Fuel Injector Pump in compression?

Hi to all,
In an effort to fix a leak from my injector pump I am at the stage where I am about to gradually back-off the screws on the distributor section of my BOSCH VE injector pump in an effort to replace the o-ring. I understand that the pump should be in compression to do this correctly.
This can be done by turning the engine but how though can I tell when the pump is in compression without viewing the internal spring? I do not wish to remove the top part of the pump to reveal the internals.
Would the pump be in compression when I can place timing pin in the slot?

Cheers

Do not forget the pump injects 4 times per revolution, so and I am assuming here it will be under load 4 times per complete revolution

Will be interested to hear how you get on,

Personally doing it in situ is not something I would do, as taking it off the engine is not that difficult.


Cheers

It is a lot easier to turn over on the bench, rather then in the car with the timing belt on.

trust me just been doing my front seal on the pump and re-timing it with the DTI gauge in the vehicle is a bugger wish i had got it right on the bench..

All of your points are valid.

I understand. The problem is that just 4 months ago I removed the entire front section and timing case to replace the gasket that sits between the rear of the timing case and the engine block. That involved removing the sump as well. I regret not removing the pump then and having it reconditioned.
I pretty much have the pump in place but cleaned and stripped and I am ready to replace the o ring at the distributor section.
To be honest If I had a pump removal tool I will have already removed the pump but I don't have one which means I will have to do a complete disassembly of the front section again... radiator, ac condensor, coolant hoses etc.

I "practiced" backing off the distributor section on another pump I had access to on a bench to reveal the o-ring, so I have a feel of how to perform the task.

I am just concerned of the small spacer on the plunger assembly. If the distributor section is backed off too much that spacer can potentially drop out. I believe that is why the distributor section should not be backed off unless the pump is in a compression stroke to exert the necessary pressure to keep all the bits in place. Hence my original question that I posted.

After doing some research it seems that when the pump is at TDC the pump is in compression or at the point of highest lift.



That was what I was trying to determine all along I guess.




Cheers[/QUOTE]

Good Luck
have had my pump on and off the vehicle about three times in the last week.

hopefully on for good now..