Ok, I have a installed a completely new fuel system. Fuel cell, Electric pump, regulator, 750 double pumper, all with stainless steel line. I have it set at 7psi fuel pressure. It was running fine for a day or so, then out of the blue - driving down the street -it died and would not start. After messing around with the carb settings, I could get it started enough to get it home (car died about 4 times on the way home-would not idle). I have narrowed it down to the fuel system, because when I crank it over, then release the key a cloud of smoke and gas spits out - even got a geiser of fuel to shoot up a few times!

Well after alot of trial and error, I could get the car started after taking the fuse out of the elec. fuel pump and after it is running I can get the car to keep running by reinstalling the fuse and turn down the fuel pressure to like 2 psi, or even 0 on the guage.

But it will not start with the elec. fuel pump hooked up at start.
Help, I do not know how to fix this!

Sounds like you might have gotten some crap in the needles & seats ;)
Try cleaning them out before doing anything else.

I'll bet there is some junk in the needle and seat, flooding the bowls. Pull out the N/S assembly and give it a good cleaning. This is not uncommon after working on the fuel lines.

Ok, I pulled the bowls and the metering blocks, and cleaned them out, there was a little junk in there. I made sure the floats were correct and the idle screws set to spec. I am still getting the same problem. :mad:
I let the fuel pressure build up (6psi), then cranked it over, but it still would not start. I removed the fuse for the fuel pump, then it starts right up and runs (until the fuel is emptied from the line). While it is running I can put the fuse back in the pump to keep the car running, but it is clearly too rich as there is excess smoke coming out the exhuast.
I dont know what else to do, seriously thinking about putting a manual fuel pump on and forgetting about the electic...any suggestions??

check the float level, fuel should be at the bottom of sight plug,if you have another fuel pressure guage try it the one you have maybe giving you a false reading and you may have to much fuel pressure.It shouldn't matter if you are useing a electric fuel pump or mechanical as long as fuel pressure isn't to high I wouldn't go over 7 1/2.

Ahh ahaha I figured it out! graemlins/thumbsup.gif
This is very stupid but what happened was that I wired the MSD and the Fuel Pump together at a 12 volt switched sorce. This was causing the MSD not to fire when the fuel pump was on.
This is why it was able to start when I removed the fuse for the fuel pump-because then the MSD was getting the full 12 volts. graemlins/boring.gif
Would the continuous cranking without starting cause the fuel to spout up like it did though?
I did clean the carb out (there was debris), so now it seems to start right up and run fine. Crazy stuff!...I just hope it keeps running fine, as I have only tested this a few start ups...
Thanks for the input.

I'm a litle confused about why they can't be wired off the same source. It should be just the same as a junction block. The only thing I could see is one device pulling too much current but this should blow a fuse. I run a Mallory setup and am not familiar with MSD requirements. Does your electric fuel pump use a relay to pull voltage and your switched source was only used to feed a relay? I don't see where this would cause a problem. Or did you feed your switched source straight to your fuel pump?

Yes, the fused fuel pump was wired to the MSD line which was connected to a switched 12 volt. I am positive this was it, because it starts and runs like a champ now.

Im sure the fuel pump was just drawing too much away from the MSD, so it didnt have enought to fire up.

...although after starting, I could re-attach the fuel pump and it would run...

either way, its all good now! smile.gif