No fuel

[jdiesel33]

After a couple of years of anticipation, finally got the rebuilt motor cranked up this weekend. Sounded loud and bad ass with the big carb and Doug's Headers. Started right up no problem. Issue is, once the gas in the carb ran out, it would die, No fuel getting from the tank up to the pump. What all could cause this or what should be the first thing we should look at? We tried blowing air thru the line that goes to the fuel pumpbut nothing happened. Seems to be a blockage somewhere. I'm afraid we will have to drop the tank and investigate, which isnt a huge undertaking but still a pain. Wanted to check with you guys first.

[bobs66440]

Is it a mechanical or electric pump? Is the pump working? If you don't have a blockage in the line and there's no fuel being pulled, then the pump must be bad. If the pump is working, make sure the fuel filter isn't clogged.

[jdiesel33]

Mechanical pump. There was a good vacuum on the hose to the pump when we took it off. i think the pump is good. the fuel isnt even making it that far. I have a brand new vapor separator, no actual fuel filter. Is is possible that the vapor separator is the problem? Everything single component of the fuel system is new - tank, pick up, float, vapor sep, lines, fuel pump, etc..

[BananaDan]

I put new fuel lines, sender, vapor seperator etc in two years ago.  At Carlisle this past summer, on the way home, she wouldn't stay running.  Chris6T9 was with me thankfully and diagnosed that my fuel pump push rod was worn and wasn't fully engaging the pump.  The engine was freshly rebuilt also but if you can't blow air through the line it sounds like you have a bigger issue.  Is it possible your new line got kinked somehow on installation, or your sending unit is bad?

[jdiesel33]

I would say the sending unit is probably the most likely guess at this point but I will certainly check to make sure the line isnt kinked. Would it be to safe to say it isnt the fuel pump if the hose going to it had a good strong vacuum on it when pulled off? Im not a mechanic and couldnt even play one on TV, but learning as fast as I can. 

[b5blue]

  With the feed to the pump line off you should be able to siphon fuel freely with no problem. A small amount of suction should be having fuel flowing nicely. I use a suction gun from Harbor Freight that's about the size of a grease guns body. Be sure you have the feed and not return line for feeding the pump. To test the pump take about a coffee can size worth of fuel fed to the pump through a short hose and do a cranking test, it should start pumping fuel in short order.   

[jdiesel33]

Tried sucking some fuel thru that line, but absolutely nothing. That is what leads is to believe it must be an issue before it gets to the pump.

[b5blue]

How much is in the tank?   

[bobs66440]

Is the gas cap vented?

[Fred]

Without actually being able to see it for myself I would hazzard a guess that it's the fuel pump push rod or esle the pump itself. 

[FLG]

Remove feed line from pump, put it in a bottle/gas can whatever (just make sure you dont spill it and cause a bigger problem)

Put some fuel in the carb and start her up, your going to need to get it running for a bit to start to siphon fuel from the container, but not very long. If it works than your good to go, if it dosnt than you either have a blockage from the pump to the carb, bad pump, or worn down pushrod.

Assuming the test worked and car was running you either have a blockage from sender to the pump OR your simply not giving it enough time. Remove the line at the sender and at the pump, see if you can blow air through, if you can than see if you can blow air through the sender (i would advise using VERY low air pressure as you dont want to blow the sock of the sender) if thats all clear than and it passed the previous test, than you simply need to keep it running for a bit longer...it takes a bit for the fuel to be siphoned from the tank to the carb.

[jdiesel33]

Is the gas cap vented?

Hmmm...well since I didnt have the stock cap with me at the time, I used one of the twist on/off caps that were originally on my new valve covers and twisted it on there. Would that make a difference?

[firefighter3931]

If the tank is not properly vented there will be vapor pressure. Try removing the cap temporarily and run the car. Do this outside so that the vapors don't accumulate....and report back 


Ron

[Cooter]

Is the gas cap vented?

Hmmm...well since I didnt have the stock cap with me at the time, I used one of the twist on/off caps that were originally on my new valve covers and twisted it on there. Would that make a difference?

Sounds like your problem, or at least one of them. Never install a cap that even though fits, isn't a vented fuel cap. Good way to dent the tank, ruin the fuel pump, etc.

[b5blue]

Check the fill tube vent/overfill drain line. It vents into the frame rail. 

[Fred]

The cap doesn't have to be vented as there is a fill tube vent pipe.