Topper article
By David Peacock,
The Mazda MX5 that came in recently was the exception to the rule. Once started in the morning it would carry on all day long running and starting without any problem until the next morning. Then it would take about 5 minutes of cranking and cursing to get it started, if left for two days the battery would go flat and it would have to be towed to get it started. Tuning the car uncovered nothing untoward, we paid special attention to the operation of parts that could cause cold starting problems such as poor Ignition output on cranking, starter motor and battery. Still nothing put it's hand up and said "IT'S ME", so we had to keep the car overnight to see what was going on the next morning. Sure enough the Mazda didn't want to start despite having plenty of sparks at the spark plugs at the right time, so the answer had to be on the fuelling side. the temp sensor was working OK, but as soon as an egg cup full of petrol was poured down the throat of the throttle the engine sprang straight into life. The problem then had to be a lack of petrol from the injectors on cold cranking. The ECU was tested to see if the fault lay here, but no fault was found. The Fuel pump was checked next - while it was good on output pressure it was lower than normal on suction from the petrol tank. This transpired to be the problem - a new petrol pump was the cure.