bumblebeer
Registered User
I finally managed to fix all my fuel leaks, but I'm still dealing with an air intrusion issue. After sitting for a while, usually overnight, she starts and then dies after a couple of seconds. Then I have to crank for a while to get it started again. Afterwards it runs rough for a minute, then settles down and runs just fine for the rest of for the day. Classic air intrusion / fuel drain back issue. The correct thing to do would be to chase down the problem and fix it. But... I don't have any actual fuel leaks, and other than the rough starting, it runs just fine. And I'm planning to do a WVO conversion on this rig when winter come around. I'll take the time to actually track down and fix the issue at that point, but in the meantime, I wanted to do something to prevent the starting trouble.
I know some folks will run an electric fuel pump in parallel with the mechanical pump and run it to a momentary switch in the cab. But I didn't like the idea of running a switch, drilling the dash, etc, just for a temporary hack. So I present to you "The Auto-Magically Self-Priming Fuel System Hack"
Electrical diagram on left, fuel diagram on right.
I put a cheap ~$20 fuel pump in line with the mechanical pump with a couple of check valves to control flow. Then, instead of running a switch to the cab, I pigtailed a relay. Fed the hot for the control from the ignition switch lead on top of the GP relay, and then grounded it out to the control terminal on the GP relay where the white wire is connected. Pulled hot for the pump from the hot side of the starter relay and used an inline fuse. Grounded the pump out to the passenger fender. Zip tied the relay and everything together on top of the passenger wheel well. If you wanted a cleaner or more permanent install, I reckon you could use a spare relay slot in your fuse box.
Connected like this, the electric fuel pump only runs when the glow plugs are running. Works like a hot damn! If the engine is cool enough to need to run the glow plugs, then it may have lost prime, so you'd probably want to run the prime pump. The cooler the engine, the longer the pump runs. If the engine is hot enough not to need the plugs, then it probably hasn't lost prime, so no need to run the pump. Once the wait to start light (glow plugs) turns off so does the electric pump, and you're good to start.
Basically you're only running the prime pump when you'd most likely need it, and running it proportionally to how much air may be in the fuel system. And it's turning off before the mechanical pump takes over. And it's all being done automatically.
The only time I could see there being an issue is if you have a serious leak back issue, or if the truck sits for an extended period of time. Then the electric pump may not run long enough to restore prime, but in that case you could just cycle the glow plugs a couple of times.
Anyway, figured I'd share what I thought was a pretty neat hack. Cheers y'all!
I know some folks will run an electric fuel pump in parallel with the mechanical pump and run it to a momentary switch in the cab. But I didn't like the idea of running a switch, drilling the dash, etc, just for a temporary hack. So I present to you "The Auto-Magically Self-Priming Fuel System Hack"
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Electrical diagram on left, fuel diagram on right.
I put a cheap ~$20 fuel pump in line with the mechanical pump with a couple of check valves to control flow. Then, instead of running a switch to the cab, I pigtailed a relay. Fed the hot for the control from the ignition switch lead on top of the GP relay, and then grounded it out to the control terminal on the GP relay where the white wire is connected. Pulled hot for the pump from the hot side of the starter relay and used an inline fuse. Grounded the pump out to the passenger fender. Zip tied the relay and everything together on top of the passenger wheel well. If you wanted a cleaner or more permanent install, I reckon you could use a spare relay slot in your fuse box.
Connected like this, the electric fuel pump only runs when the glow plugs are running. Works like a hot damn! If the engine is cool enough to need to run the glow plugs, then it may have lost prime, so you'd probably want to run the prime pump. The cooler the engine, the longer the pump runs. If the engine is hot enough not to need the plugs, then it probably hasn't lost prime, so no need to run the pump. Once the wait to start light (glow plugs) turns off so does the electric pump, and you're good to start.
Basically you're only running the prime pump when you'd most likely need it, and running it proportionally to how much air may be in the fuel system. And it's turning off before the mechanical pump takes over. And it's all being done automatically.
The only time I could see there being an issue is if you have a serious leak back issue, or if the truck sits for an extended period of time. Then the electric pump may not run long enough to restore prime, but in that case you could just cycle the glow plugs a couple of times.Anyway, figured I'd share what I thought was a pretty neat hack. Cheers y'all!
