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Topic: Fuel line question (Read 1910 times) previous topic - next topic

Fuel line question

On the throttle body, there are two steel fuel lines that the plastic/nylon fuel lines connect to. Which line is the input and which is the return? Also, how much pressure is in the return line?

Thanks
Cornfed85

1985 Thunderbird - 3.8 V6, C5  :ford:  :birdsmily:

Fuel line question

Reply #1 –
The fatter pipe is the supply, the thinner one is the return.

Somebody else can chime in with the fuel pressure. I don't think CFI requires a whole lot of pressure (by today's standards), and the return would be a fraction of that. I know I had a rust hole in my old 83 cfi return line, and I just cut out the bad section and replaced it with fuel-rated hose and a couple clamps. It held just fine.
CoogarXR : 1985 Cougar XR-7

Fuel line question

Reply #2 –
Quote from: Cornfed85;453350
Also, how much pressure is in the return line?
There is no way to measure it, but it should be close to zero.
The pressure at the Schrader valve on the CFI should be 39 psi. If the pressure at the valve is way high, you could suspect a blocked return line.

Fuel line question

Reply #3 –
Ok, thanks!
I accidentally broke the plastic fitting for the return line, and neither O'Reilys or AutoZone carry anything that fits. So I'm planning on putting a rubber hose on the return line and hook it up to the plastic line.
Cornfed85

1985 Thunderbird - 3.8 V6, C5  :ford:  :birdsmily:
 

Fuel line question

Reply #4 –
Take a picture of the broken part. I suspect it will be similar to fuel filter nylon clips.
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

Fuel line question

Reply #5 –
Yes it is, however, I bought two of the replacement connectors and neither of them fit. The return outlet is smaller diameter. Neither of the parts stores I went to had anything smaller.
Cornfed85

1985 Thunderbird - 3.8 V6, C5  :ford:  :birdsmily:

Fuel line question

Reply #6 –
Quote from: Cornfed85;453357
Ok, thanks!
I accidentally broke the plastic fitting for the return line, and neither O'Reilys or AutoZone carry anything that fits. So I'm planning on putting a rubber hose on the return line and hook it up to the plastic line.
A shop did this to my '85 Cougar about 15 years ago. They couldn't find (and probably didn't look very hard) a junk car to swap the whole line out so they put some rubber hose over the broken section and slapped some hose clamps on it. Worked fine for the 10+ years I had the car afterwards.

In your case, should be able to get a replacement fitting to replace the one your broke. What parts did you try?
http://www.dormanproducts.com/documents4rb/135-145QuickDisconnectBuyersGuide.pdf

I'll have to look at my car, but the 800-055 may work. Can't remember which line is which offhand. Dorman has 3/8" and 5/16" straight and 90 degree fittings, so 1 should work!