406oc.co.uk

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.

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....

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

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.

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.

Thank you for the help.

I've ordered a new coolant sensor so I'll update the thread as soon as it arrives.

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?