Cold starting problems - diesel engine

mikey72

Rotor wrote: »

thanks for replies everyone.
Yea - battery good ; turns over fast and for long time
With the timer relay - would that mean the pigtail light on the dash wasn't on for very long because it seems to be on for a reasonable lenght of time ( havn't noticed it being on for a shorter duration).

As for the coolant temp sensor that got me thinking. Same garage recently looked for leak of coolant (I have had to keep topping up expansion chamber) and they pressure tested the cylinders. Possible link?

The timer for the light and the actual timer for the glowplugs aren't usually related.
If the compression is down, it won't start very well either, even with good glow plugs.

Rolandtheroadie

It could be a multitude of things once you've cancelled out the basics.
I tested my glowplugs by using a metre set to ohms. 2 came back faulty, changed them and it's started great ever since.
The wifes does the same as you state in your OP to the letter. The reading I've done trying to find a solution mentions injectors, fuel running back to the tank overnight, worn rings/seals. All expensive stuff, it was probably -4 here this morning and it still started.
I've a wee experiment to do tonight with loft insulation but it doesnt involve the battery lol.

Rotor

Pew_Pew_Pew_Lasers! wrote: »

The glowplugs may be fine but the glowplug relay may not. If you're competent you can wire all four glowplugs directly from your own power source, and see if the engine fires. If it does, you know the fault lies with the relay. If it still won't fire, the problem is elsewhere. Lack of fuel, perhaps, or ECU missing a signal.

Get someone to turn the key to the glowplug heating position, and measure for 12V at each glowplug.

Sadly I don't think i'm competent for that. Guess it's off to the specialist

Pew_Pew_Pew_Lasers!

Don't worry too much, there isn't a lot that can prevent a diesel from firing.

Stephen_Leak

hartcjhart wrote: »

try turning ignition on when the glowplug lights go out turn off then turn on again and wait till the light goes out,this will give the glow plugs a 'double' warm up and should do the trick

I was going to suggest - as I was always told to do with oil burners - the "single" version of this. To switch the ignition on, wait for the glow plug warning light to go out, and then start the engine.

Dick_Turpin99

scotsman4th wrote: »

It could be a multitude of things once you've cancelled out the basics.
I tested my glowplugs by using a metre set to ohms. 2 came back faulty, changed them and it's started great ever since.
The wifes does the same as you state in your OP to the letter. The reading I've done trying to find a solution mentions injectors, fuel running back to the tank overnight, worn rings/seals. All expensive stuff, it was probably -4 here this morning and it still started.
I've a wee experiment to do tonight with loft insulation but it doesnt involve the battery lol.

As Scotsman correctly states it could be diesel is not delivering on time, as if it is leaking back, maybe through a faulty lift-pump check-valve or from a loose/perished fuel hose on the low pressure/suction side to the fuel tank. This could be checked by including a piece of clear plastic pipe in the fuel line to identify is diesel has leaked back

When you try to start it soes smoke immediately from the exhaust pipe, if not it would indicate fuel is not delivering immediately.

If the rings were worn it would consume engine oil and also run very smoky.

Alternatively if it has a BOSCH fuel pump it maybe the cold-start advance device (known as KKSB) which on some fuel pumps have been known to seize/fail

Rotor

Well it was minus 4 this morning and the car started easily ! The only change i've made is to park the car on a slope ( back end highest)
Does this suggest the fuel is leaking back to the tank? (I'd squeeze the primer pump to check but the RAC cut it out when it split)

esmerobbo

Rotor wrote: »

Well it was minus 4 this morning and the car started easily ! The only change i've made is to park the car on a slope ( back end highest)
Does this suggest the fuel is leaking back to the tank? (I'd squeeze the primer pump to check but the RAC cut it out when it split)

Quite possible but do it for a few days to see it wasn't just random. Then try and find the reason for the run back if it is.

mikey72

Replace the leak off pipes.

Dick_Turpin99

mikey72 wrote: »

Replace the leak off pipes.

Do they return to the filter head or to the fuel tank? essentially they're after the point of injection so I'm trying to figure out how it would cause leak-back in the fuel delivery line.


The fact that it starts without the lift-pump would tend to indicate that the fault lies within that component.....essentially its only needed when changing the fuel filters....if it works ok without it drive on and see if the fault develops any further