Cold Starting Problems

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Lacie
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Joined: Wed Jun 06, 2018 9:06 am

Cold Starting Problems

Post by Lacie »

Hi,

I'm having problems with my 406 coupe (2.0 16v).

Its a nightmare to start the car in the morning. I have to crank the car for a couple of seconds, 4 or 5 times until the car eventually starts (if I crank it for longer than a few seconds, it doesn't help). Then once it starts, the tickover is solid but if I press the accelerator it will die. Once it's been running for about a minute, everything is great. The revs are steady, and if I turn it off, I barely turn the key and it instantly starts. There is no smell of unburnt fuel from the exhaust and the fuel pump pressure is fine.

Could anyone offer any guidance on where to start looking for the problem? Thanks.
GingerMagic
3.0 24v
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Joined: Fri Apr 06, 2012 9:02 pm
Location: Bournemouth

Re: Cold Starting Problems

Post by GingerMagic »

Hi, welcome to the fold...

Truthfully I'm not sure about the petrol engines 406s, but if it was a diesel engine then I think the culprit would be a failing Coolant Temperature Sensor (CTS) which if faulty wouldn't tell the ECU that the car had a cold engine - therefore the ECU wouldn't add the extra fuel into the mix to start the car..... Once the engine is warm then the extra fuel isn't needed so the car starts fine.

Some engines have more than one Coolant sensor, but I'm afraid I can't be more specific....
2003 2.2hdi estate - mine
1998 Volvo 940 auto estate - also mine
2019 Citroen C3 something - the wife's
PP2000 user, can help with faults / diagnostics in the Bournemouth area.
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steve_earwig
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Re: Cold Starting Problems

Post by steve_earwig »

Hi there, welcome :mrgreen: It might be worth having a look at this http://www.406oc.co.uk/viewtopic.php?f=10&t=7050
Unskilled meddling sin©e 2007

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GingerMagic
3.0 24v
Posts: 3570
Joined: Fri Apr 06, 2012 9:02 pm
Location: Bournemouth

Re: Cold Starting Problems

Post by GingerMagic »

I've just got this from my friend Marcel.

If you have a later model Coupe, it's on the thermostat right hand side of the engine block. Just take the air filter box and silver engine cover off and access will be OK to change it :)

The older Coupe has 3 coolant sensors.

Hopefully Steve's guide will help you too.
2003 2.2hdi estate - mine
1998 Volvo 940 auto estate - also mine
2019 Citroen C3 something - the wife's
PP2000 user, can help with faults / diagnostics in the Bournemouth area.
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Doggy
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Re: Cold Starting Problems

Post by Doggy »

From personal experience if you want to prove the problem is due to a dodgy sensor without draining the system, get a new one and plug it into the connector without actually fitting it into the thermostat housing.

Obviously this won't work properly as the coolant warms up, but it will prove or disprove whether it helps cold starting and initial running quickly & cheaply.
2002 HDi 2.2 Exec Estate, (2008-12) (wonderful)
2003 HDi 2.2 6-speed Exec Estate (2012-19) (also a gem)
2009 Citroen C5 2.0 HDi VTR+ Estate (godawful heap)
2008 BMW E91 330i touring (great fun - murdered by a reversing SUV)
2007 BMW E91 325i touring (slower smoother quieter)
Lacie
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Joined: Wed Jun 06, 2018 9:06 am

Re: Cold Starting Problems

Post by Lacie »

Thank you for the help.

I've ordered a new coolant sensor so I'll update the thread as soon as it arrives.
Lacie
Newbie
Posts: 3
Joined: Wed Jun 06, 2018 9:06 am

Re: Cold Starting Problems

Post by Lacie »

Replaced the coolant sensor today and it hasn't made a difference, the engine still has to be turned over 5 or 6 times before it starts.

Any ideas where I should check next?
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