuse block under the dash and found that it has proper resistance. I also swapped it out with my brake fuse just for giggles and still have the same old thing.
In all of this, I am not getting a code except when I have the ALDL jumped out to read the codes and try to start it. I then get a code 54 which makes me think that my issue is simply that I am not getting proper power signal to the ECM. My question would be how can I test this? Could it possibly be an ignition issue and if so, how do I test this? I don't particularly want to just keep throwing parts at the issue especially since my wife is becoming a bit pissy about the whole "Just one more part... I hope" conversation.
Any help is appreciated.
