Testing a 'no-start no-spark' or misfire condition on your 2.4L (SOHC) Mitsubishi (Chrysler Sebring or Dodge Stratus) is not hard at all and this article will show how to in easy to follow step by step instructions.
Also, to use the info in this tutorial you don't need a scan tool!
NOTE: This article covers the Coil-On-Plug (C.O.P.) ignition coil and crankshaft position (CKP) sensor test on the 2.4L Single Overhead Cam (SOHC) engine and the 1.8L Mitsubishi engine. To see if this tutorial applies to your specific vehicle, take a look at the Applies To: box on the right column.
You can find this tutorial in Spanish here: Cómo Probar La Bobina De Encendido Y El Sensor De La Posición Del Cigüeñal (2.4L Mitsubishi) (at: autotecnico-online.com).
Symptoms Of A Bad Ignition Coil / Bad Crank Sensor
When one or several ignition coils on your Mitsubishi (or Chrysler Sebring or Dodge Stratus) have gone bad, you'll know right away. Your vehicle will display one of the following symptoms:
- The car will run and idle rough.
- No power as you accelerate the car down the road.
- Really bad gas mileage.
- The vehicle will not start.
- The car will not run on all cylinders.
- Misfire codes that are lighting up the check engine light (CEL) on your instrument cluster.
- P0300, P0301, P0302, P0303, P0304.
- Rotten egg smell coming out of the tail-pipe.
When the crankshaft position sensor goes bad on your Mitsubishi vehicle, the car will crank but NOT start. Usually this will cause a no-spark condition on all of the cylinders.
What Tools Do I Need?
Testing the Coil-On-Plug (COP) ignition coils on your Mitsubishi vehicle (or Chrysler Sebring or Dodge Stratus) doesn't require any expensive testing equipment or expensive tools. As mentioned at the beginning of the article, you don't need a scan tool.
Now, you do need some very specific tools and below is the list of them that you'll need to successfully troubleshoot and diagnose a bad C.O.P ignition coil on your Mitsubishi car:
- A 12 Volt test light.
- A multimeter that can read Hz frequency.
- Without a multimeter that can read Hertz frequency, you won't be able to accomplish some of these tests. (don't have a digital multimeter that can read Hertz frequency? Click here to see my recommendations: Buying A Digital Multimeter For Automotive Diagnostic Testing).
- An HEI spark tester
- This tool is a MUST have to be able to successfully diagnose (without complications) your Mitsubishi vehicle (or Chrysler Sebring or Dodge Stratus) with the tests presented in this article (don't have an HEI spark tester? Need to buy one? You can buy it here: OTC 6589 Electronic Ignition Spark Tester).
- Battery jump start cables.
- Someone to help you crank the car.
Circuit Descriptions Of The Ignition Coil Connector
Each ignition coil has three wires coming out of their connector. Each one has a specific function and below, you'll find out what they are. This will be the info you'll need to perform the tests in this article:
- Circuit labeled 1:
- 12 Volts
- Circuit labeled 2:
- Circuit labeled 3:
- Triggering Signal Circuit.
The color of the wires is not important (to take advantage of the info in this article) as long as you're able to correctly identify the circuit by its number in the photos supplied.
Circuit Descriptions Of The Crankshaft Position Sensor
The crankshaft position sensor on your Mitsubishi car is a three wire Hall Effect type sensor that can be easily tested with a multimeter. Below are the circuit descriptions that you'll need in the tests presented in this article:
- Circuit labeled 1:
- Crankshaft position (CKP) sensor signal. CKP signal output to the PCM.
- Circuit labeled 2:
- Power circuit (12 Volts).
- Circuit labeled 3:
- Ground circuit (provided by PCM).
The crankshaft position (CKP) sensor on your Mitsubishi Car (or Chrysler Sebring or Dodge Stratus) is located behind the timing belt but testing it is done without removing the timing belt or its components. In the photo you can see that its connector is located pretty much in plain sight and with plenty of access to test it.
Basic Operating Theory
This type of ignition system does not use an external ignition control module (ICM) but a transistor inside each of the two ignition coils. The fuel injection computer triggers these transistors to activate the ignition coil that they are a part of. Now, when the ignition coil is activated to spark, it feeds spark to two engine cylinders at the exact same time.
So then, in a nutshell, when you turn the key to crank and start the car, this is what happens:
- The engine starts to crank, inducing the crankshaft position sensor to start producing its crank signal.
- The crank signal upon being received by the PCM along with other necessary sensor information, starts to do its little song and dance and sends back a Triggering signal to each ignition coil.
- This Triggering signal contains the instructions for the transistor (within each ignition coil) to start firing the ignition coil it's a part of.
- Each Coil-On-Plug (COP) ignition coil then fires spark to two different cylinders at the exact same time (in what's known as the Waste Spark method).
- One cylinder is fed spark directly by the ignition coil.
- The other cylinder is fed spark thru' a spark plug wire (high tension wire).
OK, technically speaking, this type of ignition system is not a true Coil-On-Plug (C.O.P.) system but hey, if it kinda' looks like a duck and kinda' quacks like a duck who cares? You're here to test them, not hold a debate about what category of ignition system they fit into.
Precautions, Do's And Don'ts
Most of the testing that you'll be doing is with the engine cranking so take all necessary safety precautions to keep your fingers, hands and entire self safe. Here are a few other tips and suggestions:
- Don't use a regular spark plug instead of a spark tester to test for spark. Using a regular spark plug will give a false test result that'll have you chasing the wrong diagnostic path/conclusion and in the process wasting time and money.
- Do not remove the spark plug wire from the spark plug or the ignition coil while the engine is cranking to test for spark. This method will ruin the ignition coil. Remember, you're here to solve a problem, not create another one.
- Start your diagnostic from TEST 1, do not skip around from test to test unless instructed to do so by the TEST you are currently on.
- Do not use a test light where an LED light is called for.
- The color of the spark jumping across the HEI spark tester is immaterial to out tests. In other words: the color of the spark does not matter. I'm sure you've read that a blue spark is a strong spark and a yellow spark is a weak spark. THIS IS ALL BALONEY.
- Once again, use the recommended/indicated tools for all of your tests.