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Drew
Drew, Super Mazda Tech.
Category: Mazda
Satisfied Customers: 2518
Experience:  19 yrs. experience. Mazda Senior Certified Tech, with Ford, Linc. & Merc. experience. ASE L1 Advanced Certified Master Tech.
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mazda b2300: a 2003 mazda b2300 came in today with a bad misfire

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a 2003 mazda b2300 came in today with a bad misfire with codes p0316, p0300, and p2195 if i remember correctly. we replaced the coil, plugs, wires. still ran the same. found leak at intake manifold, repaired that, still same results. no other leaks found. what am i missing?
Welcome to Just Answer. My name is XXXXX XXXXX I will be glad to assist you.

Low fuel pressure is very common cause for this concern on these vehicles that I see all the time.

Check fuel filter, fuel pump pressure at the engine. Make sure the fuel pressure regulator is not leaking.

Also check to see if you can verify which cylinder is misfiring. Make sure all compression is good.

Make sure the EGR valve is not sticking open slightly.

Please let me know if you have any additional questions by hitting the reply button.

Thanks
Drew

PINPOINT TEST 11

FUEL LINE PRESSURE / FUEL PRESSURE HOLD INSPECTION

STEP

INSPECTION

ACTION

1

CHECK FUEL PRESSURE

WARNING:

Before performing the following operation, release the fuel pressure from the fuel system to reduce the possibility of injury or fire.See
  • Install Fuel Pressure Gauge SST 49 UN01 010.

  • Key ON, Engine OFF (KOEO).

  • Connect NGS Tester to the DLC and select Active Command Mode.

  • Select OUTPUT TEST MODE.

  • Press MODE to change to the "ALL ON" mode, and press start to run fuel pump.

  • Turn relay off.

  • Observe fuel pressure.

  • Is fuel pressure between 414-448 kPa (60-65 psi)?

Yes

Go to step 2.

No

Zero or low pressure:

Check fuel pump.

If as specified, check fuel line and/or fuel filter for clog or restriction.

Pressure high:

See ,step 2.

2

CHECK FUEL PRESSURE AFTER ONE MINUTE

  • Observe fuel pressure after 1 minute.

  • Is fuel pressure within 34 kPa (5 psi) of previous reading?

Yes

Fuel pressure hold inspection OK.

No

Check the following:

  • Injector fuel leakage.

     

Drew and 6 other Mazda Specialists are ready to help you
Customer: replied 3 years ago.

thank you Drew, I will do that in the morning when I get to work.


 


Chris

Sounds good Chris.

Let me know what you find.

Thanks
Drew

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