Focus 1.6 TDCI question

[redtwin]

Recently had an injector seal replaced (2 injector feed and spill pipes undone) and after fitting we could not get the car to run. It did for a couple seconds, but spluttered and stopped. After many attempts to start it on the key, the mechanic (non-specialist, back street type) I was helping said "We will have to drag it".

I was really puzzled, but went along with what he was suggesting. We hooked up the car to the back of his, put the Focus in 3rd gear, switched on ignition and he proceeded to drag it across the yard. Sure enough, the car stumbled to life and has been fine ever since.

What did "dragging" it do, that the starter couldn't?. I assume there was a fuel supply issue most likely caused by removing the injector pipes, but why would dragging the car in gear resolve that?. I can't imagine there is a fuel pump drive off the gearbox (or is there) and 3rd gear at approx 5 MPH wouldn't have spun the engine any faster than the starter motor so why did it work?.

Mechanic couldn't offer a reasonable explanation beyond, "it just does". Can anyone better that?.

[shoehorn]

Cranking on a starter is a lot slower than a tow or push start(chances are you would have been going more than 5 mph as well)you will therefore turn the engine considerably faster than starter cranking,which will turn the pump quicker.
These modern high pressure pumps seem to have poor lifting properties made worse still by the presence of air in them, basically higher pump speed=more chance of shifting air.

There is nothing more annoying on some modern cars when you are trying to crank one over to bleed them only for the ecu to keep cutting the cranking signal every few seconds.

[redtwin]

Thanks for the reply. I thought the starter would be spinning the engine quite quickly and I only guessed at the speed we were going (more concerned with running into the back of tow car).

It puzzled me for a week.