We recently had a customer come in with a 2016 Dodge Challenger with a flashing check engine light. We scanned the car and got the codes;
- p0128 Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature
- p0205 Cylinder 5 Injector “A” Circuit
- p0305 Cylinder 5 Misfire Detected
- p0300 Random/Multiple Cylinder Misfire Detected
Why Engine Misfires Happen
Engine misfires happen when either AIR, FUEL, or SPARK as insufficient for the combustion process in each cylinder.
We can check for air by checking the Engine Air Filter and making sure it isn’t clogged or checking for any debris or blockage in the air intake system that delivers filtered air necessary for combustion into each cylinder.
Spark issues can be cause by bad spark plugs or ignition wires. So we can removed them and inspect them for damage.
Fuel issues can be cause by a bad fuel pump or bad injectors.
Diagnosing the Misfire
We saw that the misfire detected was predominantly on cylinder #5 and that the Cylinder #5 injector had a circuit fault.
Injectors can be tested by measuring the resistance reading they give on a multimeter. So you can disconnect the injector from the wiring harness and with a multimeter set to Ohms or the Ω symbol. Choose the lowest range available on the multimeter as the resistance reading should be around 15 to 20 depending on the car. We measured the resistance on each injector seeing that it is within range. in this particular Dodge challenger the reading should be around 18 Ohms.
When checking the cylinder #5 injector we saw that is gave a reading that was way off. It was reading about 2.3 Ohms. That confirmed that indeed the injector was faulty!
We were able to replace the faulty injector and the misfire was gone!
If you have a Domestic, Asian, or European vehicle in need of diagnostic or maintenance feel free to Contact Us @ Tolima’s Auto Center!
