Guide: How to remove fuel tank and swap pump

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Guide: How to remove fuel tank and swap pump

Postby tw2 » Sun Jun 27, 2010 1:32 am

I have no idea if there is already a write up but I am half way through this job so I figured I could post some info anyway. All the usual- jacks, good jack stands, safetly glasses from 20 years of shit falling off the bottom of your car when you are under there etc etc

I will start with this- the tank, this makes it easier to see what you are doing when you know what it looks like. Yes the tank can be removed with the filler neck attached, not only that, but it is pretty easy so there is no reason to try and disconnect it. Also the BGB says to remove the fuel level sender unit, once again there is no reason to do this. As you can see my tank isn't in too bad condition, there is some rust around the edges and the filler neck is probably beyond a save, at least at the bottom. I am still deciding whether I can be bothered removing the surface rust and painting it with por-15.
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Remove the large plastic shroud covering the tank, you will break every single 10mm bolt here, don't even bother trying not to, just repair them afterwards. In the boot (trunk) you will see on the left side where the 2 small looms come from the tank through the floor, remove the cover, undo the looms and pull them out of the cover, you do not need to undo the sensor from the tank, you would be risking a whole pile of dust and crap going into the tank when removing if you did take off the unit. The looms are the sender unit and fuel pump wires respectively and are the only things to worry about from in here.

Next remove the left side mud flap, the wheel if you like (I found that I couldn't as the locator ring on my wheel has fused to the hub- fun job for later but this proves you don't even need to remove the wheel), then remove the plastic shroud behind the wheel which gives you good access to the filler neck which you don't need- but it does give you good access to the fuel lines. In the middle of the picture are the rubber pads pasted all over the tank which all came off during cleaning- does anyone have a good method of reattaching these?
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These are the metal straps that hold the tank up, they are not the same. Do not try and undo the 17mm nuts on the front end of the straps, you will just destroy the brackets and get nowhere. Undo the 4x 14mm nuts on the rear of the fuel tank just inside the bumper, they are easy to access and usually not too destroyed by rust. Make sure your tank is empty- this job was very easy after this, turn the ignition switch to "on" and "off" repeatedly, this will turn the pump on for a few seconds as a fuel pressure priming pump for the engine before starting, you can collect the fuel either near the fuel rail return line or under the car by the tank either at the rubber return line or direct from the pump once you have separated the fuel feed line. It pulses about 40mL each time and you can drain 1/3 of a tank in about 10 minutes while stopping every minute to empty the 5L container into the mr2 parked next to it. You should/might be able to bridge Fp and B+ in the diagnostics port but it did not work for me, this is either because it only works with the engine on (unlikely), I did not bridge it properly, or more likely it does not work after my loom butchery and megasquirt install.
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This should be the only part which makes you want to give up on life- separating the 3 fuel lines. Two are rubber and come off with minimal encouragement with a flat head screwdriver. The other is the fuel feed line which has a flare fitting with 14mm on one side and 19mm on the other. A normal crappy spanner works for the 19mm but I recommend a proper high quality brake line spanner ie 6 sided spanner with a hole cut out the end for the 14mm side to avoid rounding it. I found I could rest the 19mm against the frame and just use both hands on the 14mm to undo it with a small extension, this was after 2 weeks of soaking it with PB blaster. Reaching through the wheel arch would likely work well but I could not do this. Probably an easy time to do your diff oil also. When you remove the tank you can use two methods depending on how much fuel is in there. If there is a fair amount get a plank of wood 700x300mm 1" thick, get two jacks on one side and a floor jack on the other and slowly lower it bit by bit, one jack in the middle is not stable and not a good idea. I started doing this but my tank weighed about 4-5kg so after a while I worked out that I could actually rest it on my upright foot and slowly lower it by hand, it took a small amount of wiggling to the the filler neck out.
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Good time to clean things like the filler hole on both sides, the surfaces were the straps came off so you don't both dirt and shit into the body after you reassemble. If you are really keen you could steam clean the under side of the car.
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Clean everything and soak the pump bolts in PB blaster or similar very well before attemping removal, you only get one shot at each, I would not want to have to drill a bolt out of a fuel tank. They are 8mm and should come out with minimal force. This is basically where I am up to so far. I have yet to decide how I want to do the wiring for my walbro. It comes with crush crimps but I am not sure how much I trust these. Some mr2 people have used crushed and soldered ring terminals and rivets to the pump body which looks a little more reliable, I may do this. Make sure your pump comes with proper rated fuel hose. Some of the cheaper kits come with crap which will dissolve in fuel fairly quickly. I got mine from ats but any of the good mr2oc board vendors will have quality kits.
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Finally this is from simba, everything he said was 100% correct for me, words of wisdom.
Simba wrote:1) Drain it. The simplest method is to use the fuel pump and attach a length of hose to the flare nut fitting after having removed it from the fuel hard line. Do not run the pump continuously once the tank is nearly empty-- short 15 second pulses with 15 seconds of rest between them. You do not need to completely empty the tank, a gallon or two remaining will not make much difference.

2) Feel free to snap off all the bolts holding the plastic cover-- I've never seen one that came out cleanly. You can drill out the studs and use threaded inserts to repair them.

3) Don't bother with the two large 17mm nuts on the bracket at the front of the tank. All you are likely to accomplish unless you have regularly greased the threads is to pretzel the brackets. Remove the REAR tank brackets. Each has two 14mm bolts if I remember correctly. Once removed, bend the straps out of the way. Once the tank is down you can remove the front brackets from the chassis and easily disassemble the straps and brackets for cleaning/painting.

4) Chances are good the inside of the tank will be clean as a whistle, though it's easy enough to inspect once you remove the fuel pump housing. Soak the bolts for several days in penetrating oil before attempting to remove them. Snapping one off will ruin your day. It's also a good idea to use a dremmel with a small wire wheel to remove any built up rust around the bolt heads-- the threads will be clean, but the heads tend to weld themselves to the top of the housing. When you re-assemble, USE STAINLESS HARDWARE.

5) It's a good idea to remove and inspect your level sender. The plastic housing with the potentiometer likes to separate from time to time. If it's in good shape, replace it with stainless BOLTS instead of the stupid screws Toyota thought were a good idea. Same goes for the vent housing.

6) If your tank is anything other than pristine (e.g. lots of surface rust), it's a very good idea to use a rust stripping product on it, spray it with etching primer, and then give it several coats of POR-15. Eventually the fuel tanks will no longer be made, and anything you can do to keep yours happy will keep you from having to buy a fuel cell down the road.

You generally will not need a jack to lower the tank if you get most all of the fuel out. I've done it by hand with ~12 gallons in it, which sucks, and with ~2 gallons in it, which is easy.

Don't forget to remove the rubber surround from the filler neck, and the wheel arch lining around the filler neck.

It's a good idea to take the opportunity to do the following once the tank is out:

- Coat the underside of the spare tire well and associated areas with a good rust paint like POR-15.

- Inspect your rear diff bushing. If it's worn, it's much easier to replace with the tank out.

- Thoroughly inspect all fuel hard lines for rust, cracks, pin holes, etc.

- It's a good idea to mark the tank somewhere before you reinstall indicating when it was last removed/inspected.
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Last edited by tw2 on Mon Jul 05, 2010 5:56 am, edited 2 times in total.
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Re: How to remove fuel tank and swap pump

Postby tw2 » Sun Jun 27, 2010 1:32 am

This is what the stock tank baffle looks like. This is what is saving you from running dry when cornering hard.
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New vs old. The walbro has a foam sleeve on so you can see it is physically a lot smaller than the stock pump. You can see I used the stock hose clamps rather than screw types which come in the kits. I trust the stock ones a lot more.
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This was taken from mr2oc. It is gss341 in an mr2 bracket (which look identical). The difference between gss341 and gss342 is the side the wire harness and feed ports are on the pump top. Essentially either one will be fine. It looks as though 341 might line up better, I bent the metal feed line out about 5mm.
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I decided to keep the noise condenser. It usually faces down and bolts onto the top of the stock pump. Here you can see that I rotated it around to face up.
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When wiring, all the kits come with crimps. I did not use these. Instead I drilled out the stock rivets and re-riveted it in place. Whatever you choose to do, just make sure you do your connections as close to the positive post at the top of the bracket. Why? because if your crimp/solder/rivet ever fails it means that there is no positive wire dangling around the tank looking for something to ground on. If your crimp was next to the pump and failed you have 10" of live wire looking ready to start a fire rather than 10" of dead wire attached to the pump which will simply just stop the pump and hence car from running. For my ring terminals, I crimped and then soldered them.
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Here is after the tank is installed back in. I coated everything in POR-15, I used a rust converter but I did not bother removing all the rust, probably got rid of 80% of it, there was not a lot anyway but I should easily get another 10 years out of the tank.
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I cleaned, removed rust and painted the metal straps. Removed the rubber liners from them and cleaned these too. All new hardware also. When replacing the tank there are no special tricks really. Bolt the front side of the straps back up, do not tighten the bolts all the way as they will need some movement to align the straps in the grooves of the tank. Another thing that will help a lot is if you have some M10 threaded rod. This will help with putting the straps back up on the rear side of the tank. It is very hard to get them close enough to put the original bolts back in but if you can use a 10cm piece of threaded rod you can bolt them into place on one side (since there are two holes in each mounting bracket) and then put the original bolts in one at a time. Check very carefully your electrical connectors are through the boot (truck) floor before bolting the tank back into place (I didn't :doh: ) Here you can see my awsome second coat, I ran out of paint brushes so used a cloth. When I confirm the pump works I will add the plastic shroud.
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Last edited by tw2 on Tue Aug 03, 2010 3:34 am, edited 3 times in total.
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Re: How to remove fuel tank and swap pump

Postby tw2 » Sun Jun 27, 2010 3:13 am

Does anyone know what the small black thing riveted to the pump bracket is? (pictured above) I think it is a noise condenser but not sure, I presume I can remove it?
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Re: How to remove fuel tank and swap pump

Postby Simba » Sun Jun 27, 2010 1:37 pm

tw2 wrote:Does anyone know what the small black thing riveted to the pump bracket is? (pictured above) I think it is a noise condenser but not sure, I presume I can remove it?


It's a small capacitor/condenser which protects the fuel pump from voltage weirdness. You want to keep it if you're using the stock pump wiring. If you go to a direct heavy gauge battery power feed via a relay, you can lose it.

Lots of fast, loud things.
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Re: How to remove fuel tank and swap pump

Postby tw2 » Sat Jul 03, 2010 11:52 pm

Simba, how did you deal with the broken bolts in the metal straps which hold the tanks up? Did you drill and tap them bigger or is there a good way to salvage the original's. They are pretty rusted on the inside.
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Re: How to remove fuel tank and swap pump

Postby Simba » Sat Jul 10, 2010 1:42 am

tw2 wrote:Simba, how did you deal with the broken bolts in the metal straps which hold the tanks up? Did you drill and tap them bigger or is there a good way to salvage the original's. They are pretty rusted on the inside.


You mean the bolts that hold the plastic tank cover on? I just drilled them out and used crimp-in threaded inserts.

Lots of fast, loud things.
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Re: Guide: How to remove fuel tank and swap pump

Postby aus jd 2703 » Sat Jul 10, 2010 5:40 am

quick question does the wire from the condenser go to the positive or negative?
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Re: Guide: How to remove fuel tank and swap pump

Postby tw2 » Sat Jul 10, 2010 7:45 am

Assuming blue has to be positive and black is negative (which is also grounded on the bracket) then the condenser is positive.

Yes that is what I meant thanks simba. I took it to my usual engineering shop to be drilled and re-tapped. I usually make a mess of these things.
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Re: Guide: How to remove fuel tank and swap pump

Postby tw2 » Tue Aug 03, 2010 3:44 am

Write up finished, hopefully this will help someone else.
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Re: How to remove fuel tank and swap pump

Postby MWP » Tue Aug 03, 2010 4:48 am

It will, thankyou.
Ill be dropping out my tank in the next week or so to fix a rather bad fuel leak from around the filler area :(

Simba wrote:It's a small capacitor/condenser which protects the fuel pump from voltage weirdness. You want to keep it if you're using the stock pump wiring. If you go to a direct heavy gauge battery power feed via a relay, you can lose it.


No, actually its there to stop noisy pump brushes from creating electrical interference that will effect the car radio, and if bad enough, other electronic systems (like the ECU).
It does effectively the same thing as condensers on points distributor systems did years ago.

I would leave it there.
And, the wire from it runs to +ve.
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Re: Guide: How to remove fuel tank and swap pump

Postby aus jd 2703 » Wed Dec 21, 2011 12:09 am

I'm having issues with my fuel gauge originally it was intermittent now it doesn't work at all so im planning to pull it out over the holidays and test it. But I want to know if I have to take the tank out? Or is it possible to pull the sender unit with the tank in the car?
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Re: Guide: How to remove fuel tank and swap pump

Postby aus jd 2703 » Thu Dec 22, 2011 11:05 pm

Any body know if I can remove it with tank in car?
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Re: Guide: How to remove fuel tank and swap pump

Postby tw2 » Fri Dec 23, 2011 4:42 am

Yes, remove the cover on the left side of the boot (trunk), I know you can access the wiring for it and I think you can remove it this way, not 100% certain.
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