HOW TO: Drain Fuel Tank

[silvapain]

I had to drain a full tank of old fuel after my engine build, so I thought I might as well make a How-To for it...

1. Open engine bay fuse panel, and remove the primary fuel pump relay (labeled 'Circuit' in the diagram on the cover)

2. Create a jumper cable by crimping on two spade terminals on a short piece of wire. I used 14ga wire.

3. Plug one terminal into the port on the the fuse panel closest to the windshield. This is the +12VDC terminal:



4. Disconnect the blue fuel line connector on the HPFP. This is the line from the fuel tank to the HPFP (low pressure line).

5. Using a funnel and hose, run a line from the disconnected fuel line to a gas can:



6. Connect the other spade terminal to the port on the fuse panel just next to the one used in step 3 above. This will start the ITFP. NOTE: fuel pump relay 2 controls the high/low speed for the pump. with the relay not energized, the pump will run at low speed (which we want):



7. Profit:



Disconnect either jumper lead to stop the pump.

[TWOptSL0W]

youre welcome

[Mase33]

holy crap thanks for information !

[Rokusek]

Originally Posted by silvapain I had to drain a full tank of old fuel after my engine build, so I thought I might as well make a How-To for it... 1. Open engine bay fuse panel, and remove the primary fuel pump relay (labeled 'Circuit' in the diagram on the cover) 2. Create a jumper cable by crimping on two spade terminals on a short piece of wire. I used 14ga wire. 3. Plug one terminal into the port on the the fuse panel closest to the windshield. This is the +12VDC terminal: 4. Disconnect the blue fuel line connector on the HPFP. This is the line from the fuel tank to the HPFP (low pressure line). 5. Using a funnel and hose, run a line from the disconnected fuel line to a gas can: 6. Connect the other spade terminal to the port on the fuse panel just next to the one used in step 3 above. This will start the ITFP. NOTE: fuel pump relay 2 controls the high/low speed for the pump. with the relay not energized, the pump will run at low speed (which we want): 7. Profit: Disconnect either jumper lead to stop the pump.

Thank you good sir! I will be using this method this weekend to also drain an entire tank of gas from my car before start up as well!!!

[865ms3]

@silvapain; can you confirm this is the same on the gen2?

edit: this works as well on the gen two. the relay is in a different spot. i just tried it. standing at the driver side fender you will jump the two horizontal plugs in the circuit. these will be the two closest to you.

[Carl]

Sub

[Snotrocket]

@865ms3 pics?

[865ms3]

Originally Posted by Snotrocket @865ms3 pics?

i didnt take any. if you pull the "circuit" relay stand at the drive side fender. looking at the fuse box it will the the two horizontal plugs you jump (going off of my memory and my previous post)

[2.3speed06]

MS6?

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[superskaterxes]

theres a check connector on the MS6 in the underhood fuse box that you just ground one of the pins and it does the same thing.

[El_Diablo]

Just wanna say thanks again for this thread. Me and @sho used this method to drain about 9-10 gallons of bad fuel (Akron area stations have had issues lately) from his tank tonight before the Toledo autocross tomorrow. This method is the perfect one do use in situations such as this.

[mxlplx71]

this is great when you want to go to the track, but have a lot of fuel in the car, thanks for the advice on this last year.

[KRheeder]

Can this also be used to drain the tank of suspected water mixed with my fuel?

[sidekick]

Originally Posted by KRheeder Can this also be used to drain the tank of suspected water mixed with my fuel?

Well it drains the tank, so yes?

[KRheeder]

Originally Posted by sidekick Well it drains the tank, so yes?

Yeah it does but im just thinking that seeing that water is more dense and the fact that it doesn't mix with fuel it will lay at the bottom of the tank.

its a stupid question I know, I don't have any experience with it hence the question.

[cuethenoise]

Correct me if I'm wrong, but wouldn't this be hard on your low pressure fuel pump? I know most fuel pumps use the fuel for cooling and lubrication. Wouldn't running your tank dry like that put a lot of wear and tear on it? Not to mention it will suck all the gunk at the bottom of your tank into your fuel system and threw the pump. Seems like a good one time thing and not something to do all the time.

[sidekick]

Originally Posted by cuethenoise Correct me if I'm wrong, but wouldn't this be hard on your low pressure fuel pump? I know most fuel pumps use the fuel for cooling and lubrication. Wouldn't running your tank dry like that put a lot of wear and tear on it? Not to mention it will suck all the gunk at the bottom of your tank into your fuel system and threw the pump. Seems like a good one time thing and not something to do all the time.

You're running the pump at low speed, which means it will not need as much cooling/lubrication. You also shouldn't be doing this every week, so the wear/tear should be negligible. The pump always sucks from the bottom of the tank, so all of that "gunk" would be sucked up whether the tank is low or not. That's an old wives tale as far as I'm concerned. This is also why fuel pumps have filters.

Originally Posted by KRheeder Yeah it does but im just thinking that seeing that water is more dense and the fact that it doesn't mix with fuel it will lay at the bottom of the tank. its a stupid question I know, I don't have any experience with it hence the question.

But how do you know there is water in your tank? It shouldn't be an issue getting the water out this way, because the fuel pump will remove almost everything out of the tank doing it this way. There may still be a small amount of fuel left in the tank after doing this.

[cuethenoise]

Originally Posted by sidekick You're running the pump at low speed, which means it will not need as much cooling/lubrication. You also shouldn't be doing this every week, so the wear/tear should be negligible. The pump always sucks from the bottom of the tank, so all of that "gunk" would be sucked up whether the tank is low or not. That's an old wives tale as far as I'm concerned. This is also why fuel pumps have filters.

Yeah I sort of agree, that is why I said maybe a one time thing, but some of the peeps above said they would use this method before going to the track. I would use the tried and true siphon method for this to be honest.

[KRheeder]

Originally Posted by sidekick But how do you know there is water in your tank? It shouldn't be an issue getting the water out this way, because the fuel pump will remove almost everything out of the tank doing it this way. There may still be a small amount of fuel left in the tank after doing this.

Was driving home after work today, stopped to put in some fuel.
Left the gas station and 2-3 mins later the car started acting up. Would bog at times, had no power. I had to drive slowly. Initially I thought it might be a boost leak. When I got home I checked all the clamps etc. Installed everything again. car would start, idle roughly for like 5 seconds and die. The car was fine up to the point where I stopped at the gas station. Very bad batch of fuel or water in the fuel is my best guess. I cleaned all the sensors, checked all my connections etc

[Agent_Orange]

Originally Posted by cuethenoise Yeah I sort of agree, that is why I said maybe a one time thing, but some of the peeps above said they would use this method before going to the track. I would use the tried and true siphon method for this to be honest.

What makes you think it's bad for the pump?

It's doing what it does any other time it's operating, but instead of going into the HPFP, it's going into a gas can.

As long as the pump is promptly stopped when fuel is no longer flowing, there should be no issue.

I would be more concerned with fuel flowing near live/exposed electrical circuits.

[KRheeder]

This method works great. Turned out the petrol attendant and the shell garage put diesel instead of unleaded. What a mission to get it all out and the system clean. For the guys with mk2's, ive attached jumped circuit as its in a different location.

[sidekick]

You should do it again with gas run through it before starting the car.

[KRheeder]

I did yeah

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[kbz0129]

@BZiggy10 Quick way to empty the tank.

[mrQQ]

So I wonder what is the exact size of our fuel tank. I know it's listed to be 15,9 gallons, but is there a reserve?

[Big D]

My MS6 sat in storage for 2yrs. Tne fuel stabilizer bottle was still on the counter that sent to my younger brother to put in when I left to Japan. I am Emptying it completely and maybe running gas through. I'm sure its bad.

Or should I siphon it all out?

[batmsp3]

maybe I'm going full retard, but I was hoping to get clarification for the ms6. I would like to add pics after I am successful (or fuck something up) to help others.
@superskaterxes; where/what is the check connector you are referring to?

[batmsp3]

Think this might be it for the ms6

[MSP611]

easy and smart

[sailnaked6842]

I know I'm kicking the dust off this thread but just to confirm that for the MS6 you are only pulling the check connector and grounding the top right pin and will not need a jumper?

[batmsp3]

Originally Posted by sailnaked6842 I know I'm kicking the dust off this thread but just to confirm that for the MS6 you are only pulling the check connector and grounding the top right pin and will not need a jumper?

yup ,just take a wire from the check connector and connect it to ground.

[swosko]

Thanks a ton for detailing this. Worked like a charm on my 08 MS3.

[Mitchell5]

Thanks for all the info. I have a 2003
Protege5 and wonder if any of
You could confirm exactly which leads to jump? I am not sure if the relay is the same as on the 3. As responsibilities force me to drive a family truckster most days, it would be wonderful to get the 5
Back on the road. Thanks