Anyone know which relay in the fuse box can be used to run the fuel pump with the car off on a 2001 and earlier? The later models had a C/OPN relay that can be used, but those relays do not appear on the first several years of the 100 series. Thoughts? Trying to drain the gas tank without opening the top cover and going with old school hose syphon.
Run Fuel Pump with car off?
- Thread starter apalt
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You can test-run the pump through Techstream. I think you risk fuel pump damage by running it long enough to drain the tank. I would siphon. OEM fuel pumps are not cheap.
There is no separate fuel pump relay. The fuel pump ecu in the left rear 1/4 is tied into the efi circuit.
You can jump the pump after disconnecting the harness from the ecu but I'd only jump with a fused 12 volt jumper
for any extended period of time.
As previously mentioned I'd go for the siphon for anything more than a couple gallons. The time it'll take to access the ecu vs lifting the seats and carpet isn't worth the hassle of jumping it.
You can jump the pump after disconnecting the harness from the ecu but I'd only jump with a fused 12 volt jumper
for any extended period of time.
As previously mentioned I'd go for the siphon for anything more than a couple gallons. The time it'll take to access the ecu vs lifting the seats and carpet isn't worth the hassle of jumping it.
Would OP need to come in from the top or could he drop the syphon / pump hose down the filler neck? Do we have some sort of anti-roll stopper deal in there?
Unless it's integrated into the metal section of the filler I believe it's a straight shot through. Parts diagram doesn't show anything pertaining to a rollover valve.
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Thanks for the consult on this. Looks like I'll siphon. In my searches on this, there are several accounts where they attempted to siphon from the filler, but can't get a hose down because of either an obstruction of just an inability to get it to the bottom of the tank.
When I emptied mine to be replaced, I pulled off the filler tube soft hose under the truck at the tank inlet and siphoned from there.
Isn't fuel pump designed to run for hours?
Try disable the starter by pulling a fuse or relay, to prevent the engine from cranking. Then turn and hold the key at "crank" position and see if fuel is coming out from the fuel line before the fuel filter. Sorry for the lack of details. I forgot how I did it before.
@medtro - Isn't fuel pump designed to run for hours?
In theory, you're right. Running under load (backpressure in the system) may mean that they don't work as hard (the differential pressure isn't as high when in a closed-loop fuel system).
Of course, when the tank runs dry, the pump will get no cooling effect from being immersed in fuel, but whether this hurts the pump is anyone's guess. I would suspect Aisin or Denso pumps are built to a higher quality spec than some.
I guess someone on Mud needs to run one and burn it out and then tell us
In theory, you're right. Running under load (backpressure in the system) may mean that they don't work as hard (the differential pressure isn't as high when in a closed-loop fuel system).
Of course, when the tank runs dry, the pump will get no cooling effect from being immersed in fuel, but whether this hurts the pump is anyone's guess. I would suspect Aisin or Denso pumps are built to a higher quality spec than some.
I guess someone on Mud needs to run one and burn it out and then tell us
