markdman

its a base model and all that...

the question i have is when i got to start up this car im thinking about buying, its takes a little while to actually start, then when it does there is a very loud pop from the engine bay. after it warms up, it idles fine. it does this every time the car starts. will it need a new motor?

MazdaMike02

iTrader: (4)

Sounds like backfire, does it have an aftermarket exhaust system? Or is there a leak in the system?

Whats the compression look like? Its probably backfiring due to an excess of fuel in the exhaust manifold. This can be caused by improperly burnt fuel mixture, low compression, or maybe its running on one rotor?

I would check the compression, do so with a piston tester (if you have to). Theres a few ways to do it, but i've always been told to take the shrader valve out of the bottom with a valve core tool. Have an assistant crank while you watch for 3 even bounces. You should also put some oil in the spark plug holes. Now you want at least 30 psi each bounce. That would give you 90 psi per rotor, apparantly 85 is the lowest but if you see that don't even bother its gonna need a rebuild soon. 90 psi is enough to have starting issues, I know my 7 has 90 psi on the front rotor and it doesn't start as fast and it can flood if I'm not careful.