With respect to your VP injectors and poor fitting seals. Measure the diameter of the plastic fitting on the end of the injector (the part that covers the pintle). The diameter on Bosch and exact fit replacements is approximately 9.2 mm. If your injectors 'tips' are 9.2 mm, then the original style seals should fit. Some of the aftermarket seals are poor fitting; however, even good correct fitting seals are a struggle to get the injector in place and the locking collar correctly locked. Spraying the seals with silicon spray can help with the installation. I prefer to coat the seals with dielectric Permatex dielectric grease which is actually a silicon grease. Unlike spray, it doesn't run off and gives a nice long working time. It still requires a fair amount of push to get the injector in place with a new seal.

If your injector tips are 9.2 mm in diameter, then Eric can probably supply you with the correct seals. Also, Rock Auto may still sell them, IPD probably sells them and Iroll probably sells them. If the injector tips are not 9.2 mm, then I don't know what VP has sold you for a replacement injector. In such case, you may be stuck with whatever seal they provided.

I failed to notice the comment in your first post that the engine briefly fires and then dies. If the engine briefly fires while cranking and then dies when you release the ignition key to the run position, then the D jet 'MAY' be failing to make the transition from starting on the cold start injector to running on the main injectors. If this is the case, then there are a number of possible problems.

- Problems with the manifold air pressure sensor (MAP) have already been discussed. If you have done the basic tests and it has passed then that is all you can do for now. If you eliminate all the other causes you may have to come back to the MAP.

- Problems with the set of two contacts in the base of the distributor. As described in the D jet trouble shooting manual you need to insure that both contacts are opening and closing as the engine turns. When the contacts are closed make sure the resistance is low (probably 1 ohm or less after adjusting for your measurement leads). High resistance when closed can lead to flaky operation. Both sets of contacts must operate. The two contacts form the input to an electronic circuit called a toggle that switches back and forth between the two injector banks and triggers the timing for the injector duration. If one of the contacts doesn't work, the circuit hangs up on one side and nothing happens because the controller fails to get an RPM signal.

- problems with the auxiliary air regulator and the throttle position switch. You need to insure that the aux air regulator is opening and closing. If the aux air regulator does not open on a cold engine the engine will not get enough air to sustain operation. It will also make cold starts difficult. Follow the procedure in the D jet trouble shooting manual for testing the throttle switch and setting the throttle switch. Correct operation and setting of the throttle switch is critical to D jet operation.

I no longer use the D jet controller on my B20E; but, I recall that there is a test that you can perform on the D jet using the throttle switch. You turn the ignition key to the run position and then turn the throttle (and throttle switch) from the closed position to the full open position. You should hear the injectors click open and closed something like 11 or 12 times. I think the test is described in the manual and if not current D jet owners may be able to provide the specifics. If the injectors are hard to hear, you can purchase injector test lights to confirm that the injectors are getting the on-off signals.

Note that the presence of 12 volts at the injectors is not an indication that things are working. When the key is in the run position, there should always be 12 volts at the injector terminals. The controller turns the injector on by applying a ground to the unpowered side of the injector (ground switched system). The preceding test using the throttle switch (and lights if required) confirms that the wiring is good and the controller is doing its switching action.

When checking the electrical connections on the D jet, it is usually not the plug that fails. Rather, check the wiring for about 6 - 8" back from the plug. This may require cutting back and then repair of the jacket. The insulation becomes brittle with age and can flake off leading to internal shorting. This is particularly prevalent on the injector plugs and coolant temperature sensor plug which get a lot of heat exposure. The wiring to the throttle position switch is also a problem because one side of the wire is fixed on the fender and the other is attached to the engine. B20 engines vibrate and move a lot. This can lead to a lot of flexing and fractures of the wire where it plugs into the switch.