Team Chevelle banner

Dan's 70 SS 396 Fuel Pump

2K views 10 replies 9 participants last post by  Jim Mac 
#1 ·
Hi Chevelle Fans,

Its summertime almost and I thought I was solid to go this season and we are having fuel issues with our numbers matching stock SS 396.

History: I drove it 2 weeks ago and drove about 40 miles with zero issues. Took it for a "Sunday" drive... nothing fast or racing like. Parked the car in her climate controlled garage and covered it. This week I went to go use it and the motor just cranked over and over with nothing. Checked spark and all good... then pulled fuel line at the carb after attempting to manual mist the carb and not see or hear any fuel... pulled the fuel filter in the stock carb and its dry! No fuel... also:* Poured a 1/4 cup of fuel in the carb and she fired right off.

So then I went to the stock AC Delco fuel pump and pulled it and it appeared to be making the correct sucking and pumping noise as I put it in a vise and exercised it, pulled and inspected the shaft that strikes the fuel pump and it is fully intact and looks appropriate to me. So off to ORiellys and purchased an after market fuel pump... closest unit I could get do to Covid 19 mess. Installed it and the same result... No fuel. I do have fuel from the tank to the fuel pump but as an extra I even blew out the fuel lines to make certain. Re installed the fuel pump again with correct vent line (smaller one) going back to the tank and supply line to the pump. Same result...

What am I missing? Don't tell me the lobe that drives the shaft just went to heck and I need to tear into the motor? I am I installing the fuel pump incorrectly? I did do a series of crank tests with the fuel pump off to see if the position of the push rod changed after a series of cranks and it would appear not.

Help!
 
See less See more
#3 ·
Check the short piece of hose between the sending unit and the line going to the front of the car. If it's dry rotted and cracked it will suck air and cause problems.
 
#4 ·
A couple other items to check.
Make sure the hose from the line on the frame to the pump inlet is not in any way kinked or even forced to a point that will compromise the diameter of the hose. If it is, when the motor gets hot it could get sucked closed by the pump. Also, I just had a similar situation which ended up being a bad pump which was not that old. The arm was not engaging the pump until 3/8 of inch of travel. The cam lobe is barely more than that. I purchased another aftermarket pump and it was no better. Then I purchased a A/C Delco and it had zero play in it. Problem solved.
Good luck.
 
#5 ·
Just an Idea. When you get it running. install a metal fuel filter in the back at the tank. I do not like messin with the ( inside) fuel filter in the 7040205 or 04. Both of my 70s have metal fuel filters in the back.---- I, NO PUT FINGERS on Q-Jet. In my lifetime, I have had issues with Q-Jets,,, Changing filters......:crying: I have good luck with my Q-Jets, By keeping my paws OFF of them!
Bob
 
#6 ·
I do something similar to what Bob is saying. If the tank is out, I remove the filter sock off the pickup and put a remote filter outside of the tank. That way it is NEVER the in tank filter and I never have to wonder if it is. Just swap out the remote filter and go.
 
  • Like
Reactions: 427L88
#8 ·
That I one of the first things I did. During the restoration, I used the Org. fuel gauge and it went in the tank " WITH OUT " the sock in place. So far with the metal fuel filter sitting on top of the tank, NO SOCK--- NO touching the Q-Jet--- NO Fuel issues.---:thumbsup:
Bob
 
  • Like
Reactions: RealRed70
#9 ·
Welcome Dan, to Team Chevelle.....:waving:

If you have checked everything from the line coming out of the fuel tank forward, and it's all working properly, then I would agree with others that the problem is inside the tank. That sock may be plugged or damaged.

The other thing you could try is installing a temporary electric fuel pump between the fuel line from the tank and the carb. Bypass the mechanical pump just to see if the engine starts and runs. If it does, then you know the problem is with the stock fuel pump or the push rod that activates it. You can buy those little electric fuel pumps for $12-15. Money well spent to isolate your problem. Just don't forget to kill the electricity to it when you're done using it!

I keep one of those handy for pumping all kinds of fluids when the need arises.
 
#10 ·
take a length of fuel line, attach it to the line to the tank. have someone take the gas cap off and put a ear close to the filler hole. now do your best wolf imitation and huff and puff and blow into the line. you should have the person in back hear bubbles in the tank. if not, you have blockage or a cracked rubber line jim
 
#11 ·
Or your out of gas, bought a 71 Chevelle more door a couple years ago. I think someone siphoned his tank. owner put a new pump, intake and carb and never got it running. I towed it home, put gas in the tank and it fired right up. jim
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top