Originally Posted by GregBBRD

The squeal sound is the injectors spraying as the fuel pressure hits the fuel distributor and the injectors.
If the injectors spray without cranking, the engine will be flooded.
The next time you hear this sound, go disconnect the cold start valve (so no more fuel is added into the intake), apply full throttle, and see if the engine starts better.

The fuel accumulator keeps this from occurring, normally. (It's the "shock absorber" in the fuel system.)
Anything abnormal about the accumulator? Correct part number? Hooked up correctly?

Your warm-up regulator has the adjustment "pin" very deep into the regulator, as you suspected.
I'd get this pin back to the correct starting depth and then adjust the pin to get the proper fuel control pressures.
You get the control pressure low enough and this will also blow the injectors open when the engine is cold.

The system pressure is reduced by the control pressure. This is what the injectors "see".
So, if you have 5.8 bar of fuel pressure and the control pressure is 1.0 bar, the injectors "see" 4.8 bar of pressure. If you have 5.8 bar of fuel pressure and the control pressure is 2.0 bar, the injectors will "see" 3.8 bar of pressure.
Keep in mind that the fuel pressure at the injector is what makes them spray.
(The above is not exactly what occurs, but close enough, for this discussion.)

Originally Posted by GerritD

Hi Greg, currently I leave the cold start valve disconnected all the time.
I doubt a full throttle will help because a full throttle means the air plate will move downwards, pushing agains the piston inside the FD and thus opening the injectors, spraying too much fuel in the cilinders and thus flooding. You can pull the fuel pump relay and open the throttle wide open, to see if the engine is flooded.

As for the accumulator, bosch part number is 0438170026. The connection in the middle of the fuel accumulator is connected to a fuel line towards the engine. The outer connector on the accumulator is connected to the line coming from fuel pump. That sounds correct.


As for the pin on my WUR, according to the KJET workshop where I overhauled my WUR, the depth is not important since calibration is made on temperature conditions together with correct pressures.
Also when measuring the cold start pressure, it was about 1,1Bar (16Psi) at 18°C (64°F) which seems to be correct. I thought that I read that you had high cold pressures....my mistake.

And what about the AF rate set by the screw on my FD ? Currently I have set it with a CO meter pointing 1,8 % (should be in range 1,5 - 2.5).....

The only thing I can think of is that my coldstart valve sometimes leaks when presurized during start....I need to check that when I hear a squealing sound, there maybe is a leak on the coldstart injector. I doubt the leak will be on the 8 injectors since they are all new.

Originally Posted by GregBBRD

Originally Posted by GerritD

When I run the fuel pump manually (bridging) without pushing the sensor plate, I can hear the squeal noise for only 1 - 2 seconds. When doing this several times in sequence, there is no squeal noise anymore. So I doubt it is related to the injectors…
Could it be the kjet mixture plate that is linked with the piston in the FD? That’s why I wanted to know if this is AF ratio setting related

Originally Posted by GregBBRD

You asked for help....I'm trying to help you.
I'm not guessing at this...I'm telling you exactly what is happening.
The squeak is the sound the injectors make at very low pressure/volume.
When the fuel pressure is hitting the injectors for the first time in many hours, some/possibly all of the injectors are opening.
This is flooding the engine.....making it difficult to start.
Once the noise no longer occurs, with the fuel pump jumpered, you can very gently push down on the sensor plate to recreate the same noise.
(This will flood the engine further.)

The trick is going to be figuring out why this is occurring, not what is occurring.