Hi. I've been experiencing trouble starting my car just a week after doing a timing belt and sump service on my Audi A4 2.0 TFSI. This service has been done 2 years back and I've been experiencing this problem for 2 years now. The car's check engine light just suddenly stopped working at the same time when the car started having issues starting. I'm guessing there must be a relation between the CEL & starting issues. I'm not sure if there's any relation to this problem due to the timing service. I've done numerous diagnostics which shows "fuel open circuit" however nobody has been able to fix the problem for the past 2 years. When the key is left in the on position for a good few minutes after that I cycle the key and the in-tank fuel pump primes and the car starts immediately without hard starting. However the key has to be left on the "On" position for a considerable amount of time. Also when the car is started and hot it starts right back up again. CEL has never worked since.
My car has 169000 miles.
My car has a manual transmission.
If you have the cam belt timing off, it will make the car difficult to start, but that wouldn’t effect the fuel pump function. and you would notice that the car runs poorly when it is running. So from here it doesn’t seem like the timing belt service is related to your problem. When you turn the key on, the main relay activates the ECU. When you turn the key to the start position, the ECU should activate the fuel pump relay and run the fuel pump. When you release the key from start, the fuel pump relay will shut off unless it senses an RPM signal that indicates the engine is running, in that case, it keeps the relay on and the fuel pump running. It sounds as though you have a problem in that chain of events. Your fault may be in the main relay, the fuel pump relay, or even the ignition switch itself. As for the Check Engine Light: when you turn on the key, the check engine light should come on, then go out when you start the car. This is a bulb check feature, so if the CEL is not coming on, you should check the bulb. If changing the bulb does not make it work, then you may have a problem in your instrument cluster or your ECU. If you run a scan with the appropriate equipment, the data stream will tell you if the ECU is trying to turn on the check engine light. Either way, the ECU will still store codes that can be retrieved. I’m not suggesting that you run out and buy a handful of relays. These parts are pretty expensive and might not even be the problem. What you need is a systematic diagnosis by someone who knows the system well. If you contact Your Mechanic, they can send a technician to your home or office who will be able to check out your hard starting issue and let you know what can be done about it.
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