Cold Starting Problems

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Lacie
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Cold Starting Problems

Post by Lacie » Wed Jun 06, 2018 9:17 am

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.

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GingerMagic
3.0 24v
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Location: Bournemouth

Re: Cold Starting Problems

Post by GingerMagic » Thu Jun 07, 2018 6:14 pm

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....
1999 T4 family wagon
2002 Citroen Xsara Picasso Hdi90
2003 Hdi110 Executive estate
1998 406 V6 Coupe - Midlife crisis..!
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 » Thu Jun 07, 2018 7:20 pm

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

2004 D9 2.0 HDi 110 Estate lhd VF38ERHZF81657352 - sold but being very well looked after.
1991 Yamaha TDM850 - fuel leaks galore!
2008 Toyota Recall4 2.0 VVTI ATM LHD JTMBH31V90D007261 - flimsy piece of crap.
1953 Matchless G3LS - It's alive!!

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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 » Thu Jun 07, 2018 8:25 pm

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.
1999 T4 family wagon
2002 Citroen Xsara Picasso Hdi90
2003 Hdi110 Executive estate
1998 406 V6 Coupe - Midlife crisis..!
PP2000 user, can help with faults / diagnostics in the Bournemouth area.

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Doggy
Mod with a 2.2 HDi, De-Fapped!
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Location: Northants

Re: Cold Starting Problems

Post by Doggy » Fri Jun 08, 2018 10:49 pm

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.
2003 HDi 2.2 6-speed Exec Estate

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

Re: Cold Starting Problems

Post by Lacie » Sat Jun 09, 2018 5:57 pm

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 » Sun Jun 17, 2018 10:53 pm

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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