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Fuel pumping fuel into drivers side?

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tsiawd98

20+ Year Contributor
95
12
Dec 20, 2002
Las Vegas, Nevada
I am having this issue where the fuel is being pumped into my drivers side tank, instead of being sucked into the passenger side? I had to remove my fuel tank 5 months ago, because my fuel got bad. So I decided it was time to install my a/n fuel lines. -8 feed and -6 return, The car runs great, and no leaks at all. However for some reason I can put 5 gallons in the tank when it is empty, and for some reason the fuel is being pumped into the drivers side?

I cannot register this car in vegas, so unfortunatly it sits for the time being. After I fill it up with gas and start the car 2-3 times later to get the engine up to temp, and when I drive it in the neighborhood. The car will not want to start, like it is out of fuel. I pulled the pump and then the drivers side pickup, and all the gas ends up in the drivers side tank, while the fuel pump side is empty? And I made sure that the y connection is not bottoming out in the fuel tank.

Anyone might have an idea as to what or why this is happening? I checked the lines and they are airtight. I have read that the return fuel line pulls fuel from the driver side by a venturi effect with the fuel coming back from the rail into the tank.

Anyhow if somebody has an answer or has dealt with this I would like some info. I have searched, and cannot find a similar problem??
 

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I am not sure if I understand that I have the siphon lines out of place? there is only a metal line at the front of the tank in between with two rubber lines at the ends that connect the the fuel pump and the fuel sender. I did find some pictures last night on 2g fuel pump hangers and found I messed up by installing the y connection backwards. I have corrected that last night, with that fixed the fuel is not pumping fast into the drivers side however it has slowed down, but still doing it.

While I was in Afghanistan back in 2012 I purchased a full blown hanger, I have not installed it yet for the reason I cannot legally drive the car here in nevada, so I just kept the supra pump along with the modified factory hanger. Now I am thinking about installing the full blown hanger to see if that might start pulling fuel from the other side?? A friend at work knows someone that will hook me up on the emission test. So I plan on getting the car perfect mechanically, so later this year after the 100 deg. temps have gone I can then start paying insurance and register the car.

Thank you for replying
 

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I am having this issue where the fuel is being pumped into my drivers side tank, instead of being sucked into the passenger side? I had to remove my fuel tank 5 months ago, because my fuel got bad. So I decided it was time to install my a/n fuel lines. -8 feed and -6 return, The car runs great, and no leaks at all. However for some reason I can put 5 gallons in the tank when it is empty, and for some reason the fuel is being pumped into the drivers side?

I cannot register this car in vegas, so unfortunatly it sits for the time being. After I fill it up with gas and start the car 2-3 times later to get the engine up to temp, and when I drive it in the neighborhood. The car will not want to start, like it is out of fuel. I pulled the pump and then the drivers side pickup, and all the gas ends up in the drivers side tank, while the fuel pump side is empty? And I made sure that the y connection is not bottoming out in the fuel tank.

Anyone might have an idea as to what or why this is happening? I checked the lines and they are airtight. I have read that the return fuel line pulls fuel from the driver side by a venturi effect with the fuel coming back from the rail into the tank.

Anyhow if somebody has an answer or has dealt with this I would like some info. I have searched, and cannot find a similar problem??

I have had this problem when I upp'd my feed/return as you did. With a high flow pump and upp'd feed/return the fuel is flowing faster than the siphon can keep up.

I would fill it up and run it till my gauge said empty, but it would only take about a half a tank or less to fill back up. So as you said the DS of the fuel tank isn't siphoning over to the PS side where the pump is.

To fix you need to drill out the siphon to a slightly larger size. Not sure what size I drilled mine too, but if you search on here for siphon drilling im sure you'll find it like I did.

Driling out the siphon 100% fixes that problem.

Here are some pic's of the siphon you need to drill.

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@tsiawd98 Actually your stock siphon is missing. That is very likely your problem....its not siphoning at all.

If the siphon is to larger it wont do what its supposed to do and if its to small it will not do it fast enough.

Where's the stock siphon in this pic?

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I still have the stock siphon, but I installed a return line bulkhead connection at first, until I realized that you can buy steel a/n bungs. the return line is a bulkead, and the feed line I got the a/n fitting and had it welded. I used the "siphon" connection from my full blown hanger instead thinking it would work. I am now thinking that I may have messed this up from the get go. should have done more research before I started hacking it up, and just bought steel a/n fittings. I wonder if there is any way I can somehow reinstall the factory siphon back onto the pump?? I do remember that factory return metal line went directly into the siphon with a oring on the end. I do not see anyway of me fixing this? Thanks kmetiuk this is pointing me in the right direction!
 
I still have the stock siphon, but I installed a return line bulkhead connection at first, until I realized that you can buy steel a/n bungs. the return line is a bulkead, and the feed line I got the a/n fitting and had it welded. I used the "siphon" connection from my full blown hanger instead thinking it would work. I am now thinking that I may have messed this up from the get go. should have done more research before I started hacking it up, and just bought steel a/n fittings. I wonder if there is any way I can somehow reinstall the factory siphon back onto the pump?? I do remember that factory return metal line went directly into the siphon with a oring on the end. I do not see anyway of me fixing this? Thanks kmetiuk this is pointing me in the right direction!

Put the stocker siphon back on and run it.....you'll prolly still have the issue as I did.

Easy fix tho just drill the stock siphon out a bit.

I'm running a wally 400 and -6 feed/return from tank to rail and with it drilled out I have zero issues with this problem anymore.

Look at my pics....I'm using the stock siphon still.
 
So being that I cut up the factory fuel pump hangar, I cannot use the factory siphon system. Now what I did was I have a Full blown setup that was sitting around for a few years, have not had time to install it. I chose to install this to see if it would cure my issue. It did not. Same problem when the car was running at idle, it would fill up the DS of the tank very quickly and where PS would be empty? Next I decided to isolate the siphoning system of the full blown hanger and see if there is a vacuum leak anywhere, and the hose going from the top of pump housing to the DS, where the pickup is. it held a solid 15 in. vacuum on the fuel pump housing return system, and the line going over to the DS. After that I went to Ace hardware and purchased various connectors that go on the end of the return "T" circled in red. the only thing that worked was a 1/4 inch connector. That has now stopped fuel being pushed into the DS of the tank, however I do not notice that it is siphoning fuel at all to the PS?

If anyone here has the Full blown pump hangar, please let me know what you did and if you had the same issues. I have read up on this issue for a while. I found on the EVO forums of the same issue, but they don't really go into detail how they fixed it? and some DSM guys install this with no issues at all. As of right now I have 1ea 340 full blown pump installed in it. with a plug installed where the other pump would be. I am frustrated at the moment, I want to drive the car this fall/winter, but technically I only have half a gas tank to play with before I run out of fuel. Any help would be appreciated thanks.
 

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I figured out my issue with the fuel being pumped into the drivers side of the tank. The Full Blown "y" fitting SUCKS!! It does not perform any vacuum to pull the fuel from the other side of the tank to the fuel pump side. And I called them up about this with "we have never heard of that before" I was on STM Tuned when I found the EVO suction pump. when I got it, I hooked it up to a vacuum guage and blew through it, it produced a vacuum, unlike the full blown "y" fitting. I made a makeshift gas tank with two buckets cuz I got tired of getting gas in the car everytime I pulled out the hangars. As soon as the car started, within 15-20 seconds the bucket that is suppose to be on the drivers side was empty and all fuel was transferred to the fuel pump bucket. My fuel pressure was rock solid at 42 psi and everything seems to be working correctly now. So in the future if someone gets the Full blown hangar and you run out of gas at 1/4 tank of fuel, or all the fuel is on the drivers side, get the EVO suction pump, and ditch that "y" fitting that Full blown supplies.
 

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I figured out my issue with the fuel being pumped into the drivers side of the tank. The Full Blown "y" fitting SUCKS!! It does not perform any vacuum to pull the fuel from the other side of the tank to the fuel pump side. And I called them up about this with "we have never heard of that before" I was on STM Tuned when I found the EVO suction pump. when I got it, I hooked it up to a vacuum guage and blew through it, it produced a vacuum, unlike the full blown "y" fitting. I made a makeshift gas tank with two buckets cuz I got tired of getting gas in the car everytime I pulled out the hangars. As soon as the car started, within 15-20 seconds the bucket that is suppose to be on the drivers side was empty and all fuel was transferred to the fuel pump bucket. My fuel pressure was rock solid at 42 psi and everything seems to be working correctly now. So in the future if someone gets the Full blown hangar and you run out of gas at 1/4 tank of fuel, or all the fuel is on the drivers side, get the EVO suction pump, and ditch that "y" fitting that Full blown supplies.


Awesome you figrued it out man. Good work. :)

Can you mark this thread as answered plz? Too many unanswered threads out there.

So does the suction pump actively pump from one side to the other or does it just rely on vacuum?
 
No modification required. installed EVO fuel pump "y" fitting. and works good.
 

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I figured out my issue with the fuel being pumped into the drivers side of the tank. The Full Blown "y" fitting SUCKS!! It does not perform any vacuum to pull the fuel from the other side of the tank to the fuel pump side. And I called them up about this with "we have never heard of that before" I was on STM Tuned when I found the EVO suction pump. when I got it, I hooked it up to a vacuum guage and blew through it, it produced a vacuum, unlike the full blown "y" fitting. I made a makeshift gas tank with two buckets cuz I got tired of getting gas in the car everytime I pulled out the hangars. As soon as the car started, within 15-20 seconds the bucket that is suppose to be on the drivers side was empty and all fuel was transferred to the fuel pump bucket. My fuel pressure was rock solid at 42 psi and everything seems to be working correctly now. So in the future if someone gets the Full blown hangar and you run out of gas at 1/4 tank of fuel, or all the fuel is on the drivers side, get the EVO suction pump, and ditch that "y" fitting that Full blown supplies.
I’m not having this problem using the full blown siphon. You have to make sure all the parts of it are tight since it is a few parts put together to form the y. If there is a slight leak I believe that is what will cause your problem you had. Everything has to be tight even if you have to dissamble it and put thread sealer.
 
I’m not having this problem using the full blown siphon. You have to make sure all the parts of it are tight since it is a few parts put together to form the y. If there is a slight leak I believe that is what will cause your problem you had. Everything has to be tight even if you have to dissamble it and put thread sealer.
I stand corrected. I am having the same issue. Guess I will have to buy the Evo siphon as well. Drivers side tank full passenger side totally empty. Will update once part arrives. I thought I had two bad pumps but tank PS side was empty as reported.
 
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