Engine cutting out,,,Can't seem to figure it out....

[norms440]

Like they say two heads are better than one..Hopefully here there is a lot more here,,,Well heres my deal.Driving 68 over weekend was running great,,driving around 35mph all of a sudden it starts to die like its running out of gas.If i push in clutch and rev it it wants to die,,If i keep rolling with the clutch engaged and I am going fast enough I can bring it back to life..Until the next time it decides to do it again,,I replaced the tank with a brand new one,I have new 1/2 inch stainless from tank to pump,carter high volume pump (it has been on the car for 10 years),,new fuel filter,new filter in tank,brand new Holley street avenger 870 carb,,Its very aggravating..It also does it sometimes when I go to start it..I will crank it,it fires then dies no matter how much i pump the gas,then crank it same thing.Then I will get it started and will have to rev the heck out of it to make sure it wont die..Then were good till the next time it wants to be a pain,Its not ignition because I figure it would back fire..The only thing I possibly thought of is maybe the fuel filter in the tank is off and clogging it..but then it doesn't matter if tank is 1/4 or full...ANY IDEAS? I hate to drop $150.00 on a new pump and find out thats not it..THANKS IN ADVANCE FOR REPLIES....

[firefighter3931]

Have you checked the float levels ? Another thing to look at is the fuel pump pushrod...if it's worn down the symptoms you describe are often present. Start there first.....

Ron

[Chryco Psycho]

10 year old pump could be the problem as well , you could hook up a pressure guage to the feul line & see fi the pressure is dropping off

[1970440RT]

Don't count out ignition just yet, before getting a new pump I would test the coil and ECU.  I also had a cracked distributor cap that would manifest itself as you described.

[is_it_EVER_done?]

The next time it dies, let it, and coast to a stop in neutral. Pull the air cleaner and see if you are getting a good shot from the accelerator pump when you work the throttle by hand a few times. If not, you have isolated it to the fuel system, or if the pump shot is good, you have an electrical system problem.

My guess is a fuel problem. You say you have 1/2 inch fuel delivery line. Is it based on, and routed the same as the stock type float/pickup? Also, what fuel pump, and mounting location are you using? Did you ever have the problem before the fuel system upgrade?

The reason I ask, is that I have found that 1/2" fuel line when routed the same (suction type pickup) as the stock system can loose it's prime fairly easy. That's one of the reasons that race cars use bottom feed fuel pickups so that they have a gravity feed/prime.  This is one of the reasons that (very often) people that use external line Milodon oil systems have prime problems.

Often, the good ol' "If somes good, mores better, and too much is just right" approach that is frequently stated as the preferred method for anything, isn't.

[firefighter3931]

  Did you ever have the problem before the fuel system upgrade?

The reason I ask, is that I have found that 1/2" fuel line when routed the same (suction type pickup) as the stock system can loose it's prime fairly easy. That's one of the reasons that race cars use bottom feed fuel pickups so that they have a gravity feed/prime.  This is one of the reasons that (very often) people that use external line Milodon oil systems have prime problems.

Often, the good ol' "If somes good, mores better, and too much is just right" approach that is frequently stated as the preferred method for anything, isn't.

Those are good questions. Is this a new problem since the 1/2in line install ?

Is it ever done brings up a good point about the 1/2in line. It's possible that the pump can't pull enough volume through the larger diameter tubing so the result is a pressure drop at higher engine speeds. I wouldn't be surprised if that is the case in this instance. A 1/2 in line is way more volume than you'd ever need with that engine combo. A 3/8 line is plenty for a 600+ hp engine. 

Ron

[tecmopar]

Check the tank vent line. I had one blocked and it pulled so hard the tank started to collapse, just a thought. Next time it does it, open the gas cap, if you hear a rush of air that could be it. Some times its the simple things we over look.

[NYCMille]

Make sure you check the ignition. I had the same problem that plagued me for a year. I was running a Crane HI-6 box and coil and my symtoms are EXACTLY what you are describing. A friend recommened that I chance the box but I was reluctant due to the cost. Anyway, I bit the bullet - put in a MSD 6AL box with Blaster II coil and WALLA!!! problem solved. Prior to this I had replaced almost the entire fuel system, heat wrapped all the lines, but in spacers to prevent vapour lock, replaced the fuel tank and sending unit trying to solve the problem. It was the ignition all along... DOH!

EDIT: Just re-read your post - my car never backfired, so again, don't rule out the iginition.