Another HOT FUEL PUMP WIRE question
Another HOT FUEL PUMP WIRE question Today I went out to start the truck and it didn't prime on key on, little digging and I found the wire from the fuel pump relay burnt. I thought it must have grounded on something so I cut in a new male/female connector and went for a 10 minute drive. When I came back the fuel pump wire from the relay was very hot, like can't touch it hot.
Read a few posts on the topic but not super clear whats up beside the typical check grounds which I'll do in a minute but I wanted to toss this out there and see what you guys think before I dig in.
Have a standalone harness and built your typical Fuse/Relay setup for Main/Fan/Fuel pump found on the pcm pinout thread.
Here is the specifics:
Power to relay is thru a 30A fuse, the wire from Fuse to Relay is 12G and is wired into relay position 87
PCM Trigger is wired into relay position 86
Relay ground is wired into position 85, wire is 16G and shared with Fan relay ground
Power to Fuel pump is relay position 30 and is a 12G wire with a male connector
Fuel Pump wire is 12G and has a female connector and runs to the pump
What is interesting is the wire that runs to the pump is hot at the male/female connector but not far from that point it is fine.
The wire from the relay position 30 to the male/female connector is hot, the relay holder looks burnt at position 30 as well.
Could this be the pump ground, it is back near the tank and grounded on the frame.
What about a faulty relay, would that do this, thinking not so much.
Here is a pic of what I'm talking about, note I did not heat shrink the new male/female connectors, that happened on it's own!
https://photos.app.goo.gl/smLMfh1XJxWj7g3i7
Read a few posts on the topic but not super clear whats up beside the typical check grounds which I'll do in a minute but I wanted to toss this out there and see what you guys think before I dig in.
Have a standalone harness and built your typical Fuse/Relay setup for Main/Fan/Fuel pump found on the pcm pinout thread.
Here is the specifics:
Power to relay is thru a 30A fuse, the wire from Fuse to Relay is 12G and is wired into relay position 87
PCM Trigger is wired into relay position 86
Relay ground is wired into position 85, wire is 16G and shared with Fan relay ground
Power to Fuel pump is relay position 30 and is a 12G wire with a male connector
Fuel Pump wire is 12G and has a female connector and runs to the pump
What is interesting is the wire that runs to the pump is hot at the male/female connector but not far from that point it is fine.
The wire from the relay position 30 to the male/female connector is hot, the relay holder looks burnt at position 30 as well.
Could this be the pump ground, it is back near the tank and grounded on the frame.
What about a faulty relay, would that do this, thinking not so much.
Here is a pic of what I'm talking about, note I did not heat shrink the new male/female connectors, that happened on it's own!
https://photos.app.goo.gl/smLMfh1XJxWj7g3i7
Last edited by epfatboy; Jul 28, 2020 at 08:07 PM.
I checked the grounds and they are fine, bare metal, tight, no signs of wear and tear.
The male/female connections in the picture are heat shrinks the I didn't apply heat to before I took it for a test drive. You can see how hot the relay side of the connection point was versus the pump side of the connection point since the relay side was hot enough to shrink the connection and the pump side connection remained un-shrunk.
https://photos.app.goo.gl/DRcr58KwmjECKcAn8
I used the same config for the fan, it's male/female connection is fine. You can see those in the pic too.
Wondering if I should cut the male/female connections out and tie the wire together for my first test I'll probably replace the wire from the relay side as well since it has been clearly over heated a few times.
I'll replace the relay too. That might mean I don't figure out why this happened but I might as well just knock it off while I'm in there and move on.... I hope.
The male/female connections in the picture are heat shrinks the I didn't apply heat to before I took it for a test drive. You can see how hot the relay side of the connection point was versus the pump side of the connection point since the relay side was hot enough to shrink the connection and the pump side connection remained un-shrunk.
https://photos.app.goo.gl/DRcr58KwmjECKcAn8
I used the same config for the fan, it's male/female connection is fine. You can see those in the pic too.
Wondering if I should cut the male/female connections out and tie the wire together for my first test I'll probably replace the wire from the relay side as well since it has been clearly over heated a few times.
I'll replace the relay too. That might mean I don't figure out why this happened but I might as well just knock it off while I'm in there and move on.... I hope.
Ditch those cheapo connectors.
Appears that the crimp on the red wire is funky, creating a high resistance connection.
That huge stack of wires, crimp ons, isn't helping, either.
Appears that the crimp on the red wire is funky, creating a high resistance connection.
That huge stack of wires, crimp ons, isn't helping, either.
Thanks geezer, I plan to rebuild the entire electrical system at some point after I get thru tuning this thing. This was my first standalone harness and I followed the guide provided in the pinout threads, including building this block so that I didn't run into problems.
I'm certain that male/female connection is the problem but wanted this to be a "good enough" one and done repair so I swapped out the relay holder, the relay, relay to fuel pump supply wire, swapped pos 30 and 87(had them backwards not sure that mattered), and dumped the male/female 16-14 connector for a 12-10 butt connector. I know the time tested model is wire tie and solder but for now this will have to do.
Took her for the same test ride as I did yesterday and the wire is not hot or warm. I'm still tuning this config (first time HPT Tuner) so I'll take her out for a few runs as I keep making tune adjustments and monitor the wires.
I did note the male/female connector was a 14-16G connector not a 12-10, that might be where the problem was so while I was at it I also cut out the male/female 14-16 connectors for the FAN supply wire and replaced it with a 12-10 butt connector too.
Question if connectors are used by some is there a preferred brand? I do try to buy quality and I had thought these were pretty good but I'm always looking for something better. FYI these connectors are from wirefy.
I'm certain that male/female connection is the problem but wanted this to be a "good enough" one and done repair so I swapped out the relay holder, the relay, relay to fuel pump supply wire, swapped pos 30 and 87(had them backwards not sure that mattered), and dumped the male/female 16-14 connector for a 12-10 butt connector. I know the time tested model is wire tie and solder but for now this will have to do.
Took her for the same test ride as I did yesterday and the wire is not hot or warm. I'm still tuning this config (first time HPT Tuner) so I'll take her out for a few runs as I keep making tune adjustments and monitor the wires.
I did note the male/female connector was a 14-16G connector not a 12-10, that might be where the problem was so while I was at it I also cut out the male/female 14-16 connectors for the FAN supply wire and replaced it with a 12-10 butt connector too.
Question if connectors are used by some is there a preferred brand? I do try to buy quality and I had thought these were pretty good but I'm always looking for something better. FYI these connectors are from wirefy.
"Thanks geezer, I plan to rebuild the entire electrical system at some point after I get thru tuning this thing. This was my first standalone harness and I followed the guide provided in the pinout threads, including building this block so that I didn't run into problems."
Suggest you reverse your schedule, and do the rewire before the tune up....
Suggest you reverse your schedule, and do the rewire before the tune up....
