# Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump?



## BMAN (Jun 9, 1999)

I'm trying to figure out if the fuel should push thru the filter or be pulled thru it? Thanks


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## n8burnz (Jan 15, 2009)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (BMAN)*

if the guy at C2 said it should be pushed through then set it up to push through and see how it runs.


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## VOLKS-MAN (Oct 7, 2000)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (n8burnz)*

I run mine after the fuel filter. No Problems.
The USRT kit is really good. You will need a section of 5/16" fuel injection hose about 2' long and the clamps. About a 2.5 hour install, pump and harness. Longer power wire to the battery will be needed depending how it's routed.


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## GTijoejoe (Oct 6, 2001)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (VOLKS-MAN)*


_Quote, originally posted by *VOLKS-MAN* »_I run mine after the fuel filter. No Problems..

x2


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## KubotaPowered (Jan 27, 2005)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (n8burnz)*

pumps can push fuel easier than they pull


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## VOLKS-MAN (Oct 7, 2000)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (KubotaPowered)*


_Quote, originally posted by *KubotaPowered* »_pumps can push fuel easier than they pull

This is true but if your stock fuel pump is in good working condition and the fuel filter is new you shouldn't have any problems. There are hundreds of people on this forum with secondary fuel pumps without issues. In fact most of the 1.8T owners with inline fuel pumps, the pump is located next to the valve cover.
If there was a direct replacement for the factory intank pump, USRT and other vendors would be selling them as the recommended solution.


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## VOLKS-MAN (Oct 7, 2000)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (VOLKS-MAN)*

Before I get flamed I do know we were talking about pre filter and post filter pump placement.


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## BMAN (Jun 9, 1999)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (VOLKS-MAN)*

Well here is how I have it now but when I get a chance I'm going to set it up to push the fuel thur the filter to see if it helps my bucking problem.


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## raddo (Dec 22, 1999)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (BMAN)*

Fuel filters are over rated


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## VOLKS-MAN (Oct 7, 2000)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (raddo)*

At what rpm are you having bucking problems?


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## BMAN (Jun 9, 1999)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (VOLKS-MAN)*


_Quote, originally posted by *VOLKS-MAN* »_At what rpm are you having bucking problems?

Not sure what rpm but when it gets close to 9-10 Ib of boost, but if I bypass the pump no bucking at all


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## VOLKS-MAN (Oct 7, 2000)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (BMAN)*

How are you bypassing the pump?


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## BMAN (Jun 9, 1999)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (VOLKS-MAN)*

I just pull the fuel line off the (out) of the fuel filter and put the stock line back and pull the fuse on the in-line pump.


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## VOLKS-MAN (Oct 7, 2000)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (BMAN)*

What type of bucking are you experiencing..ie between shifts or during power?


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## BMAN (Jun 9, 1999)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (VOLKS-MAN)*


_Quote, originally posted by *VOLKS-MAN* »_What type of bucking are you experiencing..ie between shifts or during power?

Major bucking under power, like someone shut the fuel off


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## jhayesvw (Oct 3, 2001)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (BMAN)*

if you have your power and ground swapped on your relay (like you posted you might) would that run your pump backward?
its worth a shot to try it again. replace the relay and make sure its wired properly.
or, you have a FPR issue. like its not keeping the fuel adjusted like it should be.


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## BMAN (Jun 9, 1999)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (jhayesvw)*

But without the pump installed I can boost to 16 Ib with no problem but it runs lean 13.5-14. With it installed it runs fine as long as I don't go into 9 and above of boost.
The only thing I can do at the point is to hook the fuel lines up to push thru the filter and go from there.
I've also tried a 4 bar fpr with no luck.


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## jhayesvw (Oct 3, 2001)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (BMAN)*

obd2 C2 doesnt like 4 bar, but i can see why you would try it. could richen up your mixture.
as for pushing or pulling through the filter. 
like stated earlier, there are dozens of people that run it the way you have it.
i think its wired wrong somehow. 
what if you pulled the hose off the outlet of the walbro and then disconnected the stock pump.
then turn the key to on (dont start it) .
see if fuel sprays out?
im grasping straws here, but thats free and very fast to try.


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## BMAN (Jun 9, 1999)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (jhayesvw)*

Finally fixed







I re-routed the fuel lines to push the fuel thru the filter and it fixed the problem. Man it sure pulls real hard. I hate to sound like a jerk but I put the blame on C2 because the directions they sent me stated to hook the pump after the filter.
The reason I'm upset about it is, it took me about two months off and on to fix it. When I sent the picture of the setup to C2 they said I had it hooked up wrong and they were voiding my warranty on the pump








I had them re-read the instructions they sent me and he realized I was right and he told me the directions were wrong but no apology was giving to me about the warranty on the pump.
Right now I'm running a 4 Bar FPR and I'm seeing no more then 11.5 at full throttle.
Thanks for all the suggestions http://****************.com/smile/emthup.gif


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## guy022077 (Feb 25, 2004)

no concerns about the wires being out in the open like that? do guys just make that box for sound or for wire cover?


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## BMAN (Jun 9, 1999)

*Re: (guy022077)*


_Quote, originally posted by *guy022077* »_no concerns about the wires being out in the open like that? do guys just make that box for sound or for wire cover?

No issues for me because mine doesn't see rain


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## 2.0t mk2 (Dec 23, 2007)

*Re: (BMAN)*

are you guys using the stock in tank pump with them?


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## Salsa GTI (Aug 29, 2000)

*Re: (2.0t mk2)*


_Quote, originally posted by *2.0t mk2* »_are you guys using the stock in tank pump with them?

Yes they are....
And you need not worry about running out of fuel with your ABA..because i dont


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## EuroSport98 (Sep 25, 2001)

*Re: (Salsa GTI)*

As a side question, are you guys protecting the terminals somehow? No adverse effects with rain?


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## PapioGXL (Jun 3, 2008)

*FV-QR*


_Quote, originally posted by *EuroSport98* »_As a side question, are you guys protecting the terminals somehow? No adverse effects with rain?


You should put some dielectric grease on any exposed connection.


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## BMAN (Jun 9, 1999)

*Re: (EuroSport98)*


_Quote, originally posted by *EuroSport98* »_As a side question, are you guys protecting the terminals somehow? No adverse effects with rain?

No but my car doesn't know what rain is


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## vdubracer83 (Apr 22, 2002)

*Re: (BMAN)*

im running a push setup and not having any fueling issues


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## joshisapunk (Oct 1, 2004)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (BMAN)*


_Quote, originally posted by *BMAN* »_Finally fixed







I re-routed the fuel lines to push the fuel thru the filter and it fixed the problem. Man it sure pulls real hard. I hate to sound like a jerk but I put the blame on C2 because the directions they sent me stated to hook the pump after the filter.
The reason I'm upset about it is, it took me about two months off and on to fix it. When I sent the picture of the setup to C2 they said I had it hooked up wrong and they were voiding my warranty on the pump








I had them re-read the instructions they sent me and he realized I was right and he told me the directions were wrong but no apology was giving to me about the warranty on the pump.
Right now I'm running a 4 Bar FPR and I'm seeing no more then 11.5 at full throttle.
Thanks for all the suggestions http://****************.com/smile/emthup.gif 

I had this exact same problem...same bucking issues around 9-10 psi. I hooked up my walbro the same way, following the directions that came with it (except mine came from CTS Turbo) and setting it up to pull through the filter. I spent weeks trying to track down the problem, and never even considered the fuel pump until i read this. I immediately went out and swapped the lines and the car is pulling like a demon now at 18 psi with no sign of bucking anywhere. 














for you


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## pubahs (Apr 2, 2002)

Any long term concerns with running unfiltered fuel through the pump initially? Not sure if the unfiltered fuel will have any effects on the internal workings of the pump
Just putting that out there - any one comment?


_Modified by pubahs at 2:18 PM 9-21-2009_


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## joshisapunk (Oct 1, 2004)

*Re: (pubahs)*

i imagine the in-tank pump must have some kind of pre-filter or screen


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## BMAN (Jun 9, 1999)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (joshisapunk)*


_Quote, originally posted by *joshisapunk* »_
I had this exact same problem...same bucking issues around 9-10 psi. I hooked up my walbro the same way, following the directions that came with it (except mine came from CTS Turbo) and setting it up to pull through the filter. I spent weeks trying to track down the problem, and never even considered the fuel pump until i read this. I immediately went out and swapped the lines and the car is pulling like a demon now at 18 psi with no sign of bucking anywhere. 














for you

Glad it worked out for you too http://****************.com/smile/emthup.gif I worked on solving the bucking problem for a month but all that hard work was quickly forgotten as soon as that first test drive at 19 psi with no bucking


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## BMAN (Jun 9, 1999)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (BMAN)*

Just to make one thing clear C2 didn't void the warranty and did send me a new one free of charge http://****************.com/smile/emthup.gif


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## gtimitch (Nov 20, 2006)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (BMAN)*

Help me understand exactly what you have done to correct your problem. I have a simple diagram I slapped together because I can't really tell if that is your filter or a pump -- Have a look and please tell what you have done....Thanks


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## pubahs (Apr 2, 2002)

B


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## gtimitch (Nov 20, 2006)

*Re: (pubahs)*

That makes sense, thanks.


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## cifdig (Jun 4, 2005)

i changed mine as well it makes a big difference,, thx


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## BMAN (Jun 9, 1999)

*Re: Do You Guys Run Your In-Line Walbro Before Or After The Fuel Pump? (gtimitch)*


_Quote, originally posted by *gtimitch* »_Help me understand exactly what you have done to correct your problem. I have a simple diagram I slapped together because I can't really tell if that is your filter or a pump -- Have a look and please tell what you have done....Thanks










Yes, B is correct nice art work


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## jhayesvw (Oct 3, 2001)

*Re: (cifdig)*


_Quote, originally posted by *cifdig* »_i changed mine as well it makes a big difference,, thx

what is the difference that was made?
i see that you guys have moved the pump to BEFORE the filter, thus PUSHING through the filter.
but what gains were made?


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## BMAN (Jun 9, 1999)

*Re: (jhayesvw)*

Well for me I never could get the car to stop bucking with more then 10 psi. As soon as I had the in-line pump installed to push the fuel thru the filter all my bucking issues went away and I'm now running 19 psi.


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## joshisapunk (Oct 1, 2004)

what he said^^ i had the same symptoms/results


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## EuroSport98 (Sep 25, 2001)

*Re: (joshisapunk)*

Did you guys happen to take this opportunity to replace the fuel filter while you were at it? Sounds to me like your fuel filters are starting to get clogged and thus by putting the in-line pump before it, it's forcing the the fuel right through it.


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## BMAN (Jun 9, 1999)

*Re: (EuroSport98)*

Sure did http://****************.com/smile/emthup.gif


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## PapioGXL (Jun 3, 2008)

*FV-QR*


_Quote, originally posted by *EuroSport98* »_Did you guys happen to take this opportunity to replace the fuel filter while you were at it? Sounds to me like your fuel filters are starting to get clogged and thus by putting the in-line pump before it, it's forcing the the fuel right through it. 


I'd like to see the pressure drop across the filter on the cars that had the bucking issue.


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## joshisapunk (Oct 1, 2004)

*Re: (EuroSport98)*


_Quote, originally posted by *EuroSport98* »_Did you guys happen to take this opportunity to replace the fuel filter while you were at it? Sounds to me like your fuel filters are starting to get clogged and thus by putting the in-line pump before it, it's forcing the the fuel right through it. 

I changed my filter the first time i hooked up the walbro and i had symptoms from the first time the car was run with the turbo setup and aux fuel pump, so the filter was not slowly getting clogged.
OEM filter of course.


_Modified by joshisapunk at 4:37 PM 9-25-2009_


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## TBT-Syncro (Apr 28, 2001)

*Re: (joshisapunk)*

i push through my fuel filter, and dont have any problems.


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## PjS860ct (Dec 22, 2002)

*Re: (TBT-Syncro)*

sorry to hijack... but just a thought/// anybody tried putting 2 walbros? 1 before and 1 after the filter? will that support higher power levels? or run richer?
thanks
paolo


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## BMAN (Jun 9, 1999)

*Re: (TBT-Syncro)*


_Quote, originally posted by *TBT-Syncro* »_i push through my fuel filter, and dont have any problems.

Yes, pushing thru the filter is correct I was told to pull thru and that's why it was bucking.


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## TBT-Syncro (Apr 28, 2001)

*Re: (PjS860ct)*


_Quote, originally posted by *PjS860ct* »_sorry to hijack... but just a thought/// anybody tried putting 2 walbros? 1 before and 1 after the filter? will that support higher power levels? or run richer?
thanks
paolo









will not run richer, and will not support higher horsepower.


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## PjS860ct (Dec 22, 2002)

*Re: (TBT-Syncro)*

what will support higher power level? stock pump > teed to 2 seperate pumps > filter > injectors?


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## TBT-Syncro (Apr 28, 2001)

*Re: (BMAN)*


_Quote, originally posted by *BMAN* »_
Yes, pushing thru the filter is correct I was told to pull thru and that's why it was bucking.

there is no reasoning why pulling through would cause bucking. the pump is always pumping vastly more fuel than is needed, and this would only be a problem if it wasnt able to maintain base fuel pressure (which is not the case at all).


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## SlammedGolfIII (Nov 18, 2003)

*Re: (TBT-Syncro)*


_Quote, originally posted by *TBT-Syncro* »_
there is no reasoning why pulling through would cause bucking. the pump is always pumping vastly more fuel than is needed, and this would only be a problem if it wasnt able to maintain base fuel pressure (which is not the case at all).

Thats what I was thinking.......theres such a massive amount of fuel being pumped and return because its not used.... I dont see how it could really make much of a difference.....On the other hand though, I have my bosch 044 pulling through my filter and I have had some breaking up when coming into boost once I get up above 10 psi......It would blow my mind if it really would make a difference.


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## joshisapunk (Oct 1, 2004)

*Re: (TBT-Syncro)*


_Quote, originally posted by *TBT-Syncro* »_
there is no reasoning why pulling through would cause bucking. the pump is always pumping vastly more fuel than is needed, and this would only be a problem if it wasnt able to maintain base fuel pressure (which is not the case at all).

it may not make sense, but changing from pull to push made all the difference in my car. http://****************.com/smile/emthup.gif


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## slc92 (Feb 9, 2005)

*Re: (joshisapunk)*

As per C2 my Walbro is pre fuel filter w/ no issues. They said it will help "stabilize" fuel pressure and help prevent particles in my injectors should the pump fail.


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## BMAN (Jun 9, 1999)

*Re: (slc92)*

Trust me you want the fuel to push thru the filter. I've tried everything to fix the bucking issue when I had the pump pulling the fuel thru the filter with no luck. As soon as I had it pushing thru the bucking stopped.


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## slc92 (Feb 9, 2005)

*Re: (BMAN)*


_Quote, originally posted by *BMAN* »_Trust me you want the fuel to push thru the filter. I've tried everything to fix the bucking issue when I had the pump pulling the fuel thru the filter with no luck. As soon as I had it pushing thru the bucking stopped.


Good to know. Way to figure out the issue. I'm just glad I had it that way from the beginning.


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## BMAN (Jun 9, 1999)

*Re: (slc92)*

I can't take credit for the fix. I sent Chris at C2 a picture of my setup and he said it was wrong. He told me I needed the fuel to push thru the filter to fix the bucking problem I had http://****************.com/smile/emthup.gif


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## slc92 (Feb 9, 2005)

*Re: (BMAN)*


_Quote, originally posted by *BMAN* »_I can't take credit for the fix. I sent Chris at C2 a picture of my setup and he said it was wrong. He told me I needed the fuel to push thru the filter to fix the bucking problem I had http://****************.com/smile/emthup.gif 

What setup are you running? Tune? Compression?
Gonna swap the Corrado over to obd2 this winter and I'm leaning toward 8.5:1 w/ the 42# setup. I've heard nothing but good things.


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## BMAN (Jun 9, 1999)

*Re: (slc92)*


_Quote, originally posted by *slc92* »_
What setup are you running? Tune? Compression?
Gonna swap the Corrado over to obd2 this winter and I'm leaning toward 8.5:1 w/ the 42# setup. I've heard nothing but good things.

-Forged JE Pistons
- Forge 007 Diverter Valve
- C2 Motorsports Low Compression 9.0:1 Headgasket
- C2 42 PSI Injectors
- ARP Head Studs
And to handle the power
- Kraftswerk 5-Speed Transmssion
- Quaife Limited-Slip Differential
- Spec Stage 3 Clutch
- Autotech Lightened Flywheel
- Dieselgeek Short Shifter


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## blue98jettavr6 (Mar 19, 2001)

*Re: (BMAN)*


_Quote, originally posted by *BMAN* »_
-Forged JE Pistons
- Forge 007 Diverter Valve
- C2 Motorsports Low Compression 9.0:1 Headgasket
- C2 42 PSI Injectors
- ARP Head Studs
And to handle the power
- Kraftswerk 5-Speed Transmssion
- Quaife Limited-Slip Differential
- Spec Stage 3 Clutch
- Autotech Lightened Flywheel
- Dieselgeek Short Shifter 

Bman what is the CR of the JE piston (I'm assuming stock)? what head gasket are you using?


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## BMAN (Jun 9, 1999)

*Re: (blue98jettavr6)*


_Quote, originally posted by *blue98jettavr6* »_
Bman what is the CR of the JE piston (I'm assuming stock)? what head gasket are you using?

Mine is now 3.0L and I use C2 Motorsports 9.0:1 Headgasket.


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## pimS (Jan 7, 2009)

I think i'm gonna switch it around this weekend, i've got mine after the filter at the moment.
See if i notice any difference


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## jhayesvw (Oct 3, 2001)

*Re: (pimS)*

im going to do a before and after in my buddy daves car.
his car has an odd stumble to it. i will drive it, check for the stumble and then see if the pump is "wrong", then fix it if it is then drive it again.
hopefully that will help reinforce this push through stuff.
i agree with TBT that the pump SHOULD push way more fuel than is needed, but hell, the observations from BMAN and others tell a different story.


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## slc92 (Feb 9, 2005)

*Re: (jhayesvw)*

Just an FYI, older Volvo's use a two pump system. The fuel filter is after the in-line. In other words it goes:
In-tank pump- In-line pump- Fuel filter-Fuel rail


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## slc92 (Feb 9, 2005)

*Re: (BMAN)*


_Quote, originally posted by *BMAN* »_
Mine is now 3.0L and I use C2 Motorsports 9.0:1 Headgasket.

What management/software? I'm assuming C2 obd2 42#.


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## BMAN (Jun 9, 1999)

*Re: (slc92)*


_Quote, originally posted by *slc92* »_
What management/software? I'm assuming C2 obd2 42#.


Yes


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## slc92 (Feb 9, 2005)

*Re: (BMAN)*


_Quote, originally posted by *BMAN* »_
Yes

How's the driveability? A/F ratio? After the in-line fix of course.


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## SlammedGolfIII (Nov 18, 2003)

*Re: (slc92)*

This still totally blows my mind just because of the amount of unused fuel that returns to the tank either way......but im gonna try it anyway..... http://****************.com/smile/emthup.gif


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## jhayesvw (Oct 3, 2001)

*Re: (SlammedGolfIII)*

yeah. it makes no sense, but if its working, its working.
dave didnt come over so i didnt get a chance to mess with his.


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## BMAN (Jun 9, 1999)

*Re: (slc92)*


_Quote, originally posted by *slc92* »_
How's the driveability? A/F ratio? After the in-line fix of course.

Perfect, pulls real hard and smooth. My air/fuel readings under full boost is 11.5


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