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Guest Message by DevFuse
 

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3 line fuel filter & vent line


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34 replies to this topic

#1 bobaru

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Posted 04 November 2009 - 09:53 PM

the car 82 ea81 carter-weber........ Im installing a weber ea82 intake every thing ok so far ..

now hooking up the fuel lines the filter has 3 lines

fuel in from tank (size 5/16)........fuel out to carb (5/16) .......3rd line looks like a fuel return (1/8)

do I need that 3rd line, or just plug it..............

looks like the the tank vent line runs into the charcoal canister.....T or F

Edited by bobaru, 04 November 2009 - 11:04 PM.


#2 GeneralDisorder

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Posted 05 November 2009 - 10:21 AM

Remove the stock filter and install a plain one inlet/one outlet fuel filter. You don't want or need that vapor seperator. In fact you don't need a filter in the engine bay at all as there is one back by the pump. The "filter" in then engine bay is really a vapor seperator not primarily a filter.

Remove the canister and just leave the tank vent open.

GD

#3 bobaru

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Posted 05 November 2009 - 10:24 AM

Again thank you GD

I like the Idea of the second filter will do .................
has any body ever put a filter on the vent line......... like .........http://www.grainger....A325?Pid=search

Bob

Edited by bobaru, 05 November 2009 - 11:00 AM.


#4 thornleyjacob

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Posted 27 March 2015 - 01:01 AM

Remove the stock filter and install a plain one inlet/one outlet fuel filter. You don't want or need that vapor seperator. In fact you don't need a filter in the engine bay at all as there is one back by the pump. The "filter" in then engine bay is really a vapor seperator not primarily a filter.

Remove the canister and just leave the tank vent open.

GD

 

Doing a Weber conversion and looking at my options for the engine bay fuel filter, return line, and fuel tank vent line... I like the idea of just deleting it all like you basically say here. But what happens if I am in a steep decline and the line's opening is at lower elevation than that of the gas tank; wouldn't it leak? If so, how does one stop that from happening?



#5 l75eya

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Posted 27 March 2015 - 03:03 PM

I think that would only really occur if you flipped over. I'm just speculating, but being a return line, the other end of that hose probably goes to the very top of the fuel tank.

That's really just a guess, but I do see your concern. Could probably just go back there and look.



#6 thornleyjacob

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Posted 27 March 2015 - 03:19 PM

I think that would only really occur if you flipped over. I'm just speculating, but being a return line, the other end of that hose probably goes to the very top of the fuel tank.

That's really just a guess, but I do see your concern. Could probably just go back there and look.

 

That is what I am thinking too; I cannot understand how else it would have worked originally as the charcoal canister would have flooded with fuel in the same scenario. Also, the return line is not the issue - this one we plug off. Its the fuel tank vent line that I'm worried about.



#7 mcbrat

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Posted 01 April 2015 - 11:10 AM

there's enough bends and changes in elevation in the line and such that's there's no way it would come back through the vent line in any normal circumstances if there's not a safety valve involved...



#8 beamsbox

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Posted 04 March 2017 - 12:55 PM

Another thread revival:

 

Under the hood, which is the vent line and which is the return line? Anyone got pics? I have the triple-nipple fuel filter/separator as well, with another single in single out on hand. I did the original weber install a year or so ago, and never was sure about shich was the vent.

 

But, I've been noticing the tank pressurizing and would like to put a small filter on the tank vent line. Can someone please show me where that might be?



#9 Naked Buell

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Posted 04 March 2017 - 01:17 PM

IMAG05481.jpg

 

This line goes to the carb.

 

IMAG05471.jpg

 

This is your return.

The other one on the bottom of the filter on the left is your supply.



#10 beamsbox

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Posted 04 March 2017 - 01:37 PM

So where is the tank vent line?



#11 Naked Buell

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Posted 04 March 2017 - 02:13 PM

This car is an 88 Rx that i converted to an ea81 with the weber, the vent line is under the master cylinder, right above the frame rail. Mine was pressurizing too causing flooding once I shut her off, but then I had the vent plugged. I was told to unplug and put a lawn mower fuel filter on the end. She has been fine since. 



#12 beamsbox

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Posted 04 March 2017 - 02:32 PM

I'm gonna go take pics to share. Thx for your help, Buell. I know I got something wrong.



#13 beamsbox

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Posted 04 March 2017 - 07:02 PM

Ok so here are some pics of the current setup.

 

IMG_20170304_115756.jpg

Here's an overview of all the hoses.

 

IMG_20170304_115542.jpgSide view of the filter.

 

 

The top line goes down, through an F fitting that just never got removed, and which is capped on one port, then is routed to the left of the compartment. The left hose is the supply which is routed down and behind to the higher of two ports on the firewall. The right hose is connected directly to the carb.

 

IMG_20170304_115658.jpg

Good view of where the top hose goes,  Is this the vent line coming through the firewall?

 

IMG_20170304_115636.jpg

And here's the other two firewall locations.

 

IMG_20170304_115604.jpg

A view of all three firewall ports, the supply line, and the 'F' fitting  that I believe used to be routed to the vapor canister.

 

IMG_20170304_115734.jpg

And the Weber connections.

 

Is this not correct?



#14 Naked Buell

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Posted 04 March 2017 - 08:13 PM

Okay, I have been studying your pics and I agree with GD. So; you take your supply into your filter; out of filter to your carb; and the top of the filter is your return; leave the other one open. You should be good then. So you have them crossed. Your red mark is good. Blue dot from filter should go right to carb. Delete blue. Green dot on top of filter goes to yellow return into firewall.

The canister is just a maze leading to nowhere.  



#15 beamsbox

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Posted 04 March 2017 - 10:04 PM

Thought I already posted this, apparently not. But here's what I've come up with:

 

Fuel%20Lines.jpg

 

Looks like in my current setup, I've got the return going to the 'Evaporation Tube' which I would assume is the vent.

 

So, I re-routed, the return line and the top of the filter to meet at the 'F Fitting' (Item 28), then on through the firewall on the port to the left of the master cylinder. The rest looks good.



#16 beamsbox

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Posted 04 March 2017 - 10:33 PM

Yup, no canister anymore. Naked Buell, thanks for takin the time to help me sort this out. It's been running a little sporadic lately, like a random fuel starvation or small vacuum leak. I did discover that the vacuum advance is shot, allowing air through the diaphragm, so that could be the issue I started with, got that plugged for now, on the engine side. I'm not sure if the vacuum advance ever worked though. I guess we'll get there one step at a time. Your input is appreciated.

 

the top of the filter is your return; leave the other one open.

 

I routed the top of the Filter to the green line F, as shown in the pic. Leave which one open?

 

Blue dot from filter should go right to carb. Delete blue.

 

This seems contradictory... Delete Blue? Blue is my main supply... It is currently routed direct form carb to fuel inlet (via the Y at the inlet fitting). 

 

Green dot on top of filter goes to yellow return into firewall.

 

I think the yellow is the vent... but could def be wrong... for now that's how I have it. Coming out of the firewall I put a short hose and a small conical air filter.

 

 

Blue dot from filter should go right to carb. Delete blue.



#17 Naked Buell

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Posted 05 March 2017 - 10:38 AM

Go back to your post #13, your first pic; The red dot and yellow dot is your supply and return. Obviously the bigger of the two is the supply. On the filter you will find an arrow showing you which way the fuel is suppose to flow. So your red dot from the firewall to the filter seems right.

 

Being that you got rid of the canister, it will be just like mine and you will have ones now you don't use.

 

I changed my fitting at the carb to have only one hose.

 

Your blue dot coming from the filter to the carb is ok. Just cap the yellow one at the carb or do what I did and change it to one hose fitting. 

 

The green on the top of the filter is your return which should go to the yellow back into the firewall which is the one next to the red. 

 

The green on the firewall leave open. The others you plug. What I did on mine was delete the pipe system due to too many plugs. I did away with it just have the fuels lines you need; much cleaner and less confusing. 



#18 beamsbox

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Posted 05 March 2017 - 01:18 PM

Sounds good I can handle that. It does look like the book is calling the green the return though, whereas your saying it's the yellow. That would make the green the vent, I can move the filter to there.

#19 Naked Buell

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Posted 05 March 2017 - 04:13 PM

So in simple terms; supply comes to the filter and leaves the filter to the carb. The outlet on top of the filter is excess which then goes to the return. The vent you leave open. (That is the one to the left of the Master cylinder when looking at it)



#20 beamsbox

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Posted 05 March 2017 - 05:47 PM

Copy that. Should be good now then.

 

IMG_20170305_134205.jpg

 

IMG_20170305_134215.jpg

 

IMG_20170305_134227.jpg

 

So, I understand the supply, return, etc. But what I'm trying to say is the pic I shared above, the pic from the FSM, (which I've highlighted to match the coloring of my original routing), they are calling the green lines the return, which would be the line you just told me to leave open. And they are calling the yellow lines the 'evaporation tube' (item 14, forgot to highlight that), which we just routed the return to. Evaporation sounds like vent to me, which would mean that now we both have the vent and the return crossed. No?

 

I'm not tryin to mess with ya, just trying to understand, so please don't take it the wrong way. Totally appreciate your help. Hey, if it works, it works.



#21 beamsbox

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Posted 14 March 2017 - 07:47 PM

Alright... so... that didn't work out too well for me. Today I got home and smelled a lot of gas after exiting the vehicle. With my arms full, I walked past the rear and noticed a long path of gas on the road... dangit. After relieving my arms, I went back out and popped the hood only to find  gasoline dribbling (at not a very slow pace) out of the silver air filter that I installed the other day.

 

I then ran over to the gas cap and purged the system, releasing a bunch (if not more than before) of built up pressure. And the dripping gas stopped under the hood. So, it seems that that line is connected to a low spot in the tank, otherwise, it wouldn't have pushed gas up and out.

 

Next, I moved crossed (uncrossed) the lines, attaching the air filter to the line that comes through the firewall directly under the supply line and I routed the top of the fuel filter to where the air filter was located (to the left of the brake booster).

 

I guess we'll watch it and see what happens. Not too sure how optimistic I am, as this is pretty much the same setup I had before, only with the extra parts removed... though now there is no return directly at the carb. Wish me luck.


Edited by beamsbox, 14 March 2017 - 07:48 PM.


#22 GeneralDisorder

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Posted 15 March 2017 - 12:53 AM

Yellow is your vent/evap. Green is the fuel return.

Use a two port filter on the supply. Do nothing with the vent, and optionally use the return though it is not needed with carb pump pressure. You can leave both of them open.

GD

Edited by GeneralDisorder, 15 March 2017 - 12:57 AM.


#23 beamsbox

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Posted 15 March 2017 - 01:51 AM

Damn. That's what I figured via the fsm. Live n learn, live and learn. I did pickup a two port fuel filter, so I'll go that route soon.

Thx, GD.

#24 beamsbox

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Posted 16 March 2017 - 08:56 AM

Aw man.... so... yesterday I installed the two-port fuel filter under the hood and removed the unnecessary hoses... 

 

Same thing!

 

Still have pressure buildup in the fuel tank. And now it is blowing out the return. lol.

 

 

Anyone got any great ideas? Would this be a clogged vent line?



#25 Naked Buell

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Posted 16 March 2017 - 09:58 AM

Crazy, now I am confused.  ^_^ But GD does know his stuff. I would double check and now I am going to double check mine.  :)






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