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Felicia cold start problem


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#1 richardmac12345

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Posted 23 December 2009 - 21:10

Hi,

I have a skoda felicia 1.3 which is very hard to start when cold but runs ok after being driven for two miles.

I have checked the resistance of the Cold Temperature Sensor and it reads 5000 ohm when cold and 300 ohm when hot ( I measured this by taking it out and heating it with a kettle) this resistance fits the specification so I think that this device is ok.

I have had a friend read the fault code and it states that there is no signal from the camshaft ( Hall sensor). There is no camshaft sensor on my car but there is a Hall Sensor. I am not convinced that this is the problem because the car is fine after being driven for two miles and if the Hall sensor was faulty it would still give problems when being driven. Also, I have a Strobe light and have connected it to a spark plug and the strobe lights as I try to start from cold, therefore I conclude that the Hall Sensor is giving a signal. The fault code could be an old code from the past that was not removed.

Please could anyone advise me on this fault. Could it be the hall sensor? Maybe the voltage to the Hall sensor picks up once I have started the car or something!

Thanks,

Richard.

#2 TeflonTom

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Posted 23 December 2009 - 23:07

if there were no signal from the hall sender the engine would not run. full stop

if the coolant sensor is working ok it may be down to the valve clearances being too tight

#3 djaychela

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Posted 23 December 2009 - 23:22

Yeah, as Tom says, the Hall Sensor is a show-stopper. And also as he says, check the valve clearances; they can make a big difference to the engine's running, and will change with temperature.

Can you do a compression test - one cold and one hot?

#4 fordfan

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Posted 29 December 2009 - 07:09

There is a wiring modification that can be done, where the wire on the engine coolant temperature sensor that forms the earth part of the circuit to the ECU (I think the brown/white - you'll need to check this), is spliced into (not cut) with an additional wire and connected to the battery negative terminal. Also an extra earth to the engine (with a heavy duty cable) is added.

We have used this in the past to cure poor cold starting after the usual options (dirty throttle body/air filter, valve clearances, broken thermostat, dodgy engine coolant temperature sensor etc.) have been looked at.

#5 richardmac12345

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Posted 05 January 2010 - 21:05

if there were no signal from the hall sender the engine would not run. full stop

if the coolant sensor is working ok it may be down to the valve clearances being too tight



#6 richardmac12345

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Posted 05 January 2010 - 21:06

Thanks for this information

#7 richardmac12345

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Posted 05 January 2010 - 21:09

There is a wiring modification that can be done, where the wire on the engine coolant temperature sensor that forms the earth part of the circuit to the ECU (I think the brown/white - you'll need to check this), is spliced into (not cut) with an additional wire and connected to the battery negative terminal. Also an extra earth to the engine (with a heavy duty cable) is added.

We have used this in the past to cure poor cold starting after the usual options (dirty throttle body/air filter, valve clearances, broken thermostat, dodgy engine coolant temperature sensor etc.) have been looked at.