Fuel pump pressure

[moparcleyon]

I have a 1963 Savoy 426 maxwedge and all of a sudden the fuel pressure went to 12 pounds. So I changed the pump with a used one I took off a running engine with less than 500 miles and the pressure went to 9.5 pounds. Engine floods out. What's going on..The fuel pumps should be around 6 to 7 pounds. It's a mechanical carter pump.. Why so much pressure? Cleyon

 

[Meep-Meep]

I agree that makes no sense. Go to the hardware store and get a gauge with about a 30 PSI max reading (to maintain accuracy) and check it again.

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The flooding is indicative of too much pressure but what about crap stuck in the needle and seat? Anyway, backing up your reading with another gauge will take that possibility of error out of the equation.

 

[70rr-brian]

Maybe your float level is too high? Maybe clogged filter?

 

[super-bee_ski]

yzfoot,
Couple of questions first:
1. How long have you owned this car/engine?
2. Is it a real Max Wedge engine?

Why do I ask?
Simply put, ALL Max Wedge engines "flooded out" Period!
Yes, it's true (as you may already know what I'm talking about)
The runners on a Max Wedge were (are) so long, these animals would take 20 minutes to "warm-up" (again, you already know that)
During cold days or high humidity, the engines were extremely difficult to get "warmed-up"and present a decent idle to be driveable.
Again, owning one, you know that.

Does not the Max Wedge fuel pump have more "flow and pressure capability?"
FROM: "maxwedge.com" :
Three valves provide extra pumping capacity. High spring load provides higher fuel
pressure
FROM: "maxwedge.com":
This engine is designed primarily for the elevated operating temperatures
generated by performance driving. That's why heating arrangements have been
removed from the intake manifold. During cold-weather operation, the resulting
tendency toward carburetor icing and delayed warm-up can be combatted by partially
covering the radiator, using a gasoline with anti-icing additives, and allowing
the car to stand for a few minutes with the engine

My advice, call the expert, Mr. Dale Reed, Baldwin Park, CA (He built my engine)
Dale Reed Professional Engine Builder specializing in high performance Mopars 5125 Lante St. Baldwin Park, California 91706 626-851-1353.

This is Mr. Dale Reed with my Max Wedge (440 build-up)
Call him.

 

[bigbear]

Just my two cents , but could the carter fuel pump that you took off the other engine be a carter performance pump ? That would account for the 9.5 pressure that you getting from it .

 

[super-bee_ski]

Another point is:
If a "High Performance" engine is NOT getting enough fuel, it will MIS-FIRE, all indications will be "Flooded"
But in reality, it is actually starving for fuel.

That is why, in my previous post I quoted from "maxwedge.com" stating:
"Three valves provide extra pumping capacity. High spring load provides higher fuel
pressure"
Qute from: "maxwedge.com"

So: Dose'nt this mean the Max Wedge fuel pump has:
1. Extra pumping capacity?
2. Higher fuel pressure?

 

[moparcleyon]

Both fuel pumps are 6 pound carter's. The car has ben running good for a long time. The first pump has been in the car for about 8 years. The 2nd pump was on a 383 that worked fine. Also I even changed carbs off another maxwedge engine that worked fine.. Changed plugs too. But now to much pressure.. Cleyon

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Super- bee ski
I know Dale Reed he has built several engines for me ,I will give him a call.. Thanks

 

[lewtot184]

those pumps are fairly easy to take apart and diagnose. the spring for diaphragm controls the pressure and has a seat it fits into in the upper section of the pump. maybe the spring isn't seating properly? you may have something goofy with the valves. they're simply spring loaded discs, maybe some trash in one is not controlling the fuel flow?

 

[super-bee_ski]

Both fuel pumps are 6 pound carter's. The car has ben running good for a long time. The first pump has been in the car for about 8 years. The 2nd pump was on a 383 that worked fine. Also I even changed carbs off another maxwedge engine that worked fine.. Changed plugs too. But now to much pressure.. Cleyon

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Super- bee ski
I know Dale Reed he has built several engines for me ,I will give him a call.. Thanks

Yeah,
He's a great individual...an a true mechanical wizard/expert with "Old Hemis & Max Wedge engines.

Interesting notes from maxwedge.com stating the fuel pumps on Maxies were higher output and higher pressure..you see that?

 

[moparcleyon]

Well I install another pump and it stayed at 6 lb's for 20 seconds then went to 9 lb's. Restarted the car and the pressure went to 11 lb's right away.. Used different pressure gauge same pressure. All carter pumps..Fresh fuel and new plugs..Cleyon