Engine wont run properly when very cold

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smithy318i
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Wed Feb 20, 2008 7:19 am

It was -5 Celsius (23 Fahrenheit) outside this morning and my car refused to start at the 1st attempt. When it started, the idle was around 500 and it would stall if left it alone while i scraped the windscreen.

It also stalled and refused to restart once i had driven it about a mile.

Are these symptoms of a duff blue temperature sensor?

another odd running issue is if I come back to the car 30 minutes after driving it, the engine will run badly and stall continuously.
Last edited by smithy318i on Wed Feb 20, 2008 10:46 am, edited 1 time in total.
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Brianmoooore
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Wed Feb 20, 2008 10:29 am

Not the usual way they fail, but it's still the first thing to try.
TPS is also suspect - cold thickening up any goo inside of it?
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Stan0870
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Wed Feb 20, 2008 8:34 pm

hello mate,has the car ever done this before in the cold? an do you buy your fuel at the same place every time? basically do you use super market petrol?
smithy318i
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Thu Feb 21, 2008 4:14 pm

did it again today. Im thinking fuel pump relay.

I get my fuel from all different places (most recent was Total)
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Stan0870
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Thu Feb 21, 2008 8:47 pm

as brian suggested try the throttle position sensor first, then have a stab at the fuel pump relay if you think that it might be causing a problem, their quite easy to test if you have access to a pocket multi meter. do you know when the fuel filter was last changed? and check, if you have access to some where flat to take the back wheel off?, (tank side) an check the tank neck as there prone to coroding by there, because crud gets jammed behind the plastic cover an rots the neck out which contaminates the fuel. im not near as technically minded as mr moore, so i cant help you much with the electrical side of things, you need a guru. but i am tight thats why i check all the dont cost much money things first. its wort a stab.. best of luck m8...
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Brianmoooore
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Thu Feb 21, 2008 9:17 pm

Fuel pump relay can be swapped with any other orange one in the fusebox.
smithy318i
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Sat Feb 23, 2008 7:25 am

It wasn't the fuel relay.

If the CPS is faulty would the fuel pump run when cranking the engine?
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Brianmoooore
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Sat Feb 23, 2008 10:50 am

Fuel pump won't run without signals from the TPS, but they don't have to be the correct signals. Noise from an intermittant one can still trigger the pump relay.
Have you changed that blue sensor? (Or, knowing you're handy with a soldering iron, temporarily replace it with a 4.7k pot in series with a 150 ohm resistor, and adjust it as the engine warms up)
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