First off, welcome to the forum
Second, you're saying that if you cool the inside of the car, the tapping sound goes away?
Yes, it doesn't sound like this is caused by the direct injection fuel pump. That goes away quite quickly after startup. You can hear the rather noisy high pressure fuel pump for the direct injectors as soon as you start the car cold. After a short period of time, the engine RPM and the sound of the engine will change. This is when the engine switches from direct injection to port injection.
Have you been able to localize where the sound is coming from?
When it's loudest, can it be heard if you're standing outside the car with the doors and windows closed?
The reason I ask is there has been a couple of times I have read about exhaust heat shields that were not attached completely. You did, however, mention about the cooling of the interior and it not being there when the outside temperature was lower. It could be HVAC duct system issue and colder air will change the characteristics of this duct work. You said it's changes its tapping rate with the engine RPM. Does it also change with fan speed changes?
Second, you're saying that if you cool the inside of the car, the tapping sound goes away?
Yes, it doesn't sound like this is caused by the direct injection fuel pump. That goes away quite quickly after startup. You can hear the rather noisy high pressure fuel pump for the direct injectors as soon as you start the car cold. After a short period of time, the engine RPM and the sound of the engine will change. This is when the engine switches from direct injection to port injection.
Have you been able to localize where the sound is coming from?
When it's loudest, can it be heard if you're standing outside the car with the doors and windows closed?
The reason I ask is there has been a couple of times I have read about exhaust heat shields that were not attached completely. You did, however, mention about the cooling of the interior and it not being there when the outside temperature was lower. It could be HVAC duct system issue and colder air will change the characteristics of this duct work. You said it's changes its tapping rate with the engine RPM. Does it also change with fan speed changes?
