how can i drain my fuel tank ?

Discussion on fuel delivery & intake/exhaust tech & mods.
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Sh00bs
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Joined: Tue Jun 22, 2021 7:32 am

how can i drain my fuel tank ?

Post by Sh00bs »

i took my car off the road about 5 months ago to do a LSA install... it was summer, i was driving my other cars and dragging my feet.
Well she's done, base tune loaded, it runs, rich, moves under it's own power (to putt around the house and drive onto the trailer to take to get tuned) but i'd like to take the 5 / 6 mo old gas out of the tank and put some fresh stuff in it for the tune. what's the easiest way to do this ?
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Mooseman
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Re: how can i drain my fuel tank ?

Post by Mooseman »

Could disconnect the fuel line at the rail, connect a hose to it using a stub that's the same as the fuel rail and turn on the fuel pump. I used to be able to do this on older trucks by jumping the fuel pump relay but not sure with these and their fuel pump control modules.
2011 Caprice PPV, former RCMP test vehicle, never put into service
Build Thread: http://www.newcaprice.com/forum/viewtopic.php?t=2419
Sh00bs
Posts: 43
Joined: Tue Jun 22, 2021 7:32 am

Re: how can i drain my fuel tank ?

Post by Sh00bs »

Mooseman wrote: Tue Dec 13, 2022 2:20 pm Could disconnect the fuel line at the rail, connect a hose to it using a stub that's the same as the fuel rail and turn on the fuel pump. I used to be able to do this on older trucks by jumping the fuel pump relay but not sure with these and their fuel pump control modules.
yeah that's kinda where im at... not sure if it would mess anything up by jumping the relay. i "think" with my HP tuner cable i could command it ON but ive never messed with that
Sanford
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Re: how can i drain my fuel tank ?

Post by Sanford »

I emptied a tank by just putting an old clapped out AC gauge set hose on the fuel rail pressure fitting and just started the engine and let it idle. The manual stated that the fuel line needs pressure on it to siphon fuel out of the left side of the tank. Since you have HP Tuners and can command the fuel pump on, you should not have any problem emptying the tank.
Sh00bs
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Re: how can i drain my fuel tank ?

Post by Sh00bs »

Sanford wrote: Fri Dec 16, 2022 10:02 pm I emptied a tank by just putting an old clapped out AC gauge set hose on the fuel rail pressure fitting and just started the engine and let it idle. The manual stated that the fuel line needs pressure on it to siphon fuel out of the left side of the tank. Since you have HP Tuners and can command the fuel pump on, you should not have any problem emptying the tank.
that's a great idea! unfortunately i dont have one of those... im going for tuning today, he's going to command my fp ON in hp tuners and i'll remove the shrader valve insert to drain the half of tank or so it has

i can confirm that sending 12v to the Grey wire that goes to your fp will NOT command it on. it hits the module first and that needs a signal to trigger it on
Sh00bs
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Re: how can i drain my fuel tank ?

Post by Sh00bs »

so my tuner (Dave Katz, EFI Specialties) was able to turn the FP on, but it would only stay on for like 3-4 seconds, then he'd have to tell it to turn on again. weird. we eventually got it all drained from the shrader valve on my fuel rail (LSA)
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