QuestionQUESTION: Hello Howard,
Can you recommend a make/model of a fuel pressure regulator suitable for my 1980 MGB? I thought maybe from your experience you may have some preferred makes that you could recommend?
Thanks.
Wayne
ANSWER: Hi Wayne,
You don't need a fuel pressure regulator if you get the correct fuel pump. (A pump that produces from 1.5 PSI to a max of 3 PSI) You only need a pressure regulator when you purchase the wrong pump.
Howard
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QUESTION: The car had one installed when I bought it. It is a PRO FUEL chrome with adjustments from 0.5 to 5.5. The regulator leaks and I was going to replace it with a new one.
The fuel pump is an SU - I guess it is original. I can't read the label. It has a Weber 45 DCOE carburetor.
It sounds like you think I could eliminate the regulator?
ANSWER: Hi Wayne,
The SU pump normally pumps 1.5 to 3 PSI unless someone modified it. It operates by an electromagnet that retracts the diaphragm that draws fuel from the tank and that also makes a set of contact points at the other end (with the plastic cover) flip over and disconnect the electromagnet. A spring then pushes the diaphragm and fuel toward the carburetor that was drawn in by the electromagnet action.
That spring determines the fuel pressure. Even though the adjustment of the contact points will change the pressure a little, it will not change it enough to need a regulator. The only way to change the pressure very much is to change the tension on the spring.
In your case it is easy to test with a standard low pressure gauge. (many vacuum gauges have a low pressure fuel gauge reading included)
SU quotes one pint of fuel in 30 seconds delivery. In a practical application, I found that I could diagnosis a fuel pump by just installing a "T" in the fuel line close to the carburetor/s and activate the pump and if I seen from 1.5 PSI to 3 PSI it was usually ok. However that only shows pressure not volume. Rather then pump fuel into a container I chose to make a actual test by using a long hose on the "T" for my gauge and running the gauge out from under the hood and placing the gauge facing inward under a wiper blade so I could monitor the reading while driving and I would take it out on the road and apply full throttle in high gear for several seconds (max fuel usage)and if I seen 1.5 to 3 PSI I know 100% sure it is not a fuel delivery problem.
Many cars of different brands that used carburetors were brought in with flooding problems and many times I found an aftermarket pump that produced from 5 PSI to 7 PSI and they did not have a regulator installed. At that pressure many float needles are forced open and thus flooding of the carburetor is the result.
The DCOE Weber is a good replacement of the single Stromberg on the late model MGs. Weber carburetors never came on MGs.
If it were mine, I would get a low pressure gauge and "T" fitting and a long hose (WITH CLAMPS ON EVERY JOINT) and run the test I always did, which is a "Real-Time" test with no regulator and see what pressure I have at full throttle under load. I bet the gauge, "T" and hose cost less then a new regulator.
I always preferred "End Result Real time testing" over any other form of testing.
let me know how you make out with it.
Howard
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QUESTION: Howard,
I got a low pressure gauge and "T" and installed it. I couldn't find a fitting locally to let me hook a hose and run it to under the wiper to see the pressure while driving but I ordered one and it's on its way so I can do that test when I get the fitting. In the meantime I hooked the gauge up under the hood and after turning the ignition on and letting the fuel pump run until it stopped I got reading around 3 psi. After starting the engine the reading stayed around 3 with a little fluctuation.
However, I have a lot of smoke out the exhaust and under the hood. Under the hood it looks like it's coming from down around the header but I'm not sure. But the exhaust smoke is white and heavy. I just replaced the head gasket - this was the first I started it since doing that. It smoked before replacing the head gasket, but not this bad.
What do you suggest I do?
AnswerIt is unlikely a fuel supply problem. As for smoke, you need to look to see where it is coming from. Are you getting any smoke out the tail pipe? If you are using the original iron exhaust header, you need to examine it carefully as they were noted for cracking.
Why did you put a head gasket on? What tests did you run to determine it needed a head gasket?
What was the original problem?
Howard
