K-Jetronic Diaphragm / Rebuild Kit Failure.

I have had zero issues with components rebuilt by 2 of the aftermarket resources. With Bosch rebuilt components I had a 100% failure rate.
We are better off without them.

 

This is service called Bosch Classic available in Germany and France since 2017. They had a showroom at retromobile 2019 with the R5 turbo.

https://www.bosch.fr/actualites-et-stories/retromobile-2019/

As far as k-jet ease of maintenance, I find it much more easier to dial than the 6 carbs of my brother's 365... If you know how to replace the gaskets on a Weber, the k-jet distributor is a piece of cake.

 

Except for the occasional fuel filter change there is nearly zero maintenance required. Repairs are in my opinion simple. It is a very simple system. It does have its faults. By modern standards it is not conducive to a high level of performance but speaking from the perspective of someone who was in the repair industry when it came into use we were really happy to have it. It enabled a level of performance and driveability we had not had in years. The fastest cars built all had it.

Has technology passed it by? Yes. But technology has passed everything from the 70's by.

 

This is not really a valid test (as it just applies a very high control pressure that never normally occurs) -- what you need is the WUR to apply the correct control pressure when warm and the correct control pressure when cold. Even if the WUR is working correctly (as verified by measuring the cold and warm control pressures), you can still have other problems in the fuel distributor -- that's why the most meaningful functional test is to measure the fuel flow rate at each injector for idle, mid, and high RPM positions of the airflow metering plate (i.e., also known as the "Dixie Cup" volume delivered per given time test). You may get to this point -- a picture of how I've done it on my TR using (plastic) graduated cylinders with the injectors in place:

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Some pics of how another FChatter did it on his 400i using small jars without the injectors:
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I once converted a 400i to electronic fuel injection using mega squirt. Worked like a charm.


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At what position of the airflow metering plate? At idle? I'm guessing that the volume of fuel you have there in each bottle is about 250 mL so, unless you went for a very long time at the idle position, you were at a very large fuel flow rate -- and, at large flow rates, they tend to be more equal even if the idle calibration setting is off. The idle fuel flow rate is about 6~7 mL/min so setting the airflow metering plate to a position where each bottle gets about 20 mL in 3 minutes is more representative of idle operation. (You may need to transfer the fuel from each bottle into some other more rigid/accurate measuring device to compare them as 20 mL isn't much.)

How did you initially set the adjustment screws acting on the springs of the ceramic plates to match each port at the idle fuel flow rate?

 

That won't help you diagnose an idle issue.

Never heard of that -- do you have a reference for it? AFAIK, they are adjustment screws meant to be adjusted to give equal idle flow rates.

 

Just a small amount -- like the top surface of the airflow metering plate being ~1mm down from where the reverse "funnel" starts. However, just do this as a starting guess -- once you run a test, and have the average amount of fuel that each injector is delivering in 3 minutes, adjust the position of the airflow metering plate up or down, as required, to get the average amount that each injector is delivering in 3 minute to be 20 mL. I just use a fixed spacer between the bolt head on top of the airflow metering plate and the rubber up stop to hold the airflow metering plate in a fixed position and then change the thickness of the spacer as required.

If you do the idle test, and the amounts of fuel delivered are in spec (all within about +/- 5% of the average amount delivered) = you'd have to keep looking elsewhere for a bad idle issue.

 

Lower flow rate consistency is going to be more important to overall running than having them perfect wide open.

Find something that can hold the plate in exactly the same position through the test and adjustment.

 

A 3mm drill bit is what I use. Just have to insert it between the bowl and the disk. Can be secured with some tape if need be but the control pressure holds it pretty well.

That's what is suggested in order to setup Weber DIR carbs.

 

My mistake -- didn't realize that you have updraft (and not downdraft) airflow metering units, but the situation is about the same (a small deflection from the cylindrical portion into the tapered funnel portion = idle).