# Inline walbro fuel pump question(wiring)



## 2NICE4RICE (Jun 29, 2003)

I'm getting ready to install a new inline fuel pump on my mk2 vr6. On the fuel pump there appears to be only a + and a - , however on the old leaky fuel pump under the car it appears to be a four wire connector...??

I have been told this is fairly straight forward to do. Any help would be huge!
Thanks!


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## Scrubbs (Mar 14, 2006)

4 pin under the car? Pics? or is it a 4 wire 2 pin?


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## 2NICE4RICE (Jun 29, 2003)

That's a good question... I just looked under quick his morning I will check it out better tonight. 
Thanks!


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## 2NICE4RICE (Jun 29, 2003)

I checked it out, it's a two pin, there's two brown and one red and one red with yellow stripe. I'm assuming just join the reds and join the brown (ground) and that's it?


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## Scrubbs (Mar 14, 2006)

Yep, they spead the load over the wires, it was an easy design change. Saved them from redoing the harnesses for specific models. Make good crimps and connections, its the lifeblood for boosted cars.


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## 2NICE4RICE (Jun 29, 2003)

Ok thanks!! I'm just goin NA for now, this is the second mk2 I've had fuel pump failure but it seems stupid not to replace it with one of these walbros, especially considering I swapped in a vr. I spent a long time building it and finally got her running and what next? Fuel leaking... So im yet to take it for a rip, can't wait!
Thanks again!


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## Scrubbs (Mar 14, 2006)

The stock pumps last a long time, its the in tank lift pump that causes the problems. When it starves the main pump, the main takes alot of abuse.


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## 2NICE4RICE (Jun 29, 2003)

As far as I know my mk3 only has the pump underneath and not in tank pump


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## Scrubbs (Mar 14, 2006)

Mk2's had 2 pumps, lift pump in the tank, and high pressure in the "surge/accumulator box" underneath. Mk3's had one, in tank. Did you change the tank? Is this on a Mk2 or 3? or the Corrado?


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## 2NICE4RICE (Jun 29, 2003)

*Fuel pump*

Its a mk2 vr6, original fuel tank... Didn't think there was a pump in it. Either way the one underneath is leaking and I'm replacing it with the inline walbro one which should fix everything, correct?


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## Scrubbs (Mar 14, 2006)

Probably should spend a couple extra bux on the lift pump also. Or search and find the in tank install of that pump. SOmeone did it, might not be the exact pump, but same style i believe. What is actually leaking? the pump seal or the lines? the accumulator?


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## 2NICE4RICE (Jun 29, 2003)

Not really sure where it was leaking from... I have future plans of a turbo so I need this pump. I thought it was only the 16v that had two pumps... The intank pump is accessed thought the trunk correct? I'll have to take a look. 

I had planned to just rip off the big boxy old pump underneath, make a bracket that I can bolt the walbro to and a fuel filter on, hookup the lines and wire it and its done?


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## rstolz (Jun 16, 2009)

I've seen em mounted right in the engine bay too... that said, I mounted mine right where the old one was, like you're planning.


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## 2NICE4RICE (Jun 29, 2003)

Rsstolz, what did you do with the intank one?


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## rstolz (Jun 16, 2009)

mine didn't have one. 

If I remember correctly, and I may not, some cars do and some don't. Much like all VAG cars, they can't just keep it simple, they must confound us at every turn. I would have to look back at the bentley to be certain but it was either a difference with the GTIs or because the car was fuel injected instead of carbureted. 

Even if it does have one, as long as it still works you can mount the new pump ahead of the surge tank, which mine did have, and you should be fine. 

in tank pump feeds the surge tank, in-line pump pulls from the surge tank and feeds the engine. this will allow the in tank pump to prime the system, and keep it from becoming a bottleneck in the system. Without the surge tank, the walbro pump will suck fuel faster than the in-tank pump can supply it. In this case it will supply fuel at the correct pressure, but maybe not at the correct volume.


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## Scrubbs (Mar 14, 2006)

http://forums.vwvortex.com/showthre...alth-pump&highlight=aeromotive+fuel+pump+tank 
Check that out and see if it is what your interested in. i believie its been done with a walbro inline too. It wouldnt need the surge tank as much, but it will be noisey when fuel is low. That would be my concern, low fuel cavitation on acceleration or decel.


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## 2NICE4RICE (Jun 29, 2003)

That would be easier than what I was thinking I guess. I'm gonna clean out my trunk and see if I have an intank pump and go from there. Where is the surge tank located? 
Thanks for the help by the way


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## rstolz (Jun 16, 2009)

between the in-tank pump and the external pump. should just look like a canister with a line in from the tank, and a line out to the external pump.


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## Scrubbs (Mar 14, 2006)

black box under the rear passenger seat, under the car. the main fuel pump is screwed into the back side of it. Accumulator and filter is mounted to the sides of the pump, on the outside of the box. I have one sitting outside, ill shoot pics tomorrow.


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## 2NICE4RICE (Jun 29, 2003)

So i looked, took out the intank pump. The walbro appears too big to make work like that guy did . So I either need to buy the pump he used or do what originally planned and put it underneath. I couldn't see any surge tank unless its part of that whole accumulator box thing...


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## JoL (Dec 8, 2005)

I would suggest checking the load on your factory fuel pump wiring, whenever I installed a 195 or 255 I always relayed it with thick gauge wires or even put a dash switch. Make sure there is a new filter before the pump, I always installed mine closest to the tank, and you can use the tank pump as a feeder, but make sure your tank pump is unrestricted because walbros suck like a working girl right before Xmas.


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## rstolz (Jun 16, 2009)

surge tank = fuel accumulator. different terms, same thing.


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## 2NICE4RICE (Jun 29, 2003)

Oh ok I see. So I have an intank one that appears fine...I will leave it. I have the accumulator box with old fuel pump and everything underneath still. I'm still trying to figure out my best route here. 

I'll have to take a better look but is it possible to remove the old pump from that whole setup an replace it with the walbro one and still keep the factory surge tank and bracket and everything? Obviously it will need a bit of modding to mount.

Is it possible to just buy a mk3 style walbro and Ditch the surge tank and everything underneath? Or does that mean I have to swap gas tanks too...

This is tougher than I originally thought but I'm trying to figure out the easiest, most practical and clean looking option.


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## Scrubbs (Mar 14, 2006)

Since you have the pump already, ditch the box, run appropriate fuel injection fuel line for the return and feed, to the pump , use a mk3 fuel filter bracket and filter, and run that to the existing line. And replace the intank pump, there cheap. They cause the mains to fail usually.


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## 2NICE4RICE (Jun 29, 2003)

If I do that I'm back to not having a surge tank? The return line runs from the fuel rail basically all the way to the intank pump I believe? And the feed line from the intank (ill buy a new oem one) - to filter - to inline pump - to fuel rail? 

I dug out the old Bentley for the mk2 but there's not much that you guys haven't already helped me with In there. I snapped a couple pics of the accumulator box I will throw up this morning.


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## rstolz (Jun 16, 2009)

if you have an in tank pump, I wouldn't strap an external walbro on there without a surge tank in between. you'll end up choking the walbro, stressing it, and not getting the same volume of fuel to the engine, you'll get the proper pressure, but at reduced voume, in the end the walbro will fail.

a good small write up for why:

http://www.034motorsport.com/fuel-i...nclosed-fp34-044-fuel-surge-tank-p-21527.html

I am NOT advertising for them... Most of their stuff is over-priced, but they do have some nice technical tidbits.

You can also run the math by doing a flow test out of the in-tank pump, and another flow test using the walbro, transferring fuel from one container to another... compare the volumes and you'll see that the in-tank pump alone will not supply enough fuel to the walbro when in series without a surge tank.


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## 2NICE4RICE (Jun 29, 2003)

Ok I'm starting to make sense of it. That Bosch pump with the surge tank would be ideal except its $500!! I wonder if the walbro would fit in there or if the bosch and walbro are completely different sizes. Maybe I have to splurge...but I'm still sourcing options, I think it's my accumulator box that's leaking but I have a spare one


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## 2NICE4RICE (Jun 29, 2003)

Thank for help guys! Came across this:
http://forums.vwvortex.com/showthread.php?5737289-F-S-Fueling-Parts

This is likely exactly what I need, I ripped off the old stuff last night. I'm just researching how those fittings (AN) will adapt to my existing lines and how it all ties together. Don't want any extra holes or whatever


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## rstolz (Jun 16, 2009)

That 034 unit is crazy pricey. It's also over-engineered because it's a pump surround. it is pretty though.

Much cheaper to either use the stock "accumulator" or another aftermarket surge tank that gets mounted seperately. There is NO FUNCTIONAL BENEFIT to the surround style. You pay A LOT more for the convenience and show car sparkle of an all-in-one solution... that's it.

I went through this when determining my setup too. 

the stock accumulator (surge tank) isn't protected very well, so it's not terribly surprising that that would be leaking, especially if it's seen salty winter roads or spent a lot of its life outside. 

try replacing your accumulator and throwing a walbro in place of the stock external pump before deciding to spend the extra cash on an aftermarket surge, or all-in-one surround. 

also do some shopping around, fuel pumps vary a lot in price from store to store.


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## 2NICE4RICE (Jun 29, 2003)

Will my walbro replace stock pump in the original accumulator box tho? 300 isn't a bad deal with the bosch pump included tho. I'm more worried about how all my lines will connect to those NA fittings. Where can I source these separate style surge tanks??

This is all new to me sorry guys, learning lots tho

I have a spare whole mk2 setup, accumulator, pump and everything but want to upgrade now for future plans. So I also have a brand new inline walbro. I'm not afraid to go a different route if there is one and not have to use my new pump.


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## rstolz (Jun 16, 2009)

the accumulator is just an empty canister with an inlet and an outlet, there is no pump inside. here's another link i used to help teach myself (just found it again):

http://www.google.com/imgres?imgurl...a=X&ei=xnRsUKbkIaPRyQHy-ICoDw&ved=0CB0Q9QEwAA 

One benefit from the surge tank in the diagram is that they also have the fuel return line feeding into it, which would help reduce stress on the intank pump even more.

Surge tanks can come from ebay, Summit, 034, or any number of performance shops out there.


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## 2NICE4RICE (Jun 29, 2003)

Is that not the pump inside the accumulator/surge tank?


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## rstolz (Jun 16, 2009)

well I'll be damned. looks to be, yep. learn something new every day. I've never seen the mk2 setup in real 3. The mk1 is 2 seperate components. However the accumulator really is just an empty canister, yours just happens to have the external fuel pump sticking out of it (symantics, I know). 

All the same still applies though, except that if you go with seperating the surge tank and fuel pump, you will need to buy an aftermarket surge... or make one. Nice basic unit:

http://www.cxracing.com/mm5/merchant.mvc?Screen=PROD&Store_Code=CXR&Product_Code=FST02

I guess if you can get the walbro to fit where the stock pump is you'd be good to go.


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## Scrubbs (Mar 14, 2006)

Half my post didnt show up above.I also stated to try to find or fab a surge tank.2 ins 2 outs, with baffles depending on size. Rstolz has the right idea. The 034 unit is a great item, but it is pricy. You could sell the pump, or return it? and put it towards the 034 or other brand. You fuel unit doesnt appear to have the accumulator on it. Newer model. but that is the pump in the center. Did you find the leak? Source a new box. should be easy to find.


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## 2NICE4RICE (Jun 29, 2003)

Not exactly sure where is leaking, I don't want to replace it with a stock pump just because I know I want to upgrade for a turbo anyway. I put my walbro up In The classifieds already, someone will get a decent deal an I'm pending a sale on a barely use IE system with bosch pump.
Thanks, I will keep you updated!


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## 2NICE4RICE (Jun 29, 2003)

*Fuel issues*

Update!! 
Thought I would update this to help other people out possibly. I ended up purchasing the integrated engineering surge tank with bosch fuel pump submerged inside of it. It is pricey but I got it used but in new condition. I had to order special -6AN to 5/16" barb fittings from INtegrated engineering to work with my existing fuel lines. I made a bracket and painted it up all nice to mount it underneath where the old one was, looks great I think. Hooked up all the lines and gave it a shot, runs great and mainly no leaks now! Thanks to everyone for their input and help. 
I left the intank pump for now but I think in going to replace it with either a new one or a more efficient one. I may put a brand new FPR in as well just to be safe. 
The bosch pump is fairly loud but I have only run it in my garage which prob makes it sound a bit worse and I think with a new intank pump may help the noise a bit. At least now I should have no fuel issues when it comes time to boost my vr!


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## 2NICE4RICE (Jun 29, 2003)




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## justinhannoldVW (Jul 27, 2009)

seems legit! looks bigger than original, is it?? How it holding up? I think im gonna do this to my 16valve:thumbup:


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## 2NICE4RICE (Jun 29, 2003)

*Surge tank*

Haven't really got a chance to drive it due the weather here in Ontario . I've had it running and stuff and everything seems perfect. The pump is a bit noisy but I knew that prior to installing this. I will have no fuel shortage at least when I boost it soon!


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