Birchall
Dick Chown Award 2016
Hi,
Our Daughter contacted me to say that her tdi was having problems starting mainly when cold.
I went over there this morning to try it myself and there was nothing wrong with the starter motor, the engine was cranking quickly but not firing.
My first thought was "Temperature Sender"
A quick VCDS scan confirmed it.
The reading was 30 degrees C and the car hasn't been used since yesterday afternoon.
This does prove that the first thing to check with starting problems is the coolant sender.
People often say "it can't be that the gauge reads correctly on the dash" but they forget that the sender has TWO circuits, one for the gauge and the other to feed the temperature to the ECU.
So if you are having starting problems (when hot or cold) then check the temperature sender.
If the engine is cold and the sender is "telling it" that the temperature is HOT, then the ECU will not set the correct mixture for a cold engine.
Vice versa for a hot engine, if the sender is telling the ECU that the engine is COLD it will enrich the mixture (too much).
They are not hugely expensive (always go for genuine Audi! since these senders are known to fail often, so you need the best and you can get your money back easier from Audi if and when they do!) And I am a confirmed eBay fan!!!
I know this is covered elsewhere on the forum, but it is well worth highlighting again, before people spend huge sums of money on the wrong parts.
Steve B
Our Daughter contacted me to say that her tdi was having problems starting mainly when cold.
I went over there this morning to try it myself and there was nothing wrong with the starter motor, the engine was cranking quickly but not firing.
My first thought was "Temperature Sender"
A quick VCDS scan confirmed it.
The reading was 30 degrees C and the car hasn't been used since yesterday afternoon.
This does prove that the first thing to check with starting problems is the coolant sender.
People often say "it can't be that the gauge reads correctly on the dash" but they forget that the sender has TWO circuits, one for the gauge and the other to feed the temperature to the ECU.
So if you are having starting problems (when hot or cold) then check the temperature sender.
If the engine is cold and the sender is "telling it" that the temperature is HOT, then the ECU will not set the correct mixture for a cold engine.
Vice versa for a hot engine, if the sender is telling the ECU that the engine is COLD it will enrich the mixture (too much).
They are not hugely expensive (always go for genuine Audi! since these senders are known to fail often, so you need the best and you can get your money back easier from Audi if and when they do!) And I am a confirmed eBay fan!!!
I know this is covered elsewhere on the forum, but it is well worth highlighting again, before people spend huge sums of money on the wrong parts.
Steve B
