Cold start problem

[thatch]

Hi Guys. I have a 2008 avensis 2.0d4d with 200k on the clock. Recently it struggles to start when cold. It will start for a second or 2 take no rev and die out. Does this about 6 or 7 times then eventually stays going a bit rough for a few seconds then go the best. Doesn't matter how many times I turn on and off to the heater light goes out. Starts perfect every time when warm. Any ideas? 

Thanks 

[paul9]

Possibly a glow plug or two died on you. At least that's one of the common causes of hard starting in diesels.

[Notoyboy]

I would second that 😊

Check the glowplugs are working before you dig any further - they don't last forever

[thatch]

Thanks guys. Will try them first! 

[paul9]

Also, if you are using suspect diesel or vegetable oil as fuel, that can also cause hard cold start issues. Some countries or regions don't have the best of control over fuel supplies and some individual fuel stations can be bad. Maybe a different supplier could make a difference for you, once any potentially poor fuel is out of your system.

[thatch]

On 10/26/2019 at 2:13 PM, Notoyboy said:

I would second that 😊

Check the glowplugs are working before you dig any further - they don't last forever

So I changed the glow plugs but the problem persists! Next stop is look at the glow plug relay. Anyone any idea where I can find it on the car? Thanks

[paul9]

To be honest, you should have tested the glow plugs, not just arbitrarily changed them. It is still a good idea to test the replacement plugs, and the power supply rail to them before you start digging into the relays and fuses. Not sure on where those are located but there is a box between the air filter and bulkhead, and another one behind the glovebox on my right hand drive 2007 and I think there are some fuses and relays by the OBD2 port which is pretty much behind the bonnet release. The glovebox fusebox has a fuse listing, the other ones should have, too.

[Notoyboy]

A quick way to test if the glowplugs are receiving voltage on start up is to simply connect a voltmeter between the supply rail (or 1 of the glowplugs) and earth, whilst someone turns the key.  This would confirm the relay/control is working, though not how worn the relay's contacts might be.

Based on my experience with a Citroen diesel, I'd expect maybe 10-12 volts initially, dropping away to 9-10 volts (dependent on state of battery).  The voltage drops as the glowplugs' resistance increases as they heat up.