Cold start problems on Laguna 2-litre

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Sun 30 Mar 2003 15:43
Cold start problems on Laguna 2-litre - Mike H
My father has a problem with cold starting on his Laguna estate, 2-litre 1996. It has been in the local Renault dealer for 4 weeks, and they have been singularly incapable of finding any faults. They have replaced the cat with no improvement, so put the old one back on. Ditto ECU. Ditto idle control unit. The diagnostic equipment fails to show any faults. The plugs are 4000 miles old. The cold start sensor is apparently OK. The car has done 84000 miles & has been regularly serviced since new. It might be relevant that the dealer also says it's running a bit rough when they do get it going. Starting when warm isn't usually a problem.

Has anyone got any bright ideas what the problem might be, as the dealer seems to be totally useless - they can't even be bothered to ring Renault UK for advice. Alternatively, can anyone recommend a good Renault specialist (or even a decent dealer) in the Portsmouth area.
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Sun 30 Mar 2003 20:34
Cold start problems on Laguna 2-litre - Andrew Moorey (Tune-Up)
CXhief suspect is the coolant temperature sensor. They only have to be slightly out to prevent starting. Be prepared for some fun and games at Renault as there are three different types available; two NTC and one PTC key difference visually is one type is black the other white.
You could try our man Alvin Tarlton in Southampton (Yellow Pages)
Andrew



Happiness is a T70 at full chat!
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Sun 30 Mar 2003 21:12
Cold start problems on Laguna 2-litre - Mike H
Andrew, what do you mean by "PTC" and "NTC"?

I specifically asked him about this component & he has been assured by the dealer that their diagnostic equipment claims it's functioning perfectly.
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Tue 1 Apr 2003 07:20
Cold start problems on Laguna 2-litre - Andrew Moorey (Tune-Up)
Sorry, PTC is Positive Temperature Co-efficient NTC for Negative Temp Co-eff. All it means is that the resistance inside the sensor changes in different ways, one increases in resistance as temp increases the other decreases. I'm still of the opinion that this is where to start because if the sensor is slightly out it won't trigger a fault code as it is still within its' operating perameter. It would only show up if it went open or short circuit. You need to be in a position to know the temperature of the engine and either measure the resistance or the voltage at the sensor and compare it to spec.
Andrew



Happiness is a T70 at full chat!
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Tue 1 Apr 2003 13:23
Cold start problems on Laguna 2-litre - Mike H
Trouble is, it's stuck at the main dealer's, and has been for 4 weeks......luckily my father has borrowed some alternative transport, as they don't seem in any rush to fix it, and their communication is rubbish. They have apparently called in an "expert" from Renault UK who is going to look at it. Pulling it out at this stage still means that he'll have to pay a hefty labour bill, so I think we'll leave it for another couple of days & then beat them up again. I asked home to mention the temperature sensor but not sure whether he has or not.

Thanks for the tip anyway, it would have been my first choice given what else they've done.
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