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Mk 3 Fiesta Starting Issues.


Ren
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Hey Everyone.

Hopefully someone out there will be able to answer this question as it has been driving me crazy.

I have a L registration (1994) 1.1 Litre Ford Fiesta (Model: Fiesta Summer SVP) that simply refuses to start when it isnt a really warm day (i.e. above 20 degrees C). It is a Central Fuel Injector engine. It seems the only way to get her started is to either pour some fuel directly into the top of the injector or spray some easy start (ether) into the intake.

So far things that we have tried include:

1) Replace spark plugs

2) Replace intake air Manifold Temperature Sensor

3) Replaced cam shaft position sensor

4) Replaced silencer box

5) Removed catalytic converter

The car (ruby being her name as she is red) runs just fine once you have got her started but just struggles to get over this initial hurdle if its not warm.

It seems that she is just running to lean on startup. Does anyone have any ideas what might be the root cause of this?

Any answers/thoughts/theories/wild imaginings are welcome.

Thanks in advance everyone.

Ren

:)

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Hey Everyone.

Hopefully someone out there will be able to answer this question as it has been driving me crazy.

I have a L registration (1994) 1.1 Litre Ford Fiesta (Model: Fiesta Summer SVP) that simply refuses to start when it isnt a really warm day (i.e. above 20 degrees C). It is a Central Fuel Injector engine. It seems the only way to get her started is to either pour some fuel directly into the top of the injector or spray some easy start (ether) into the intake.

So far things that we have tried include:

1) Replace spark plugs

2) Replace intake air Manifold Temperature Sensor

3) Replaced cam shaft position sensor

4) Replaced silencer box

5) Removed catalytic converter

The car (ruby being her name as she is red) runs just fine once you have got her started but just struggles to get over this initial hurdle if its not warm.

It seems that she is just running to lean on startup. Does anyone have any ideas what might be the root cause of this?

Any answers/thoughts/theories/wild imaginings are welcome.

Thanks in advance everyone.

Ren

:)

Hi Ren,I am almost certain your problem is being caused by a faulty Coolant temp sensor,(don't get confused with the sender unit which monitors the coolant temp and sends the temp reading to the dash),this sensor works within the engine management system.And yes you are correct in saying the car in running lean on start up because the temp sensor is telling the ECU that the engine is hot and therefore requires less fuel,but once the engine is genuinly hot it would start ok. hope this has been helpful.

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Hi Ren,I am almost certain your problem is being caused by a faulty Coolant temp sensor,(don't get confused with the sender unit which monitors the coolant temp and sends the temp reading to the dash),this sensor works within the engine management system.And yes you are correct in saying the car in running lean on start up because the temp sensor is telling the ECU that the engine is hot and therefore requires less fuel,but once the engine is genuinly hot it would start ok. hope this has been helpful.

Thank you so much for the response. I should hav mentioned that we have also replaced the coolant temperature sensor. However what you have mentioned makes a lot of sense as the other day the engine overheated as the fan did not kick in while we were sitting in traffic.

When looking at the sensor i noted that the wires immediately upstream of the plug were looking seriously worse for wear (i.e. the insulation was completely split on both wires).

I repaired the insulation with some heat shrink but it is possible that the system is still not working correctly.

How would one go about testing if the sensor is working?

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Thank you so much for the response. I should hav mentioned that we have also replaced the coolant temperature sensor. However what you have mentioned makes a lot of sense as the other day the engine overheated as the fan did not kick in while we were sitting in traffic.

When looking at the sensor i noted that the wires immediately upstream of the plug were looking seriously worse for wear (i.e. the insulation was completely split on both wires).

I repaired the insulation with some heat shrink but it is possible that the system is still not working correctly.

How would one go about testing if the sensor is working?

It is possible to have got a faulty sensor,but you've now mentioned the insulation around the wires is looking shoddy, check all the loom as best you can especially were there is a lot of heat and where water could of penetrated the loom.As for testing the sensor the only reliable way would be to connect up to a diagnostic tester which is capable of live data logging, I could give you values what you are supposed to be getting at the sensor connector but this isn't testing the sensor itself,you could test the continuity of the circuit ie. from the sensor plug to the ECU plug if you have a descent multimeter# BUT BE VERY CAREFUL AT THE ECU END #without looking at the wireing diagram i'm not sure what pins or wire colours you would have to probe.supply mobile number and we can talk.

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It is possible to have got a faulty sensor,but you've now mentioned the insulation around the wires is looking shoddy, check all the loom as best you can especially were there is a lot of heat and where water could of penetrated the loom.As for testing the sensor the only reliable way would be to connect up to a diagnostic tester which is capable of live data logging, I could give you values what you are supposed to be getting at the sensor connector but this isn't testing the sensor itself,you could test the continuity of the circuit ie. from the sensor plug to the ECU plug if you have a descent multimeter# BUT BE VERY CAREFUL AT THE ECU END #without looking at the wireing diagram i'm not sure what pins or wire colours you would have to probe.supply mobile number and we can talk.

Thanks Carlo

I will check the rest of the loom and probably the pins in the connector as well (in the dayight) to ensure there is no shorting out on the line.

I will have to go and get myself a decent multimter.

thanks for your help and to quote the governator.....

"I'll be back"

Ren

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