2003 Mazda Tribute Cold Start Problems

RRU5377

MEMBER
2003 MAZDA TRIBUTE
80,000 MILES

I'm having cold start issues with my 2003 Mazda Tribute ES 2WD but the car runs fine otherwise. The battery is 9 months old and I had it checked recently. It will crank normally but not start on the first try if the fuel tank is less than half and has been sitting for several hours. Starting the car isn't a problem if I pressurize the system first by turning the key to the on position for a few seconds, turning it off for five seconds and then start the car. The fuel pump does make a humming sound for a second or two when the key is in the on position and shows no symptoms of going bad while driving. I replaced the fuel pump relay and had the fuel system flushed and the filter changed with no results. Are there any other issues that can cause a lack of fuel pressure at start up other than the fuel pump itself?

Thanks in advance for your help.

1 Reply

TY ANDERSON

MECHANIC
719 POSTS

To know if you have a fuel pressure issue I would test the fuel pressure on a cold start to see if it is within specifications. Connect a fuel pressure tester, start the engine and check pressure gauge it should be between 55-70psi. Then shut off the engine and observe the fuel pressure gauge after one minute. The pressure should not drop below 5 psi from the pressure measurement when engine was running. If pressure drops suspect fuel injector leaking.

The fuel pressure regulator is built into the fuel pump assembly but I wouldn't suspect that at this point.

Other issues can cause hard starting besides fuel pressure. For example a idle air control valve could be sticking open or fuel vapor purge valve could be sticking open causing a hard start.

Start with the fuel pressure test then let me know from there.