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Location:
Brisbane
Registered:
March 2004
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RA40/18RG return lines
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Thu, 20 May 2004 10:09
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Hiya,
I went round to Ben's (people100) place last weekend so he could have a quick look at what's up with my engine, and he pointed out a few things i didn't know to look for. Number one thing is the lack of a return line. I had a look through the Haynes guide and it does show the stock electric fuel pump has a return line connection, though i don't know if it's hooked up. In the engine bay there's a pipe right next to the feed line that's just sitting there connected to nothing, which i guess is the return?
What would be the procedure involved in hooking it back up? I guess i'd have to open the fuel tank to make sure it's connected at that end - can you do that without draining the tank? Do i need a static electricity strap or is that the computer person in me talking? Once i've checked that end, where would i insert a return hose? Directly to the feed line at the end of the carbs, or to the feed line between them, or is there somewhere completely different?
Thanks in advance guys...
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Location:
Rocklea qld
Registered:
February 2003
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Re: RA40/18RG return lines
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Thu, 20 May 2004 10:30
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Firstly the ra40 doesnt come out standrad with a electric fuel pump...It had a 18rc with a mechanical pump...U have 2 options....1 is just leave it as phil (Mr dohc) also has no return on his engine....or remove the elec full pump and hook the mechanicalk one ofn the engine back up which gives u a return line to hook up...Or leave the electric pump and put a t piece in just before the carbies so you can hook to your return line...easy as that really...but make sure it is hooked up at the fuel tanl...
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Location:
Brisbane
Registered:
March 2004
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Re: RA40/18RG return lines
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Thu, 20 May 2004 10:52
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Cool, that makes a bit more sense. I think the Haynes manuals tend to the American models which kinda screws up figuring out what is and isn't stock sometimes. So if i put in a T piece before the carbs and connect it up... will i need some kind of pressure regulator or something to stop it just going round in a circle and never hitting the carbs?
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Location:
Brisbane
Registered:
February 2003
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Re: RA40/18RG return lines
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Thu, 20 May 2004 14:58
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RA40 should have three line (in total) from tank to engine bay.
-main line sucks petrol from bottom of tank
-return line returns excess fuel to tank near top of tank
-breather line that feeds fumes from very top of tank to the charcoal canister
and it's important to get the right return (if you mix vent & return lines and the tanks is full of fuel, it won't vent excess fumes/pressure correctly - particularly if your cap doesn't have a pressure release valve...
from my exp. the haynes manuals are mostly bullshit...
a simple t-pieece with a 1-2mm restrictor in the port going to the return line might suffice as a simple pressure regulator ...
but i'm sure oldcorrolla's said in another fuel-pump thread that some low-pressure electric pumps have pressure regulator builtin...
if you want a safe solution, get a fuel pressure regulator...
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I supported Toymods
Location:
I renounced punctuation
Registered:
May 2002
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Re: RA40/18RG return lines
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Thu, 20 May 2004 16:51
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Or....
you could do what I did.
A Charger fuel filter has a third outlet for the return. You put a fuel pressure guage in the main line to the carbs and measure fuel pressure. If it is too high, you just drill out the return line orifice till it puts the fuel pressure into the right range.
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Location:
Melbourne
Registered:
May 2002
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Re: RA40/18RG return lines
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Fri, 21 May 2004 00:22
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by the way RA40's do have the wiring for the fuel pump still going to the back, no need to string together little thin bits of wire and tie them to the fuel line (i have seen this done!) the wire is easly found in drivers side kick panel
Allan
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Location:
Brisbane
Registered:
March 2004
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Re: RA40/18RG return lines
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Fri, 21 May 2004 08:26
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Well i checked under the car after work today and the electronic fuel pump is definitely hooked up, and it's not a submergible one. I tried to follow the pipes under the car, but i couldn't see it easily (don't have anything to lift the car up with). There were four pipes heading in the direction of the fuel tank. Can i assume the return line is permanently attached to the fuel tank, so i don't really need to check the connection there? If so... RA40 owners please help  In the engine bay there are two pipes coming up side-by-side on the driver side. One of those goes into a small plastic chamber and then onto the carbies, and the other is currently connected to nothing. Is that other one the return? What i'm planning is to get a T-piece and pressure regulator from Repco and hooking it up so it goes from the plastic chamber to the T-piece, where one split goes to the carbies and the other goes to the regulator and then the return. Does that sound right?
Alison
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Location:
Canberra
Registered:
February 2004
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Re: RA40/18RG return lines
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Fri, 21 May 2004 09:23
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During a super fault finding session this summer I took teh whole fuel system apart in my ra40. There should be three pipes running to the tank. two from the drivers side for the send and return and another from the passengers for the charcoal canister. The three of them come together and enter the tank through rubber hoses about 1cm apart. You need to check that the hose is still there for that connection. If you drop teh tank you can easily identify the lines because the send drains from the bottom of the tank and the return dumps its fuel near the top of the tank. Some previous owner had improved my fuel system by putting the fuel filter on the return line.
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Location:
Rocklea qld
Registered:
February 2003
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Re: RA40/18RG return lines
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Fri, 21 May 2004 12:43
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i dont see wha the problem is...I already established that it is a return line......Just use a t piece for now or hook the mechanical fuel pump back up
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Location:
Brisbane
Registered:
March 2004
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Re: RA40/18RG return lines
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Sun, 06 June 2004 07:53
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Thanks for all the help guys. In the end i've given up on the whole return line idea and just today put a fuel pressure regulator inline instead. Just before the carbs, set to 3psi, retuned the idle and it seems to be running pretty smoothly... Now to wait and see if i actually get more than 150km a tank!
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