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I have issue with my toyota and I have done almost everyting and we cant figured out that is the problem with that one cylider misfire p0304.
What I have done so far is:
- Changed all sparkplugs twice first bosch and later NGK
- New coil bosch and I have tried with other cylinder coils. Spark is strong and bright when the plug is in the coil, out of the cylinder
- I have tested and measured all 4 coil wires and every one of them in all cylinder gives same result. Continuity to ECM tested
- O2 sensor (oe-quality) tested and I have tried with new one on block 1. Car gave me some point p0172 code which is rich mixture code. That code havent come again.
- I have changed fuel injectors from other cylinder to cylinder number 4 but problem doesnt follow
- fuel injector wiring tested and all gives same ohms 14.2 and continuity to ecm tested. Grond is also good
- Fuel pressure is 3.2bar/46psi
- compression test good about 160psi all cylinders
- leakage test ok all cylinders
- cam sensor test gave me AC 0.8-1v. ohms 1150. Continuity to ECM tested
- New airfilter
- With new MAF-sensor tested. No effect
- Intake leak tested with break cleaner. No effect to running
With bosch obd reader I have noticed that misfiring goes in cycles. Misfires rices from 0 to 100 and back to 0 and again to 100. If I pull cam sensor pug out its stays on 10 misfires.
Misfire occur all the time. If I unplug the coil wiring car to running in any cylinder. If I unplug fuel injector wiring nothing happens at cylinder 4. For other cylinder I notice difference. Spark plug gets wet if coil is out and plug in the cylinder. So its getting fuel. Also I hear clickin noise for all cylinders.
Freeze frame data shows misfires cylinder 4. Also noticed air fuel mixture is richer at o2 sensor bank 1.
If the ecm provides injector pulse and spark for the missing cylinder I wouldn't be too concerned about it at this point. At this point you may want to take running compression readings, at idle and snap throttle, one on a good cylinder and one on the offending one. If you had an oscilloscope you could do other, quicker measurements though.
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Last edit: 3 years 7 months ago by juergen.scholl.
I am started to be desperate now. Comperssion seems to be good and second leak test was same than before. I also cheaked timing and that was also good.
I double cheaked continuity to ECM from coil, fuel injector and cam sensor. Everyting was good. Also tried with other crankshaft sensor and also no effect on that one....
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