Injector back feed

[podwin]

Why does an injector that back feeds more than it should result in a difficult to start diesel engine?

[podwin]

But once started car runs fine.

I have read this on the interweb trying to find an answer, that an engine will run perfectly, no smoke and no noticeable drop in performance.

The only symptom being long cranking periods when the car has been left for some while.

What's the difference?

Is more fuel injected to just start the engine, which is never repeated even when running at full load?

[podwin]

That's what I said to the mechanic, but he said this, and from reading the internet he is right.

Glowplugs aren't needed that much to start common rail engines apparently, they do it via the injectors, although they are still used to speed warm-up.

This makes send to me, because the glow plug light barely registers on diesel nowadays, where as older diesels (pre common rail) I remember having to wait for the light to go out.

[podwin]

Very interesting.

Got the car back today, and he said the injectors were back feeding, but nothing to worry about and in-line with use they have had, and by all the same amount which is good.

So he went onto check the glowplugs, and none were working!

I'm sure it was quieter on the drive home.