I have a relatively stock B20E with MSII (fuel only) replacing the D jet. I am running 2 squirts alternating in the injection control. With the stock Bosch injectors running at 28 psi I have a Required Fuel of 8.3 mSec. I have noticed that at idle my fuel pressure is fluctuating rapidly about +/- 2 psi which I attribute to the inability of the Aeromotive pressure regulator to control pressure at really low flow rates. The fuel pressure smoothens out at higher engine speeds and loadings.

It occurred to me that switching to 4 squirts alternating would level out the fuel flow at idle and perhaps reduce the fuel pressure variation; however, that would drop my Required Fuel down to 4.2 mSec which is below the recommended minimum of 6 mSec in the MegaManual.

I don't know whether the fuel pressure fluctuations are causing a problem; however, I was curious as to whether anybody has tried and had an improvement with the 4 squirts alternating arrangement on the B20E. 2 squirts alternating seems to be the more common arrangement.

What does the pressure do if you run the pump steadily but without the engine running at all?

Relatively steady at 28 psi. Very very slight fluctuation (less than 0.5 psi) as the fuel pressure regulator modulates flow on the return line to maintain 28 psi.

OK then when you start the engine at about what frequency does the pressure pulsate? Also is the regulator hard-mounted to the engine or isolated via rubber hoses like the original configuration? (I'm wondering about vibration.)

The needle is a blur. Each injector bank is opening approximately 15 times a second at 900 RPM so with alternate fire the fuel pressure pulsations are probably 30 hz.

The regulator is mounted on the firewall as per the early D jet installations so it is isolated from the engine.

You should use the later double ended sytle.

Do you have an oil filled fuel gauge?
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69 142S Overdrive + 69 164S Manual