The 1947 - Present Chevrolet & GMC Truck Message Board Network

The 1947 - Present Chevrolet & GMC Truck Message Board Network (https://67-72chevytrucks.com/vboard/index.php)
-   The 1967 - 1972 Chevrolet & GMC Pickups Message Board (https://67-72chevytrucks.com/vboard/forumdisplay.php?f=3)
-   -   fuel line return question (https://67-72chevytrucks.com/vboard/showthread.php?t=105459)

franko72 05-24-2004 06:53 PM

fuel line return question
 
I bought my truck with the return line from the fuel pump plugged at the pump .It is also plugged off just below the gas tank.It it a 402 BB with a quadrajet, should I reconnect the return line from the pump to the tank.Are there any performance problems that could develope? What is the purpose of the return line anyway.could this be the reason why my truck doesnt come out of the hole strong?

68speedalert 05-25-2004 11:17 PM

The return line is to return fuel back to the tank..................duh. Just kidding. Your carb only uses a small amount of the fuel the pump puts out under normal driving. What can happen without the return is the fuel sitting in the line waiting to go to the carb can boil in the hose and cause a vapor lock. The return line lets the fuel circulate and hopefully not boil.

No, the line disconnected has no bearing on your hole-shot. if your truck jumps and then sags or cuts out, it could be the fuel pump. Look closer to base timing, mechanical advance, four barrels opening up. Maybe find what your rear-end gear ratio is. If it's something like 3.08s, there is the problem.

franko72 05-26-2004 04:55 PM

the rear end ratio and type is a dana 70 3:54 , it has a 10 5/8" ring gear.Do you think that this is why it doesnt do a good hole shot?

Cruiser71 05-26-2004 07:41 PM

I have found that all the 1/2 tons I owned had return lines and my 3/4's didn't. I think it may have to do with emissions. i could be wrong.

68speedalert 05-26-2004 07:43 PM

I'm certainly not an expert on rear dif questions. you probably have a large tire as well since this is obviously a 3/4 ton. All this coupled with a probable th400 auto trans could be it. I'm not sure but I don't think those tranny's have a low first gear.

A gear like a 3.73 or 4.11's do make a big difference.

Did you try manually putting the shifter in 1st to see if there is any difference?

franko72 05-26-2004 08:57 PM

yes it is a 3/4 ton with a 400 turbo trans.I also have 16.5 " tires. I can pull it down in 1st gear when I have a little momentum and it will bark the tires, just not from a complete standstill


All times are GMT -4. The time now is 11:51 AM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2025, vBulletin Solutions Inc.
Copyright 1997-2025 67-72chevytrucks.com