Quote from: Markits more likely fuel starvation caused by either air ingress or fuel running back from the pump.

But would this not happen when the engine is also cold?

Quote from: MarkThe glow plugs have nothing to do with it when its warm tbh

I was thinking maybe hes leaving it 20 min so its not quite Hot (just warm) so it needs a little heat

chris, when you say HOT..... does it do it if you turn it off and start it right up again when its hot ?

the real problem is, that theres no problem when its cold

id think any fule/air leak problem would be even more pronounced when cold (and its been left a long time)

the turbo will make no difference to the starting, wastgate jammed fully open or fully closed should make no difference at starting revs ? )or close enough to nothing anyway)

unless....... the timine is out ?

or.... how long have you had it ? maybe someone before you put petrol in it ?
petrol in the diesel and it will pretty much run ok cold, but when its hot youll get pre-detonation due to the heat and pressure in a diesel engine and the lower heat/pressure detonation point of petrol ?

Quote from: filbert

Quote from: Markits more likely fuel starvation caused by either air ingress or fuel running back from the pump.

But would this not happen when the engine is also cold?

No- if it is wear on the pump the hotter the car gets the more fuel will leak by and the less efficient it will be at drawing diesel - remember the pistons and pump housing are made out of two different types of metal (Steel and aluminum)

There is also a cold start system that makes starting from cold easier on the XUD (As with all diesels) - this also would make it easier to start when temperature is low or if it has been sitting.

Also, If there is a fault with the injectors they may well need the glowplugs to start easier, and the hotter the car gets the less time the plugs are lit for.

There is another very simple cause - slow cranking speed caused by a bollocksed motor.

Quote from: knighty

Quote from: MarkThe glow plugs have nothing to do with it when its warm tbh

I was thinking maybe hes leaving it 20 min so its not quite Hot (just warm) so it needs a little heat

chris, when you say HOT..... does it do it if you turn it off and start it right up again when its hot ?

the real problem is, that theres no problem when its cold

id think any fule/air leak problem would be even more pronounced when cold (and its been left a long time)

the turbo will make no difference to the starting, wastgate jammed fully open or fully closed should make no difference at starting revs ? )or close enough to nothing anyway)

unless....... the timine is out ?

or.... how long have you had it ? maybe someone before you put petrol in it ?
petrol in the diesel and it will pretty much run ok cold, but when its hot youll get pre-detonation due to the heat and pressure in a diesel engine and the lower heat/pressure detonation point of petrol ?

If you get enough petrol in it it will destroy the injector pump - diesel is what lubricates the pump - Ive seen many a siezed pump from morons who have put petrol in to clean the injectors

well I started it hot monday morning when i went to work - pulled up after a 30min drive, turned engine off, went to get a car pass for a minuite or 2, then got back in, plugged in the code, waited for the glow plug lamp to go off, and started up without a problem... maybe took about a second more than it does when cold.

On friday, however, it wouldnt start for love nor money after about a 30-40 minute wait... but im not sure if that was just where i had buggered up the immobiliser sequence

That afternoon, too, it had had struggled to start after about a 4hr wait which i thought was unusual.  it seems to be imporving as i build up a relationship with the car though.

The first thing to do is get rid of the immobiliser - the 406 one gives an awful lot of bother

Quote from: MarkNo- if it is wear on the pump the hotter the car gets the more fuel will leak by and the less efficient it will be at drawing diesel - remember the pistons and pump housing are made out of two different types of metal (Steel and aluminum)

But doesnt the 406 have a rotary injection pump?(not an inline with pistons)

Im still stuck in the tractor age - havent used inline pumps for years.

That was an if after all!

But the fact that there is a cold start system allows for hot starting issues. as does the ball bearing on a spring non return valve...

doesen;t the cold start on a diesel just advance the timeing slightly ?

I guess if it was permenantly enguages it could cause hot start problems like he described ?

after 5 min of engine off, its hot enough to start anyway

after 30 min its cooling and wont start

after an hour its cool enough to start ?

(bit of a wild guess tbh)

The cold start increases the idle speed as well - if you look on the bosch pump while its warming you can see the cable slacken.

if its REALLY cold it also advances the timing.