After three intank fuel pumps and one new main fuel pump, I still have Main Fuel pump noise. I've check pre fuel pump pressure and it is ok. I don't think the 1983 240 Turbo has a FPR. What else could be wrong? I've also look at FAQ.

I would very much like to fix this problem before resorting to modifying a later model 740 prepump.
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EGIII "1983 244 Turbo"

Did you replace the accumulator? The accumulator sits right next to the main fuel pump. Also inspect all hoses coming from the transfer pump to the main fuel pump for air leaks.

WilliamR.
84, 240ti

I've had 30 years of noisy fuel pumps and not once have I had a main fuel pump failure. Learned my lesson in the '76 when I changed a noisy fuel pump and was out $100 with absolutely nothing accomplished.
The B21FT does have a control pressure regulator under the intake manifold.

It does but it does not have the same function as a pressure regulator on LH. The control pressure regulator on the turbo regulates the resistance of the plunger in the air fuel control unit, not the fuel pressure.
How loud is your pump? Are you sure its not normal. Even good ones are not exactly quiet.

I have the same problem, the same model (83 240 turbo), and the noise starts when I change the intank pump, and I have to disconnect the oxygen sensor because I have to much rich mixure. And when my car stop, the pump still work. Before I dont have this poblem. Did you find an answer?

Edwin
240 Turbo '83