I am trying to decrease the fuel pressure in my TA. It has the stock TPI fuel pump in the tank. I have that hooked up to a mallory afpr.

I was playing around with the pressure settings, and from about 2 - 4 psi the car is good. I try and adjust upwards to get more of 6-7 psi and it fluctuates rapidly. At this psi I can hear my fuel pump making funny noises, and the pressure goes up and down incredibaly rapidly. If its at about 6, it will fly back and forth between 5 and 7. I have the end of the fuel line plugged with my finger and its a very noticable rapid surging. I have the lines hooked up correctly (hardline to mallory afpr are rubber). Neither of the fuel lines are kinked. the return line is bent in a very slight S, but it doesn't look like its putting any pinch on the line. I checked my fuel tank guage and it is low, but a good 20-30 miles away from causing the car to cut out.

Does the Mallory AFPR vaccum port need to be plugged or left open?

Does anyone have any suggestions on how to steady my fuel pressure?

 

Run 2 regulators. Use the hardcore mallory regulator to get down to maybe 10 psi, then use an el cheap o regulator to go from your (fluctauting) 10 down to 6.

 

I did more testing. If I set the reg at 4 psi it works fine. I can adjust it up to 5 to 5 1/2 before it starts bouncing out, but if I shut the pump off and restart it, it will be bouncing. Can I run the carb with only 4 psi? Also, when It starts fluctuating, I can hear a large clunk.... clunk... that is even, but I cannot tell where it is coming from.

Unfortunately the only reg available locally is a spectre 1-5 psi, but I suppose that between the two regs I can get it into the 6's.

 

X5,

4 PSIG should be fine. As long as you're not in Suprior on some of those 45° inclines, the pump should be able to get the fuel to the carburetor. 4 pounds is about the same as 10' of head pressure, so unless the carb is 10' above the regulator, your pressure should be adequate. As long as the pump can maintain flow VOLUME you should be fine.

------------------
Later,
Vader
------------------
"Let the bodies hit the floor!"
Adobe Acrobat Reader

 

Well, the 4lbs is at the REG, which I assume is close to the carb and not the tank/pump so he's good. The FP at the pump will be higher, making up for head loss.


EDIT: more importantly, you might want to invetigate that noise as so you do not get stranded!

[This message has been edited by FastBroker (edited June 04, 2001).]

 

I did attempt the two pressure regulator thing, and I got the same result. I can get the pressure (the guage is on the carb fuel rail) to about 3.8-9 and when I turn on the ignition the car chunk.. chunks.. a few times before it smooths out and runs smoothly.

I think the mallory regulator is junk, and perhaps I should mount up an electric fuel pump. Where should I mount it?

Thanks all!