I have a 2003 Nissan 350z and its a underwater salvage from Katrina. I have had the car for about 2 months now and have put prolly around 20,000 miles on the car. I didnt notice this tapping noise until about 4 weeks ago. I didnt pay it much attention cause i just thought it was the lifters tapping considering it only did it on a cold start. So the only time i ever heard it was when i was leaving for work in the am and going home once i got off work. It happened as soon as the car started and lasted for a hard 5 seconds and then goes quite. I searched this thread and others for this same problem and havent found anything on it. Do you guys think it may be the timing chains or the lifters. Or if any of you guys have experienced this problem i would appreciate the advice. thanks.

 

i was able to find people with similar problems. like tapping on all starts but mine is only on cold starts. so if i were to crank it and let it warm up and shut it off it will not tap anymore. I also have random times where the car will not crank at all, like it will turn over but it will not crank no matter how many times i try it and the only way to get it to crank is to pull the key out and wait a minute and then it will start right up. i havent found anything with other people having the exact same problem i am having.

 

the tapping is most likely you lifters tapping on cold start. as for the cranking issue i would look into you NATS. its the system that gets the signal from your key to start your car. you could have a bad key or a bad antenna.

 

Doesn't the chain have an oil pressure tensioner? Because mine does it for a second on cold start, and it's definitely not the lifters.