Going Crazy with Fuel Pump Issues!

[70 RT FC7 CVT]

Hi Guys,

I've been going crazy for the last two days trying to diagnose my fuel pump woes. I finally got the 383 detailed and installed into my '70 Challenger and got it fired up. I had to prime it with gas through the carb to keep it running, hoping to work the fuel from the tank through the pump and up into the carb. After awhile, I was convinced the pump was bad.

I went and got a new pump today and tried to get it installed. I greased up the pushrod to keep it up while I got the pump installed. It was really tough to get the pump installed, it didn't want to go in straight or it felt like it was going in too high or too low. The pushrod stayed up the entire time and didn't drop back down. I finally got it in by getting it close and slightly twisting the pump slightly to get the bolts lined up.

I then put a fuel hose from the inlet into a cup of fresh gas and cranked it over...........nothing, no fuel was pumping from the cup of gas through the pump. I'm at the point of pulling out my hair trying to figure out what could be the issue. I doubt the new pump is bad, the pushrod doesn't seem to be too worn but I haven't taken it out to make sure. 

Has anyone ran into this before or know any tricks to diagnosing it? The old fuel pump was a lot easier to put on when the motor was out of the car, definitely a little frustrating trying to get the new pump on with the motor back in!

Thanks!

[Chryco Psycho]

my bet is the pushrod , the ends are smaller diameter & equal in length , I bet anything the tip is worn off one end

[70 RT FC7 CVT]

Thanks Chryco, do you happen to know the right length and the best place to order a new one from?

Best I can tell from reading through old topics, the Mopar Performance ones aren't highly recommended.

[Chryco Psycho]

Not sure who has them , I have ordered from Mancini & theirs are Mopar

[shadango]

Hi Guys,

I've been going crazy for the last two days trying to diagnose my fuel pump woes. I finally got the 383 detailed and installed into my '70 Challenger and got it fired up. I had to prime it with gas through the carb to keep it running, hoping to work the fuel from the tank through the pump and up into the carb. After awhile, I was convinced the pump was bad.

I went and got a new pump today and tried to get it installed. I greased up the pushrod to keep it up while I got the pump installed. It was really tough to get the pump installed, it didn't want to go in straight or it felt like it was going in too high or too low. The pushrod stayed up the entire time and didn't drop back down. I finally got it in by getting it close and slightly twisting the pump slightly to get the bolts lined up.

I then put a fuel hose from the inlet into a cup of fresh gas and cranked it over...........nothing, no fuel was pumping from the cup of gas through the pump. I'm at the point of pulling out my hair trying to figure out what could be the issue. I doubt the new pump is bad, the pushrod doesn't seem to be too worn but I haven't taken it out to make sure. 

Has anyone ran into this before or know any tricks to diagnosing it? The old fuel pump was a lot easier to put on when the motor was out of the car, definitely a little frustrating trying to get the new pump on with the motor back in!

Thanks!

If that doesnt end up being the issue, have you looked at the more obvious issues?

Too low fuel level in the tank, clogged pickup, clogged fuel line, etc?  I am sure you have checked these but...never hurts to double check?

[73EStroker]

Try the old trick of blowing back to the tank with some compressed air from the line that comes from the tank to the pump. Be careful though as you don't want full pressure as you could blow the line or connections. When I used to do this I would use the air blow gun and hold it about an inch from the line and let it have the air from there. What this will do is verify if the line is plugged. If it is then you have to clean everything out. Typically if you are running original tanks and lines in these cars you are going to end up with trouble due to their age. I replaced everything (tanks, lines etc) so never had issues. Rust is the biggest problem so make sure you run a pre filter before the pump and carry a spare for those roadside changes.

[72cudamaan]

I agree with Chryco as the OP said he still didn't get fuel from a cup of gas thus eliminating
the rest of the fuel system. Pull the pump rod and check the length.