Sub Tank Fuel Pump blockage?

[FNQGU]

Ok, sorry - another of these sub tank fuel pump issues....

I recently had long range tanks fitted to my GU (both the main and the sub), and have now found my sub tank is not pumping across into my main tank. It was working fine.

When I say it isn't working, I have checked by looking down the main tank filler, while the sub tank button is activated, and no fuel can be seen coming from the inlet pipe. The green light on the dash switch came on as normal, until I started with the multimeter on the fuse panel, at which point the "Sub Tank" warning light on the dash came on, and it refused to work again. I then isolated the main battery and re-set the warning light, solving that problem.

To further trouble shoot the issue, I checked the fuses (all ok), and put the multimeter on the pump wires (also ok). Please correct me if I am wrong, but the sub tank fuel pump is the small in-line pump that sits externally to the tank, just in front behind an L-shaped protection plate? See pic below after protection plate removed?

I also noticed that the in-line filter from the main tank to the fuel pump quite clearly contained a lot of metallic filings and grit (also see pic...). I am guessing that the metallic filings have come from the manufacturing process and that the manufacturers did not bother to flush the tanks after completion.

Q1 - Where is the earth wire for the sub tank pump? Does it go back up to the sender unit in the top of the sub tank, and then back down to the one that can be seen in the bottom of the pic? (I cleaned this one up and it made no difference.)
Q2 - Can these in-line pumps be blocked by grit and metal filings? I assume they are a diaphragm type pump?
Q3 - Can they be pulled apart and cleaned out or are they throw away items if blocked up?

Cheers
BenK

[Col.T]

G'day Benny,
surprised you've not got the lowdown from the gurus yet and I can't help as I've never gone down the L/R tank route.
Coupla points though.
Where'd you get the tanks ?
That junk in the filter really doesn't look like a major manufacturer's crap.
Who did the job? Reckon it wasn't you 'cause you'd know the source of the filings if you'd checked out the interior of the tanks.
Maybe you've got a case to go back and not only question the filter/tanks but the wiring to go with them.
If that's not an option, the GU I've now got has two tanks and I'd hope that the wiring was the same on your new one, particularly as the pump doesn't look like a new one. Accordingly, the wiring diagram in the manual should give you a clue.
Good luck mate
Col

[FNQGU]

Thanks Col,

Yes, I have fired off a dirty email to the installer of the tanks. I understand they were manufactured by a small operator in Perth, but will find that out too. I'll pull the filter and the pump out tomorrow and have a good look at it all. Due to the amount of crap in the main inline filter, I am suspecting that the sub tank pump has failed for the same reason. If I can't clear the pump, I suppose I'll have to replace it. If that doesn't work then I suppose I'll start tracking down the wiring and earth points.

Cheers
Ben

[Avo]

hey mate if the tanks were new when you had it fitted I'd be taking the car back,the filter pic is something they cannot argue with.Good luck,keep us updated.i have lr tanks but never had a problem or had a look so I can't help.Had crap in my main tank not long ago and had to drop it and clean it out,that's why I asked if your tanks are new,looks like what I got off the bottom of my tank,old rust and gunk.

[FNQGU]

Tanks were brand new. Have only filled the sub twice before the pump packed it in. Brunswick Diesel installed the tanks but they were sourced from somewhere local to Brunswick. Not sure who. Brunswick also have a relationship with Gryphon Engineering here in Cairns, and I've already shown them the problem. They want to pull it all out and flush the lot and probably replace the sub tank pump but can't do it until late next week. I haven't had the conversation regarding fault or cost as yet...

As usual though, this occurs just before a planned trip to do the Maytown track, so I will be pulling the pump and filters myself and trying to get it to work before i go. I'll take a few pics if I find anything interesting and will certainly be chasing it further to flush the tanks properly as soon as I get back.

[FNQGU]

Ok, I pulled the sub tank transfer pump out today and yes, it is a sealed unit that is nigh impossible to open without causing serious damage, which I did... The pump is the diaphragm type. There are two bolts that appear to hold it together, but it is well sealed with glue and when you do manage to force open the two halves you will find that one half is filled with foam around the electrics and the second half holds the diaphragm. It doesn't seem to be of the type you can just give a clean out and put back together, which answers one of my original questions.

As the pump was obviously now phucked, I raced around the wreckers and pulled one off a GU ute and bolted it straight in. As I am heading off on a trip tomorrow I didn't have time to drop both fuel tanks and flush them properly, so I fitted an extra in-line filter before the pump, and bought a spare to take with me.

By the time I drove the 12klms home and checked the filter for grit and filings again, I found it already starting to get more crap in it. Not happy! I think I will change out my main fuel filter tomorrow before I go, just to be cautious.

The first pic shows the looped fuel line and extra in-line fuel filter that I just installed. The fuel comes in from the aux tank on the right hand end of the pump and exits out the left hand end back to the main tank.

The second pic shows the amount of crap already in it by the time I drove home, all of which would have ended up in the pump.

Also changed out the in-line filter from the main tank and put in a new one. That one at least only showed some minor particles when I got home as per the third pic.

On a side note, this little episode made me start to think about carrying a spare sub tank transfer pump for emergencies, as besides trying to drain everything with a siphon, and then transferring to the main, I can't think of a way to cover this eventuality if in remote areas. Then again, how many damn contingencies do we need to plan for...

[MudRunnerTD]

Hmmmmm.

Bugger! Mate I am not sure I have an inline filter like that in my line? Is that OEM? There certainly is a filter but its not an inline one like that.

Obviously the filter will only have flow as you do the transfer and you will transfer the hole 70lts in one go.

Does not look right, certainly the tank needs to be dropped out and flushed. Given it was New its a no brainer! Not your fault! The cost will be bourne by either the manufacturer of the tank(likely) or the guy that fitted it.

Have you cut open that inline filter and had a good look at the rubbish? Is it dirt or steal?

[FNQGU]

Might have been my poor explanation...let me add some extra detail.

My transfer system when I first got it was like this - Sub Tank transfers to main tank via the transfer pump (and had no inline filter). This all worked fine and dandy until the new long range tanks were fitted. The main tank has an inline filter before a small electric inline (booster?) pump that sits on the chasis just in front of where my sub tank pump is. This then heads up to the engine bay... I think this is pretty much standard Nissan getup? Not certain though, as my last Nissan (a G60) ute, was slightly more...'agricultural', I think the word is...

So, due to the dramas with the shit in my sub tank (all looks like metal filings), I stuck an inline filter just before the sub transfer pump, basically to save the transfer pump from getting clogged up with grit. I had about a 12" length of fuel hose, so just looped it and zip-tied it and put the filter in the middle, before re-connecting to the transfer pump. It might be a bit hard to see on that pic above, but none of that was there before today, it just fed straight to the transfer pump. Might be overkill, but I'm thinking that i will leave it there, even after I have dropped both tanks and flushed them properly. It certainly can't hurt.

The previous filter that contained all the metallic grit was the main in-line filter that sits between the main tank and the booster pump on the chassis. Yeah, I have kept that one and banged out most of the grit to have a good look at it. Some of it just looks like black grit, but most seems to shine like metal filings, which makes me think it is leftovers from manufacture.

For info I have included two pics of the fuel transfer pump when I opened it up. The pump was in two halves being held together by two philips head bolts but was quite difficult to pry open even after the bolts were removed. When I did break it apart (and yes, 'break' is the word), it looked like the below right hand pic with busted foam inside. The diaphragm is obviously in the left hand sealed part and did not seem to be able to be resuscitated... Maybe I should have kept digging, but it seemed like a moot point and I wasn't in the most analytical of moods about it at the time.

So far cost has been time and inconvenience, four new inline filters (2 x spares) for $25 and a second hand pump for $80 from the local extortionist who can kiss my ass if he thinks I will be returning for anything else. He saw me coming that is for sure...

[MudRunnerTD]

Hmmmm makes more sense for sure.

There can't be any doubt that they installed a dirty tank I reckon. Bloody bad luck there.

The LRA brand tanks are baffled with dividers and if you forgot to clean it out while building it'd be a bitch to clean out. I bought a second hand rear 147lt tank and expected to clean it out before fitting, basically could not. The baffles are full size and just have the corner cut off for 20mm to allow for an equalisation of fuel level.

Stick it up em mate.

[FNQGU]

Ok, so I am bumping this one back up to finish off what I should have done months ago…. drop the tanks and clean them out. I finally managed to tee up a mate who has a hoist and mechanical skills. Up until now, I have been relying on two in-line fuel filters to catch the metallic filings and crap that were in the fuel tanks. I have now done about 12000+klms and put a few tanks through the filters and changed them twice. The set that are on there now are reasonably clean of crap compared to the previous two filters. Unfortunately the Aux tank pump that I paid a fortune for from the wreckers is also playing up now and working sometimes and not others. I have to play with connections a bit more but I am starting to think about the whole setup and may replace the pump altogether.

Regarding the response from the installers - zippo. Not overly interested, and I will again send them the pictures I am posting this time around in some sort of attempt to make them feel guilty. At the end of the day I decided to do it myself so I knew exactly what was in my tanks, and how things were set up.

Whilst dropping the tanks, I also found a couple of issues that needed fixing that I wasn't expecting. It started like this…. Cape York Red!

http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_170644_178_zps649489d5.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_170644_178_zps649489d5.jpg.html)

Draining the main tank into a funnel into a a nice clean 44 gallon drum with the vehicle on a hoist. the funnel is one of those special fuel draining ones that has two large filters in it to separate out any particles. $19 at Auto1 and good value.

Dropping the main tank was a bit of a struggle, but not too bad. 4 large bolts at the rear of the wagon, up behind the tow bar, and three at the front. Disconnecting the filler hoses, return line and breather was not a difficult task with the vehicle up on a hoist. I would not try to do this if the vehicle was still on the ground or even on stands. There is simply not the room.

http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_174034_706_zpscaabf9a3.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_174034_706_zpscaabf9a3.jpg.html)
http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_174026_696_zps4acbedbc.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_174026_696_zps4acbedbc.jpg.html)

[FNQGU]

Blocked up the fuel lines with bolts and tape, and taped the main fillers and gave the tank a bit of a wash before opening the sender unit.

http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_175310_279_zpse5e47678.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_175310_279_zpse5e47678.jpg.html)

The Sender unit is the typical Nissan one installed into the aftermarket tank. It works somewhat like a toilet cistern float does. The pickup is the green bit at the bottom, the float is out to the right there. The return line is the other pipe to the left and mounted on it is the low fuel indicator that activates the fuel light on the dash, although I am not sure exactly how it works, but I can see the wire so can guess what it is.

http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_174841_287_zps6b2898d6.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_174841_287_zps6b2898d6.jpg.html)

A couple of shots of the inside of the tank…

There are two things of interest here. I first saw the bubbles on the bottom of the tank, which is water in the fuel. Happily there was very little.

The second thing I saw was the wear mark on the bottom of the tank from where the green pick up bit of plastic sits. That is a good thing, I think, as it means the pickup is right at the bottom, or as close to it as possible.

http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_175020_503_zps6ca19724.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_175020_503_zps6ca19724.jpg.html)

Also of note in there were the bits of welding splatter that are dotted around. Most of these were solid to the bottom, and in general, when looking around with a torch, there wasn't too much in the way of filings or other gunk. A nice clean tank…

The construction itself also looked good. The baffles were all the way to the top and it was a good strong design.

And then I found the magnet… Many tanks have a magnetised drain plug, like some sump plugs are. This one didn't, but they had put a magnet in the tank, about half way up the side. It looked like a hedge hog.

http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_174951_179_zps3bd510a0.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_174951_179_zps3bd510a0.jpg.html)
http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_175001_517_zps2c9cb667.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_175001_517_zps2c9cb667.jpg.html)

[FNQGU]

So we decided to go fishing… with a magnet on a stick!

http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_175213_486_zps1fbcc80f.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_175213_486_zps1fbcc80f.jpg.html)

and came up with bugger all.

http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_175353_372_zps09956497.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_175353_372_zps09956497.jpg.html)

Which is a good thing. Still, what we did fish out was all metal. Not a good wrap for a tank builder!!

However, in doing all this, I found out that I had a couple of inches of fuel in the bottom of the tank when the warning light comes on in my dash. Always good to know.

http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_175616_262_zpsb8894cdd.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_175616_262_zpsb8894cdd.jpg.html)

And, I now understand a bit better why my fuel gauge doesn't move for ages, and then drops rather rapidly. Apologies for the upside down sender unit here, but I only have one hand… It shows the difference from where the float is, when fully raised, to where the top of the tank mount is for the sender. And then, I need to allow for the couple of inches on top of that as the sender unit is recessed into the tank quite a bit, as you can see in the background on the tank.

http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_175725_561_zpsad1ac514.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_175725_561_zpsad1ac514.jpg.html)

ps. that drain goes into a trap, not onto the Great Barrier Reef…no animals were harmed in this exercise. Also, 99.99% of that is just water from me hosing off the tank.

[FNQGU]

So what I wasn't expecting was hose damage. This line is my breather line and by the looks of it, it had been rubbing like mad on the floor above it.

http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_180949_850_zps17355782.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_180949_850_zps17355782.jpg.html)

http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_181011_073_zpsb08abb24.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_181011_073_zpsb08abb24.jpg.html)

Not good. Might have been a nasty little water leak into the tank under the wrong circumstances.

[FNQGU]

So, next was dropping the sub tank to see how it was inside.

The sub tank is on the driver side midships and is secured by two bolts at the rear and two at the front. Had to remove the shroud for the sub tank pump to get at the front bolts, but no real dramas. The sender unit plug was probably the biggest pain in the ass to remove but then it dropped down with a bit of jiggling and lowering of the rear first.

http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_191303_070_zpsb7dd86e3.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_191303_070_zpsb7dd86e3.jpg.html)
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Don' worry about the multi-coloured look of the tank, we were just drying it off with the air compressor.

The sender unit came out easily and also showed a nice clean inside of the tank, although we found the magnet was mounted on the roof of the tank, right beside the hole for the sender. Why it was there I am unsure, but we re-located it down into the collection area, which is the square bit on the side towards the top left of the rectangular catchment. The crap in the bottom of the tank is all welding spatter, but most of it was solid.

http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_192101_743_zps12e7ff58.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_192101_743_zps12e7ff58.jpg.html)

[FNQGU]

The last thing of interest was the wear marks on the outside of the tank caused by the Nissan Rear Upper Control Arms (correct me if I have the name wrong). I have read that when a long range sub tank is installed that Superior Engineering recommended a bent up arm be installed… this is probably why.

http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_192214_063_zps825261f3.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_192214_063_zps825261f3.jpg.html)

http://i935.photobucket.com/albums/ad197/BenKDJ/IMG_20140117_192331_084_zps31f08931.jpg (http://s935.photobucket.com/user/BenKDJ/media/IMG_20140117_192331_084_zps31f08931.jpg.html)

That block that looks like a bump stop, has obviously been rubbing on the sub tank, and I have no doubt, if given enough time, there is a possibility it could have rubbed through. The only thing in my arsenal at the moment to address this is a stolen arm from a GQ, which doesn't have the 'bump stop', and so will probably be ok.

Anyway, I'll have to look at this tomorrow….

[FNQGU]

To finish up, I grabbed a couple of spray cans of Septone body deadener and gave the tanks a good clean up and spray before we re-installed them.

While we were at it, we made up a bit of a light duty transfer case protection plate from a bit of left over 6mm Alloy Plate. It wasn't a great fit, so we added two extension tabs to get it to bolt up properly. I was a bit slow on the photos with this one, but the alloy was put into a bender for a neater fit. Then basically we drilled a few holes and bolted it up. The holes at the front were already part of the cross member, and had a welded nut on the bottom side. When we bolted the plate up I added two nyloc nut to the backs of the bolts as well.

http://i935.photobucket.com/albums/ad197/BenKDJ/Mobile%20Uploads/IMG_20140118_092356_438_zps6ef9304c.jpg (http://s935.photobucket.com/user/BenKDJ/media/Mobile%20Uploads/IMG_20140118_092356_438_zps6ef9304c.jpg.html)

The rear holes in the round pipe bracing are just on the bottom. These were drilled right through and we used an 75mm M8 bolt to secure the back.

http://i935.photobucket.com/albums/ad197/BenKDJ/Mobile%20Uploads/IMG_20140118_092400_588_zpsdbb57f29.jpg (http://s935.photobucket.com/user/BenKDJ/media/Mobile%20Uploads/IMG_20140118_092400_588_zpsdbb57f29.jpg.html)

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