1/4 or 5/16 return line? - JeepForum.com
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post #1 of 6 Old 09-10-2012, 08:20 PM Thread Starter
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1986 CJ7 
Join Date: Apr 2008
Location: oakdale
Posts: 64
1/4 or 5/16 return line?

The nipple for the return fuel line is 5/16" on the TBI, but the return line is 1/4". I have read quite a few reports that say, contrary to what some believe, using the stock 1/4" return line caused no issues. Since the nipple for the return line on the Howell kit is 5/16", I have a few issues:

1) I am having a lot of trouble finding an adapter from 1/4 to 5/16. The more I look, the more I wonder if maybe they are hard to find because it wouldn't be a good idea to have one. Anyone know if they are made?

2) Anyone have ideas on where to purchase the return line, that is if I decide to replace the whole return with 5/16? I really don't want to spend a lot of money where I don't really need to. I would rather spend the money on something else I really need, rather than changing the line if I don't really need to. If I go this route, then #1 above would still apply (for the sending unit side of the hose).

3) If you have a Howell with stock return, how did you attach yours?

Thank you.

Year/Model: '86 CJ7 - Engine: 258 I-6 - Lift: Pro Comp 4" - Tires: 33X12.5 - Nuttered - Team Rush'd - Howell TBI
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post #2 of 6 Old 09-10-2012, 09:36 PM
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1930 VJ 
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Location: Wyoming
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I do not have Howell but just installed an AFI system which is the same thing . .. I used the OEM 1/4" line.. As I recall I used a 5'16" hose and just clamped it tight with a small hose clamp.. The return side as i recall only sees about 4 lbs pressure. I also installed an in-tank pump after numerous vapor lock issues.. . Other than pinching the return line at the tank I had no other issues..
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post #3 of 6 Old 09-10-2012, 10:43 PM
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1981 CJ7 
Join Date: Jul 2009
Location: Bali
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The hose for the stock return line is 0.25" ID. In other words the outside of the Tube going back to the tank is 0.25" OD.

You could use 0.25" ID hose to connect and it may be possible to work it over the nipple, it depends on the hose material. Alternatively you could look at the amount of flare on the Tube.

BagusJeep lives in Bali.

1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
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post #4 of 6 Old 09-11-2012, 06:08 AM Thread Starter
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1986 CJ7 
Join Date: Apr 2008
Location: oakdale
Posts: 64
I think I'm gonna try and use 5/16 line and see if it will clamp down on it. I was hoping there may be a better solution, but maybe that will work.

Year/Model: '86 CJ7 - Engine: 258 I-6 - Lift: Pro Comp 4" - Tires: 33X12.5 - Nuttered - Team Rush'd - Howell TBI
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post #5 of 6 Old 09-11-2012, 01:01 PM
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1984 CJ8 
Join Date: Jul 2005
Posts: 198
I had a hell of a time finding correct adapters between the rubber fuel lines and the hard lines on my Jeep. The automotive industry really likes using 1/16" increments for there stuff. Good examples are 5/16 fuel lines and 9/16 suspension bolts. Most hardware stores carry a small inventory at those sizes but there is stuff out there that exists.

I found the company below that makes splice adapters, but I thought that was a little on the ghetto side.

I ended up using Mcmaster Carr and ordered a 1/4" compression fitting to female NPT and then ordered a male NPT to the correct barb that I needed. It turned really clean and it gives you a lot of options for going with other tube and hose combinations. It also keeps everything looking the same.

Ohh and the 1/4" return is no problem. I ran it on my 4.3 cpi for about 6 years.
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post #6 of 6 Old 09-11-2012, 02:40 PM
1983 CJ7 
Join Date: Feb 2010
Location: Glendale,Arizona
Posts: 1,563
I've had mine on since 96 with no issues.Just clamp the 5/16 over it.Double clamp it if you have too.
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