hi , heres mi question, i have a maxima 90 STD SE , when my car is stop with the engine on i hear little explosion on the exhaust,so im planning to diagnose that with a computer but check engine signal isnt on, the mechanic say's that will not diagnose the problem if the signal its off , so any one knows what causes that,(sparks,any sensor etc) (also i have a friend with the same problem (92 SE) ,'

Any way the car runs great, and the engine are in good conditions (no sounds in front the car)

Thanks for your help

Exhaust leak somewhere. Depending where it's coming from, it could be either the exhaust manifold studs(front) or a hole in the exhaust pipe somewhere(bottom of the car to the rear of the car)

backfire??
 

could be plugs, wires, maybe 02 sensor. also I had something wrong with the fuel injector wire harness on my second cylinder a few weeks ago, got it fixed and no more miss/backfire.... :gotme:

explosion?
thats odd
might be an exhaust leak
i know mine shoots flames
which rules
keeps people off my bumper

It might be your Injectors!!! Mine made explosion sounds untill I got my injectors replaced. Now it has gone. Though also it may be your plugs or an exhaust manafold leak around your studs. Can you see the studs still???