Engine cranks but will not start

Why would you not include all the fault codes? Code 403 refers to the EGR system. That will not cause a failure to start or run. You also have an engine running problem but you did not bother to list which engine you have. You need to provide some information or test results to analyze. Do you even know if it is fuel, spark, or both that are missing? I am assuming the starter cranks the engine, but if it does not, people also call that a "no-start".

Dandy. You have a 3.0L engine. I thought there was another V-6 available, but I see that is not the case for this model.

P0128 - ECT Below Thermostat Regulating Temperature
P0153 - Oxygen Sensor Circuit Slow Response (Bank 2 Sensor 1)
P0340 - Camshaft Position Sensor Circuit Malfunction
P0403 - Exhaust Gas Recirculation Circuit Malfunction
P0421 - Warm Up Catalyst Efficiency Below Threshold (Bank 1)
P0431 - Warm Up Catalyst Efficiency Below Threshold (Bank 2)
P0456 - EVAP Leak Monitor Small Leak Detected

Code 456 will usually require the use of a smoke machine because small leaks are almost impossible to find any other way.

Without digging further, code 403 is not specific enough to know where to start. This could refer to a failed sensor or its wiring for the sensor on the EGR valve. It could also refer to incorrect gas flow is seen when the valve is opened. Regardless, these two codes will not cause a no-start.

Codes 153, 421, and 431 could potentially all be related to code 128, so start with code 128. Suspect the thermostat is stuck open. If it is, you won't get nice hot air from the heater. The engine computer calculates fuel needs based on multiple engine sensors, including the engine coolant temperature, (code 128). When a specific temperature is reached, the system switches to "closed loop", meaning the computer adds the front oxygen sensors' readings to the list of variables to fine tune the fuel metering calculations. If the coolant is not getting up to normal operating temperature, the computer may not look at the O2 sensor readings. Codes 421 and 431 are derived from readings from the two rear oxygen sensors. The computer may be confused because what it expects to see is not taking place in the catalytic converters because they are not getting hot enough to do their thing.

The problem with my guessing is to set any diagnostic fault code, there is always a long list of conditions that must be met, and one of those conditions is certain other codes cannot already be set. That is because the computer is constantly comparing numerous sensor readings and operating conditions to each other to figure out when one is wrong. If a code is set for a sensor reading, any test that needs that reading to be compared to will be suspended. With some tests suspended, defects will not be detected and codes related to them will not be set. To say that a different way, when multiple codes are set, you must consider the possibility they all refer to individual, unrelated problems. The best approach is to start with anything that looks like it might be causing all the problems, fix that problem first, erase the fault codes, then see which codes set again, and start from scratch.

Code 340 is the one you need to start with. Listen for the hum of the fuel pump for one second after turning on the ignition switch. If you hear that, the automatic shutdown, (ASD), relay is working and the engine computer has control of it. That relay sends current to the ignition coil, injectors, oxygen sensor heaters, and fuel pump or pump relay. At issue is that relay turns on again during engine rotation, (cranking or running), and the computer knows that by the signal pulses it receives from the crankshaft position sensor and the camshaft position sensor. You have a code for the camshaft position sensor circuit, but a missing signal from either sensor will prevent the ASD relay from being turned on, and you will have no spark and no injector pulses.

By far most crank / no-starts are caused by loss of spark and fuel. Less than about five percent are caused by loss of spark or fuel. The fact you smell gas suggests you have only a loss of spark, but that would not agree with code 340. Assuming you do not have a scanner to view live data, the best approach is to replace the cam sensor. It is important to understand that fault codes never say to replace parts or that one is bad. When a part is referenced in a code, as in code 340 here, that part is actually the cause of that code about half of the time First we rule out wiring and connector terminal problems before we order a sensor, but in this case, the sensor costs a lot less than paying for an hour of diagnostic time. If you are wrong, you can save the part for later. If you are right, you will have saved a bundle.

Nope. Coolant is coolant when it comes to transferring heat from the engine to the heater core in the dash. Water actually holds more BTUs of heat than does antifreeze, so it is more effective at moving heat to the heater and to the radiator. The problem is the coolant will do severe damage to the engine, radiator, heater core, and hoses if it freezes. That is one reason we need to add some antifreeze. The other reason is antifreeze has additives in it that prevents corrosion and lubricates the water pump bearings and seals.

As long as the coolant is not frozen, it is going to transfer heat away from the engine. If it does that too well, before it has reached about 195 degrees, it is due to the thermostat opening too soon, or it is stuck open. It needs to remain closed until the desired temperature is reached, then it will open and let coolant flow to the radiator. Some engine parts are purposely shaped incorrectly, and will develop excessive wear because of that, because they expand to fit properly when they reach proper operating temperature. That is why almost all engine wear takes place in the few minutes the engine is warming up, and almost no wear takes place during extended highway driving. So besides needing the thermostat to work right to get good heat from the heater, it needs to work right to reduce engine wear and for the fuel mileage to be its best and emissions to be its lowest.

Once you get the no-start solved, work on the low coolant temperature problem. If solving that solves the other issues, you are ahead of the game. If the other fault codes still come back, you have not lost anything. Now you are operating in our world where it can be impossible to give you an accurate estimate for repairs.

First lets clear up some terminology so we're both talking about the same things. "Would not crank at all" is a starter problem. The spark plugs and fuel filter aren't even in the picture yet. If the starter is cranking the engine, you have most likely had the same problem all along but you replaced the wrong parts. The place to start is by reading the diagnostic fault codes. Mitsubishi and Chrysler have a lot of things in common but I don't know if reading codes is one of them. With Chryslers, cycle the ignition switch from "off" to "run" three times within five seconds, leave it in "run", then count the flashes of the Check Engine light. You'll get from one to five flashes for the first digit, a short pause, then a series of flashes for the second digit. After a longer pause the next code will flash the same way if there is one.

The most common failure is the camshaft position sensor. The Engine Computer needs to see pulses from it and the crankshaft position sensor, then it knows the engine is rotating, (cranking or running). When it sees engine rotation, it turns on the automatic shutdown (ASD) relay. That relay sends current to the ignition coil, injectors, and fuel pump or pump relay.

Both of these sensors commonly start to fail by becoming heat-sensitive. They will either stop working after the engine has warmed up, resulting in stalling, or they'll fail right after a hot engine is turned off and that heat migrates up to them. You'll have a "cranks / no-start" condition, but it will work again once it cools down for an hour.

To verify the rest of the ASD relay circuit is working, monitor the voltage at the ignition coil or any injector with a test light. A voltmeter will work too but some don't respond fast enough to be accurate. You will see the test light light up for one second after turning on the ignition switch. That tells you the circuit is working and the computer has control over the relay. The test light should turn on again during engine cranking. If it does, and it stays on steady, you have a fuel pump OR a spark problem. Both are relatively rare. Most commonly the light will not turn on during cranking. That's when you look at those two sensors.

Both the camshaft and crankshaft position sensors are supplied with 8.0 volts on their yellow wires. That's terminal # 1 on both connectors.

Ground wires appear to be black with a green stripe, (B-G), (I have a hard time with Mitsubishi wiring diagrams). They should have close to 0.2 volts. That's terminal # 2.

Terminal # 3, (L-W) is the crankshaft sensor's signal wire. Voltage should pulse between 0 and 5.0 volts during engine cranking.

The camshaft sensor's signal wire is "L-R". No idea what color "L" is.

If either sensor is unplugged, its signal wire should go to 5.0 volts.

If you find the 8.0 volt supply missing to only one sensor, suspect a broken wire, commonly at the splice. If it's missing at both sensors, there could still be a broken common feed wire, or that circuit could be shorted to ground. If a short is located and removed, the ignition switch must be turned off and back on for the 8.0 volts to come back. When that line is shorted, the Engine Computer shuts the supply down to protect it. It won't turn back on until the ignition switch is cycled.

A shorted 8.0 volt line can also be determined with an ohm meter, but the ignition switch must be turned off.

Caradiodoc

Nope, when you're working with the coils, you're in a different circuit. Voltage for the coil(s), injectors, alternator field, and fuel pump or pump relay comes through the Automatic Shutdown (ASD) relay. The Engine Computer turns the relay on when it gets pulses from the cam and crank sensors. So, check for voltage at the coil while a helper is cranking the engine.

Caradiodoc

Forget about the coils. In a previous test, you said there was no voltage to them during cranking. If that is still correct, the Automatic Shutdown (ASD) relay isn't turning on. That will be related to the crankshaft position sensor or the camshaft position sensor. If those signals are missing, the Engine Computer turns the ASD relay off and there will be no voltage to the coils, injectors, alternator field, and fuel pump.

Caradiodoc

If you have two individual coils, try switching them, then see if the same coil fires. If they are both in one assembly, try switching the two control wires, then see if the other coil fires. That will tell if it's the coil or the control wire.

This symptom sounds very much like what can happen with a Dodge Neon with the single overhead camshaft. The dowel pin between the camshaft and sprocket breaks, and the sprocket turns on the cam a little. That can be just enough to partially shut the system down to where only one of the two coils fire.

Caradiodoc

The pin for the cam sprocket is not something you would have caused. Hope I didn't leave you with that impression. That only applies to the single cam engines.

Happy to hear you have spark now. Injectors out of order would still allow the engine to run. Fuel would still get into the engine. Check for fuel pressure. The pump might not run unless the engine is being cranked. Look for a fuel pump relay. You can bypass it with a piece of wire or by removing the cover and squeezing the contact. If the pump runs this way, but not during cranking, look again to the cam and crank position sensors. You may need to measure on their wires for the voltages.

If the pump does run during crankiong, wait a minute, then measure fuel pressure to see if it is bleeding down.

Caradiodoc