2006 Scion xB P304 Misfire.
07-24-2017, 09:02 PM
#1
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Join Date: Jul 2006
Location: WI
Posts: 7
2006 Scion xB P304 Misfire.
So. I have been having idle problems. Mileage problems and that troublesome P304 (#4 cyl Misfire). My Car has 83,000 miles.
I was getting about 27 mpg. Rough idle and cooling problems as the cooling fan was constantly cycling.
And just recently when starting the car in the cool mornings and turning on A/C or heat I would smell gasoline. I just
figured the wind was blowing exhaust fumes into the car.
So I just bought the BlueDriver OBD2 meter. This thing is so awesome. Way better than my old OBD2 meter. Anyway. I got the BlueDriver and plugged it in and it was saying P304.
The Phone/iPad software tells you the Code and gives you a checklist for possible fixes.
I checked: the plugs. They were slightly fouled. Cleaned them and rechecked. Same. Checked the coils. All good. I used a long Screwdriver and held the tip on the injector when the car was running and I could hear the injectors clicking normally, so it was not a bad injector. I was starting to think maybe the rings were bad and I was going to check compression and pray it wasn't a cylinder problem.
Cylinder #4 had the Misfire. Cylinder 3 was actually leaking fuel onto the manifold right past the top Injector "O" Ring. Injector #3 was shiny. Fuel was pooling in the #3 area and evaporating into the blower and that was the smell.
With the decreased fuel pressure because of the fuel pressure leak on #3, Cylinder 4 and most likely the other cylinders were not getting the correct fuel pressure. I ran a live session while driving before and after showing many parameters and the after test drive showed pressure stabilized. After replacing all 4 injector rubber "o" rings and cleaning(topically) and reinstalling the injectors. ALL of the error codes cleared including the intermittent vacuum issues. I did check for vacuum leaks with starter fluid. No RPM increases.
So so if you are having misfires check and replace the injector O Rings top and bottom.
O'Reilly Part # 274823 $10.99 each. I purchased 4. Cheap fix to an ongoing problem. The engine is running SO much better now. I can't wait to burn through a tank and see the new mileage.
#P304
I was getting about 27 mpg. Rough idle and cooling problems as the cooling fan was constantly cycling.
And just recently when starting the car in the cool mornings and turning on A/C or heat I would smell gasoline. I just
figured the wind was blowing exhaust fumes into the car.
So I just bought the BlueDriver OBD2 meter. This thing is so awesome. Way better than my old OBD2 meter. Anyway. I got the BlueDriver and plugged it in and it was saying P304.
The Phone/iPad software tells you the Code and gives you a checklist for possible fixes.
I checked: the plugs. They were slightly fouled. Cleaned them and rechecked. Same. Checked the coils. All good. I used a long Screwdriver and held the tip on the injector when the car was running and I could hear the injectors clicking normally, so it was not a bad injector. I was starting to think maybe the rings were bad and I was going to check compression and pray it wasn't a cylinder problem.
Cylinder #4 had the Misfire. Cylinder 3 was actually leaking fuel onto the manifold right past the top Injector "O" Ring. Injector #3 was shiny. Fuel was pooling in the #3 area and evaporating into the blower and that was the smell.
With the decreased fuel pressure because of the fuel pressure leak on #3, Cylinder 4 and most likely the other cylinders were not getting the correct fuel pressure. I ran a live session while driving before and after showing many parameters and the after test drive showed pressure stabilized. After replacing all 4 injector rubber "o" rings and cleaning(topically) and reinstalling the injectors. ALL of the error codes cleared including the intermittent vacuum issues. I did check for vacuum leaks with starter fluid. No RPM increases.
So so if you are having misfires check and replace the injector O Rings top and bottom.
O'Reilly Part # 274823 $10.99 each. I purchased 4. Cheap fix to an ongoing problem. The engine is running SO much better now. I can't wait to burn through a tank and see the new mileage.
#P304
Last edited by MR_LUV; 09-21-2017 at 06:05 AM. Reason: Added part number
