I have a 2012 Citroën DS3 with port fuel injection and it experiences hard starting when hot combined with a smell of petrol fumes from the exhaust. No problems are experienced when the engine is cold. The dealer has suggested that the battery may be to blame (the replacement cost is about R1 000). Is this correct?
SJ HALL
via email
Answer: You did not give us the exact engine specification of the DS3 (1,2-litre or 1,6-litre; turbo or non-turbo) or explained the non-start event in detail. We assume that the engine cranks at the normal speed when it’s hot but then fails to fire. The following issues may contribute to a hot-starting problem on a petrol engine:
- A sensor issue, especially the engine coolant temperature (ECT) sensor: does the temperature gauge of the vehicle read the operating temperature when it’s hot? It’s best if the dealer conducts a full diagnostic check on the powertrain to eliminate the possibility of a sensor failure. Ask the technicians to read the ECT temperature sensor directly on the CAN bus of the vehicle. If the engine control unit (ECU) thinks the engine is still cold, it will inject too much fuel and the engine will not fire – which might also explain the fuel smell from the exhaust.
- Electrical issue: make sure the spark plugs receive sufficient voltage during the hot cranking event (check for spark). The resistance of some electrical components will increase with temperature and might be at a critical point during the hot-start event. This can include a timing pick-up sensor like a crank-position sensor, but that should also show up during the diagnostic check.
- Fuel delivery issue: it’s important that the correct amount of fuel is injected during the start. No fuel = the engine will fail to start. Judging by the unburned fuel smell, it sounds like the opposite is true – too much fuel being injected or no spark resulting in unburned fuel reaching the exhaust.
We doubt that the battery is the problem, as a cold-start condition is much worse on a dying battery than a hot-start event. You can have the battery checked for peace of mind.
