fiesta cold start problem
Colin
Hi,
Car is difficult to start when it is cold in the morning. Only had the car a
couple of weeks and the first morning I tried to start it and it just
wouldn't catch, starter was turning over OK, just wasn't catching. Gave up
after about 15 mins. and went to work. Got home that night and it started
first time. It was quite warm during the day, so this got me thinking that
perhaps there was perhaps some moisture present that was affecting the cold
start. Next morning was just as chilly and it was the same story. Got a can
of 'wet start' from Halfords sprayed it on the obvious places and -hey
presto- started fine next morning. Not quite as cold this morning though I
noted. Next morning was colder again and the problem returned, eventually
got the car started after about 10 mins though.
On Friday past I decided to get Ford to run a diagnostic on the car since I
now suspected an ECU problem of some sort. They got back to me and said that
the problem was being caused by the Throttle position sensor' (TPS). Went
away for the weekend and got back on Monday night, so the car hadn't been
used for 3 days, Tuesday morning (very mild) car starts first time.
Wednesday morning (again, very mild) car starts first time.
Mmmmm, surely this TPS isn't temperature sensitive?? Started doing a bit of
detective work and most problems caused by the TPS being faulty are the car
cutting out or stalling; or high revving, can't find anything where 'cold
starting' is a problem.
Is it more likely to be a problem related to the coolant temperature sensor,
or the inlet air temperature sensor. Applying my logic to this, these seem
temperature sensitive and are linked, I think, to the ignition system.
Any opinions welcome
Cheers,
Colin
Colin
been changed and the air inlet cleaned out and the fuel filter has been
changed.
Cheers,
Colin
martin.shaw11
Regards
Martin
Tim..
"Colin" <c...@gringo97.fsnet.co.uk> wrote in message
news:anfvq4$a18$1...@newsg3.svr.pol.co.uk...
sing by the starter motor and check the coil pack (back of engine where the
dizzy used to be mounted) is clean (wash off with brake cleaner or similar
solvent, its connection is sound and the HT leads are in good order. If you
get the weak HT leads syndrome of missfiring under load when its damp then
change them- use only Bosch / Lucas or Ford ones. If the car wont start in
the relatively warmish mornings we have at the moment, its not going to have
much chance of doing so in december / january!
Does the car appear flooded when it wont start, - exhaust smelling of
petrol, or does it seem to be lack of spark? If there is no spark and no
fuel being injected then go straight to the crank sensor and that the ECU is
powering up.
Tim..
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Colin
Thanks for the replies, I'll have a check at the crank angle sensor as
suggested. Out of interest, what does that do? The HT leads are fine, no
problems there, damp conditions aren't a problem, just the cold!! As you
mentioned starting in December/ January will be a problem but it was
anything but mild last week up here in chilly Scotland when the problem
first came to light. ;-)
Getting back to the original querie, Ford have said that the TPS is at fault
and applying my basic logic to things I just can't see it. It makes sense to
me that it is more likely to be a temperature sensor fault. But I am no
expert and my knowledge is fairly basic.
Cheers,
Colin
Racker
wrote:
>Fiesta 1.1i 1994 L Reg.
>
>Hi,
>
>Car is difficult to start when it is cold in the morning.
>
Stab in the dark.
Have you checked the battery? if its got a cell down there might not
be enough guts in it to run the fuel/ignition system when the starter
is operated.
Colin
that has been tightened up.
Tim..
"Colin" <r...@royeaston.fsbusiness.co.uk> wrote in message
news:anh1rf$ank$1...@news6.svr.pol.co.uk...
default value. If the car still struggles to start when cold then its ok.
What I forgot about is a faulty Coolant Temp Sensor. If this fails, or goes
closed or open circuit the ECU will again use a default value which is
always that for a 90% hot engine- thus trying to start from cold will be
difficult as the mixture wont be rich enough and it wont impliment a fast
idle. Tell tale signs are that when it does start you will notice it to be
hesitant and spluttery til warms.
Colin
> As a test you can unplug the TPS connector which will force the ECU to use
a
> default value. If the car still struggles to start when cold then its ok.
>
> What I forgot about is a faulty Coolant Temp Sensor. If this fails, or
goes
> closed or open circuit the ECU will again use a default value which is
> always that for a 90% hot engine- thus trying to start from cold will be
> difficult as the mixture wont be rich enough and it wont impliment a fast
> idle. Tell tale signs are that when it does start you will notice it to be
> hesitant and spluttery til warms.
Thanks for that Tim. What you have described is exactly what happens when
the car eventually does start from cold. Driving immediately after the car
starts it is very hesitant and spluttery as if the mix isn't rich enough as
you said. My first thought when this happened, before I knew more about the
sensors, was that maybe the fuel pump was faulty but the ECT seems the
favourite to me.
It's started first time the last 4 days when the temperature has been around
10 degrees C, last week when the problem came to light the temp. must have
been below 5 degrees. Not sure if the sensor would be sending a false
reading to the ECU until a certain temperature is reached.
What would happen if I unplugged the ECT sensor? would the ECU just take a
mid-range value for injecting the fuel? Or is this a bad idea?
Colin
Tim..
the ECU is using default value all the time (which is that of an engine at
about 80o C) OR the CTS is giving a stupid reading to the ECU at low
temps. Both are possible. What you need to do is have alook at the multi
plug on the CTS for bad connection and then hook up your DVM to the signal
wire (one will be at 5v all the time, the other is the signal to the ECU) it
when the temp is well cold and see wot it reads. You should get about 4v
when cold, dropping smoothly to about 0.7v when the engine is very hot. Any
glitches or total open circuit and it needs replacing. They are about £18
from the dealer so not expensive.
The other simialr fault with the CFI engines is the Air temp sensor on the
under side of the air cleaner. These can fail too but usually cause flooding
symptoms on a cold engine. The CFI engine is prone to backfires now and
then and this melts the ATS in the aircleaner which knackers it. Check it as
well.
John Drews
automatic choke > >this may help your car start better in the mornings
and may save u a fortune on damp start
from john drews
PJML
>
> Try altering your your cut in point and cut off point on your
> automatic choke > >this may help your car start better in the mornings
> and may save u a fortune on damp start
> from john drews
Given that the original poster mentioned throttle-
position-sensors and ECUs, I'd bet a fistful of
Railtrack shares that there is no "automatic choke"
on his engine... it's injected!