I've posted awhile back about half white half black spark plugs. All 4 had the same pattern. Since then I've changed my fuel filter and a week later check out my spark plugs again. This time when looking at the plugs from under the car, the right side is leading=pure black, trailing = black in the middle and white on the outside. Left side is leading=black inside white outside, trailing=black inside white outside. My question is is the primary or secondary fuel injector for the left side or right side? This is when your looking at the plugs from under the car. Is the process of taking out the injectors hard? How can I test the fuel pressure?

 

Liemoanh,


You have 1 pri and 1 sec injector for the front housing and the same for the rear.

They are somewhat difficult to get out. The upper intake manifold (UIM) needs to come off and various other stuff. If you don't have the shop manual go to the Mazda dealer and order one (make sure it's the small manual). This will help you greatly.

To test the fuel pressure...go to auto parts store and get fuel pressure tester, and some small hose clamps.

Beside the oil filter you will see three black hoses..one to bring fuel to the fuel rail, one for the charcoal canister, and one to take fuel back to the tank. The second hose from the firewall is from the fuel filter going to the injectors...this is the hose you put the pressure tester on.


Later, Scott

 

what kind of pressure am I looking for? what is a good reading? Do I need to take off anything to gain access to these fuel hoses? Thank you