Diesel starting problem.

Is there a stepper motor connected to the injection pump? ISTR something about 3 settings: 1 for off, 1 for starting, 1 for running. It might not move to the "starting" position when you're trying to start it but then does move to "running" when you release the key......? Something like that.

Warning: I may be talking bollox.

Si

Thanks, but browsing through the Haynes manual I can't find any mention of a stepper motor, it just appears to use a bog standard Bosch fuel pump.

Ok, are you able to check that power's getting to the fuel pump while you're turning it over? I'm assuming it's electric - I haven't played much with diesels.

Si

It's driven by the cambelt, that's why I'm puzzled, as I would have thought that the engine would be much more likely to fire when it's being turned over.

Yes, you said it was clockwork...

Fuctifino then, sorry. SWKWBAS

Si

Well you may have a very small air leak or more likely the transfer pump from the tank is taking a little while to come up to pressure. You could try hot wiring it to eliminate that from the equation.

There's still an electrically operated solinoid on the pump to switch off the fuel supply. There could be a fault in the ignition switch. You'll need to check the connection on the solinoid while someone turns over the engine.

John

Again another item I can't find any mention of in the Haynes manual.

If you remember Duncan this was the engine where I couldn't quite align the timing marks on the fuel pump when I changed the cambelt, due to a very powerful internal spring pulling the pump forward every time the marks came into close alignment, so I eventually left it in its original position of about one notch before the marks were aligned.

Although the actual running and performance appear fine, however do you think that this could be connected to the problem?

MIght be but you'd probably notice the power drop if it was a tooth out. The transfer pump should be on the Haynes diagram, IIRC it's in the fuel tank

Could the stop solenoid be a bit sticky, so that it needs the full voltage to operate, which it won't get while the starter motor is churning?

You could try taking the solenoid plunger out. Establish beforehand how to stop the engine with the plunger absent - some injection pumps have a lever for the purpose.

Peter

Checking through the Haynes manual for this engine, as far as I can gather what they refer to as a 'lift pump' isn't fitted to my particular vehicle (H reg Astra estate).

I'm fairly certain it had one. I'd still bet on the air leak first though. Snag is it could be all sorts of s*it, the other notoriuos failure modes where the electric relays & the valve clearance.