Car falling flat after 2nd gear - carb trouble?

[MyMopar]

Well I'll be damned if I don't fix on ething another pops up.  This one is a bit strange.

I get in the car, start it up.  I can take off hard on the throttle, shift from 1-2, but halfway through 2nd gear (3400RPM or so) the car falls flat on its nose as if it just ran out of gas.  If I get off the pedal and coast for a bit, I'll have throttle back, but the same thing will happen.  I really can't get on it for long without it stalling out on me.

So I'm thinking the problem lies within fuel delivery.  I rewired the fuel pump and checked the connections.  Still the same problem. 

I did check the front float level and fuel trickeled out the front bowl, but didn't check the rear.  If the rear float is low, then I can understand the problem, BUT if the rear float level is right on, what else should I check for?

Carb is a Holley 750 vac. secondary, 440 auto. 

The iginition shouldn't have anything to do with this problem, new coil and new MSD 6AL, spark timing is 16* idle 36* total and it is rock steady.

[Chryco Psycho]

weak pump or plugged sock in the tank or restricted fuel line would be where I would be looking

[MyMopar]

Brand new sending unit (3/8 line) and sock, I had the tank drained and cleaned.  New 3/8 fuel lines replacing the 5/16th lines too, checked and no leaks anywhere.  Brand new Holley red pump and the psi is set by regulator reading 6 psi now.  I figured their might be a restriction somewhere, perhaps the filter on the carb itself is clogged up or crap from the old tank is playing tricks with the needle and float, I'll have to pull them and see. 

[Chryco Psycho]

I assume you cannot see the pressure guage from in the car , having had a lot of problems with Holley fuel pumps that would be my guess , the vanes stick in the pump & it stops moving fuel , Mallory Gearotor pump would be my choice for electric pumps if you can return the Holley

[jeryst]

What happens if you floor it and wind it out while in 1st gear?

[MyMopar]

What happens if you floor it and wind it out while in 1st gear?

Well I don't know, I wind out first gear and when I hit second it starts to fall flat after a few seconds (3400rpm), so I know the fuel isn't really flowing anymore.  I figure if I stayed in first screaming down the road, it would do the same thing in a matter of seconds.

I'll check on the pump, I've never had a problem with the Holley's, but then again maybe I had and never realized it.

Oh and no I can't see the fuel pressure gauage when driving, but I'm thinking remote camera and seeing what that says, if it drops off, I know it is the pump.

[jeryst]

But you should easily be going past 3400rpm in first. Does it stumble at all then?

[tactransman]

Mallory Gearotor pump would be my choice for electric pumps if you can return the Holley

Quieter too!

[ntstlgl1970]

You need to see what the fuel pressure is doing, connect a fuel pressure gauge you can read while driving. Without knowing what the pressure is doing, you are just guessing. Another thing you can do is tee a vacuum gauge into the supply side of the pump, the gauge should never go above 5 in.hg. or so with the engine running. If the pressure falls off and the vacuum climbs, there is a restriction in the supply side of the fuel system - this isn't common, but it can happen.

[MyMopar]

But you should easily be going past 3400rpm in first. Does it stumble at all then?

No it doesn't. I start off in first and get on it, shift around 5700 the ninto second and I literally fall forward in my seat after a few seconds being in second gear.

I will rig something up so I can see the fuel pressure while driving, I'm also going to check the fuel level in the bowls, the front is ok, but I didn't check the rear.

[MEK-Dangerfield]

Yes, this could be a fuel pressure related problem. I installed a fuel pressure gauge not only under the hood, but I have an electrical one installed in my dash due to the fuel related troubles I have had(Loooong stories).

Since you have a vacuum operated carb, I wonder in you have played with the spring that opens up the secondaries? Maybe they open too fast, or too slow?  I had a similar problem in my double pumper where it was fine in first, but a slight stumble when it shifted into second if I was driving it hard. I solved that problem by going to a bigger accelerator pump squirter. Just another thought here.

  Mike

[MyMopar]

I solved that problem by going to a bigger accelerator pump squirter. Just another thought here.

  Mike

I do have an of idle stumble that will require some tuning of the accelerator pump like you mentioned.  I'll have to look into that electrical FP gauage as the ones I see are all mechanical.  I plan on using some fittings and hose to route the gauage where it can be seen just to check it, but I do have a small remote cam that I thing I'll try first as it will be safer than me rigging something up with fuel lines and such. 
I also installed a vac. sec. quick change kit, I am running a purple spring in there and from the stock spring to the purple, nothing different happens.  hryco is right, the problems lies somewhere in the fuel delivery, this week-end I'll have it figured out (hopefully).

[MyMopar]

Ok so this is what I did.  I replaced the 750 carb with a Holley 870 vac. sec.  2 things brought this on, first the new motor has more compression and I always thought the 750 was a bit little for the 440.

I installed a fuel pressure gauge and oil pressure gauge.

I started it up briefly today just to check on the oil and fuel pressure.  Oil pressure is 75 psi and fuel pressure is 5psi.  All seems good for now, I'll take it out for a drive tomorrow once the dash is back together from tracing wires. 

I should be able to isolate the problem better now.  Liek I mentioned before the fuel pump runs off a switch that is controlled by the oil pressure, if it goes too low, then the power is cut off.  Now I'll know if the switch is bad or if the oil pressure is dropping as the rpm climbs.

[nivvy]

Quieter too!

the heck with that! the more obnoxious the better.....i love my noisy gear drives as well....lol

[MyMopar]

Ok just got back from a little cruise.  Had a cop stop me and ask about the car, then he said I won't even joke about having a go, I'll lose, I was thinking that's right 
In any case at idle the fuel is 5 psi, as I take off down the road, the fuel pressure drops to 1.5 psi and holds steady around 1.5-2 psi until I idle for 15 seconds or so then it is back to 5 psi, but will drop to 2 psi if I start cruising again..
So now I know it isn't getting enough fuel because of pressure, so this is a good thing.  I'm going to take a better look at the fuel regulator.  The Holley site says when running the Holley Red pump a regulator isn't neccessary, they claim it is preset at 7 psi.  In any case, I am going to monkey around with the regulator for a bit tomorrow and see what I can do.  Perhaps the regulator is bad and I'll by pass it for a test, I'll find out tomorrow.
The new carb is already making a difference with idle though and I adjusted the timing for 14* initial and 34* total.  With iron heads and 10.2:1 compression I can't go too crazy until I get some high quality fuel or that octane booster that Mike talked about once.