External fuel pumps overheating?
Thread Starter
Teching In
Joined: Nov 2014
Posts: 9
Likes: 0
From: Kansas
External fuel pumps overheating? Got a bit of an issue my friend and I can not figure out. Got a lq9 swaped into an Apache. He is using a 70's mustang fuel tank and an external fuel pump. After about 20 min or so the pumps get hot and fuel pressure goes down so much it won't run. He has tried 3 different external pumps and its the same issue each time. Even tried running wires straight from the battery to see if that was where the issue was coming from. No dice.
We are stumped as what this could be. Any help would be helpful. Thanks. Here is a pic of the setup as it is right now.
We are stumped as what this could be. Any help would be helpful. Thanks. Here is a pic of the setup as it is right now.
The pic is pretty much useless. Can't see the details on the tank plumbing.....
Insufficient return line size?
Insufficient/no tank vent?
Fuel psi is?
Voltage at the pump is?
Pump ground is?
Volt drop testing done?
Insufficient return line size?
Insufficient/no tank vent?
Fuel psi is?
Voltage at the pump is?
Pump ground is?
Volt drop testing done?
Staging Lane
Joined: Dec 2011
Posts: 90
Likes: 1
From: Melbourne, Fl
I am assuming you are describing a return system? If so, I fought this problem for almost 5 years (with no positive input from Aeromotive). The FUEL is being heated in the normal course of operation and eventually causes the pump to cavitate (which of course, will manifest itself as a "hot" pump).
You will solve your problem if you will go "in-tank" with your pump/s. Any number of manufactures (including Aeromotive) have excellent in-tank systems, and if you search around, you'll find big power systems now supported perfectly !
My problem occurred in a blown 4.6 32 V (560 RWHP), that is installed in my '93 T "Bird...since going in-tank, no problems, no matter how high the outside ambient...
You will solve your problem if you will go "in-tank" with your pump/s. Any number of manufactures (including Aeromotive) have excellent in-tank systems, and if you search around, you'll find big power systems now supported perfectly !
My problem occurred in a blown 4.6 32 V (560 RWHP), that is installed in my '93 T "Bird...since going in-tank, no problems, no matter how high the outside ambient...
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
The picture is hard to see.....but it looks like the pump is higher than the level of fuel in the tank, and on a hose about 6ft long.
Not a bit of wonder it's killing pumps !
EFI pumps must always have a good clean gravity feed. Never have them suck.
Put the pump in a sensible location, make sure there is a suitable filter and ensure an un-interrupted supply of fuel at all times and they will live a long and happy life.
And a large flat tank like that....is less than ideal unless it has very good internal baffling/sump to ensure that un-interrupted supply of fuel.
Not a bit of wonder it's killing pumps !
EFI pumps must always have a good clean gravity feed. Never have them suck.
Put the pump in a sensible location, make sure there is a suitable filter and ensure an un-interrupted supply of fuel at all times and they will live a long and happy life.
And a large flat tank like that....is less than ideal unless it has very good internal baffling/sump to ensure that un-interrupted supply of fuel.
