engine noise

 a few months ago i lost a door spkr after heavy rain storm,it caused my head unit to gain engine noise,it took a few days to figure out my deck had went bad,,,,,,, now two days ago i lost another spkr(first was drivers door,now passenger door) had to replace wire worked good for 2 days,,now this problem has caused another deck to go bad,have by-passed eq checked all grounds at deck.chassis grounded unit replaced rca cables from deck to eq,replaced spkrs in front and rear doors,, even tried cheating by using ground loop iso which was removin frequencys from music and still having same issues at this point ready to pull everything out and replace all wiring and equipment,any ideas welcomed,have been installing for about 20 years and cant figure this out        HELP !!!!!

What is the car and is there a factory amp/intergration harness being used, are you using the factory speaker wires?Chadillac

91 volvo 740 have by-passed factory amp and yes   using factory spkr wires

Run new 16g wire into doors for start

Unless you have tons of power, do not waste your time running new wires into your doors.  But you may want to perform the test at the top of the following page.  If you still have the last deck, check it too.

http://bcae1.com/images/rca/temporaryrcashieldrepair.html