Perhaps you guys can figure this mess out. This system worked with the mallory 140 but when I installed the 250 it leaked like a sprinkler. So I ship it back to jegs and hook up the new one. The tech at mallory says it should work fine with the 250 the way I have it set up. It acts as if there is a major clog in the pump, when I first turned it on it was pretty quiet as soon as it primed the preessure builds in the pump and it pukes out the center of the pump where the pump meets the motor. Take a look at the pics, of the system maybe Im missing something. The pics are on page 2 if there not up yet it will be soon. Any sugggestions are appreciated, Im determined to make this work.

Http://community.webshots.com/user/67ragtp

Thanks Rich

Your returning to the tank via the #4309 return style regulator right?

My first suggestion is real basic...check that you have all the pump and regulator ports plumbed properly. On the regulator, the 4 ports around the outer diameter are the fuel inlet and carb port outlets. The bottom port is the return. The pump "should" have clearly labeled ports.

Now, if this is fine and your still having problems, I'd disconnect the pump outlet and plumb a line from the pump to a bucket. Turn the pump on free flow into the bucket to see if the pump spray out the body as you noticed previously. This test will tell if there's an issue with the feed/return lines or the regulator. If this test is fine, then your problem lies further forward.

Have you been able to ckeck for your fuel pressure at the carb/regulator while the pump is running/leaking/spraying? If so, was the pressure at a typical 7 or so lbs? I believe the line pressure of the Comp 250 is preset at 15 lbs of feed/line pressure.

If the free flow test is fine, I'd next disconned the feed & return lines and blow pressurized air through them. This is to see of there happens to be a flap of rubber blocking the flow path. Not real common, but can happen. If the lines both check out OK, then I's look at the regulator to see if it's flowing as it should and is returning fuel or blocking the flow.

It's tough to diagnose over the computer. i always recommend breaking a system down into basic components and eliminating issues one at a time...process of elimination...works with electical, fuel, tuning, etc.

10sec,

The regulator is the 4309, the thing that really confuses me is how the lines and fittings and regulator worked well with the 140. This was strictly a pump swap and no other changes all in the same location. Thanks for the ideas on testing the system. I did have around 9psi on the first 250 I installed, while it was leaking, I ran the adjusting screw on the reg. out a couple of turns to around 7 but it was oscillating a bit. The needle on the guage never became steady. The tech at mallory was convinced it was a bad shaft seal or it was tampered with. He said it was a good thing I turned it off right away since fuel could possible get to the motor of the fuel pump if the shaft seal goes :eek: . Its hard for me to believe I have got 2 bad pumps in a row.

Thanks Rich

Your pictures made this one easy. That fuel pump MUST have the port that is labeled 'BYPASS' ( which you have a block-off cap on) routed unrestricted directly back into the fuel tank.

Louie

Run your return line from the regulator into a 5 gal fuel jug at the front of the car and see if it still leaks.
You also you can try a free flow test by removeing the regulator and checking how much unrestricted fuel pressure you have.It should only be a few lbs.

Originally posted by LouieHammel:
Your pictures made this one easy. That fuel pump MUST have the port that is labeled 'BYPASS' ( which you have a block-off cap on) routed unrestricted directly back into the fuel tank.

Louie Sorry, but that is wrong. The bypass port on the pump gets plugged off when you use the #4309 return style regulator.

Excuse me, I made a big mistake. I forgot to mention that right in Mallory's own catalog it says that the 4309 regulator is only rated up to 200 gph and is only used on the 70, 110, and 140 pumps. You will need to use either the 4200 regulator or the 4300M.
I'm surprised that Mallory's tech person missed this Sometimes actually reading the instructions can help, especially if they are for the products you are getting paid to represent.

Sorry if I fried any brain cells out there, just tryin' ta be helpful.

Louie

When I bought my Comp 250, the 4309 was the recommended regulator. The small two port dead head regulator is what was used on the Comp 140 and smaller pumps.

I've been using a Comp 250 with the #4309 regulator for over 8 years of trouble free service.

Raising the pump volume increases the requirements of the return line. A -8 return line will work with a 140gph pump, but a 250gph pump will probably require a -10 return line.
Where is the regulator located?

First, yes you should use a larger regulator (such as the 4300) when using a 250 pump. The 4309 will have too much restriction and you may not be able to get the regulator to adjust down to 3 psi or less (which is how you tell if the regulator or return line is too restrictive).

Second, for the same reason, a 250 pump needs a -10 AN return line.

Finally, even though the regulator and the return line are too small, you still should not have a leak at the pump. Pull the electric motor off the pump and check the shaft seal where the motor shaft enters the aluminum gerotor housing. Is there a seal in there? If so, does it appear damaged? If the seal is missing or damaged, there was a serious error made during assembly at the factory.

RobbMc
Mallory Engineering Dept.