No Start

You have already done the first two thirds of the testing. Simply hearing the fuel pump run for one second, and finding twelve volts at the ignition coil for that one second confirms the ASD relay is turning on. What you need to double-check is whether it turns on again during engine rotation, in this case meaning cranking. A test light works best for this but you can do it with a voltmeter too. Go to the wire that is the same color at every injector and the ignition coil, or to either of the smaller terminals on the back of the alternator. If you see the twelve volts come back solidly during cranking, you have low fuel pressure, or no spark, but not both. If that twelve volts does not come back, you will have no spark, no injector pulses, and no fuel pump. That is the cause of about ninety five percent of crank/no-starts.

ASD relay not turning back on is caused by the engine computer not seeing a signal pulse from the crankshaft position sensor or the camshaft position sensor. The crank sensor is the worst culprit on other models because it has a critical air gap that must be set with a paper spacer. Yours is not adjustable. Your camshaft position sensor is of the same design that had a real high failure rate on the 2.2/2.5L engines.

Since you replaced those two sensors already, the next step is to connect a scanner so you can see what the engine computer is seeing. Look at those two sensors to see if they are listed with a "no" or "present" during cranking. If one signal is not showing up, suspect that sensor and its signal wire. If both signals are not showing up, the better suspect is the 5.0-volt feed wire going to them. They also have their ground return wires in common, but that is shared by some of the other sensors too. Look at the voltage readings for the throttle position sensor and coolant temperature sensor. I doubt you have a ground wire problem because that would cause the sensors' readings to go to 5.0 volts, and that would set multiple fault codes.

Do not worry about the missing voltage on the oxygen sensor fuse. That is fed from the ASD relay too and will be there when the engine is running.

Hold on. Lets be sure I'm clear on what you found. Did you use a test light at the ignition coil? As I recall, that should be a dark green / orange wire. You'll find the same color wire at every injector. A test light works best because digital voltmeters respond too slowly.

You should see the test light turn on brightly for one second when you turn on the ignition switch, then it will turn off. This corresponds to the time you hear the fuel pump running. This part of the test confirms the automatic shutdown, (ASD) relay is working, the Engine Computer has control of it, and the associated wiring is okay.

The important part of the test is the light must turn on solidly during cranking. This is where 95 percent of problems show up. The Engine Computer needs to see steady signal pulses from the crankshaft position sensor and the camshaft position sensor to know the engine is rotating, then it turns the ASD relay on to power up the ignition coil, injectors, alternator field, oxygen sensor heaters, and fuel pump or pump relay.

If the test light is bright during cranking, those two sensors are working and the computer is trying to fire the injectors and ignition coil. We know the fuel pump is okay since you heard it run, but if the anti-theft system has been triggered, it stops the pump from continuing to run. The symptom will be the engine runs for about two seconds until the fuel pressure in the system is depleted. This is the time to check for spark, fuel pressure, and injector pulses to see which one is missing. These three systems individually account for a total of about 5 percent of crank / no-starts.

95 percent of these no-starts are caused by a missing sensor signal. The Engine Computer can set a diagnostic fault code to indicate which signal is missing, but that often doesn't happen just from cranking the engine. They are more likely to set while a stalled engine is coasting to a stop. If the battery is disconnected or run dead, those fault codes are erased.

Chrysler made reading diagnostic fault codes in the Engine Computer much easier than any other manufacturer. Cycle the ignition switch from "off" to "run" three times within five seconds, leave it in "run", then watch the code numbers show up in the odometer display. You can go here to see what they mean:

https://www.2carpros.com/trouble_codes/obd2

or you can list them here and I'll interpret them for you. It's important to understand fault codes never say to replace a part or that one is bad. They only indicate the circuit or system that needs further diagnosis, or the unacceptable operating condition. When a part is referenced in a fault code, it is actually the cause of that code only about half of the time. First we have to look for wiring and connector terminal problems, and mechanical problems associated with that part.

It's when there is no fault code to direct you to a circuit that we need to view live data on a scanner. I have a Chrysler DRB3 scanner for all of my vehicles. That shows the cam and crank sensors with a "No" or "Present" but most other scanners have a similar way to show that. As I mentioned earlier, it isn't likely two sensors failed at the same time, so if both signals are missing, a cut wire common to both sensors is the better suspect. When either sensor is providing a good signal, we know all the wiring both sensors have in common has to be okay.

If the crankshaft position sensor's signal is missing, verify it is fully-seated. The air gap on older versions
of this sensor was adjustable, and was critical. Yours needs no adjustment, but if the mounting bracket is bent and the sensor sits up too high, the magnetic field won't generate the signal. If it sits in too deeply, it will be hit by the flex plate and will be broken.

If the camshaft position sensor signal is missing, double-check the shutter wheel / vane assembly is in place under the sensor disc. Verify the distributor shaft is rotating.

There's one more thing to be aware of before you get too "wrapped around the axle". If the battery was disconnected, idle speed will be too low, possibly to the point of the engine not starting. That has a real simple solution, but for now, to identify that, just hold the accelerator pedal down 1/4 during cranking.

One of those two signals is missing during cranking.

The two sensors share a common ground with other sensors, and that circuit goes through the Engine Computer, THEN to ground. That way the computer can monitor that circuit. There will be four ground wires on the computer. Two for high-current pulsing items like injectors and ignition coil(s), and two for sensitive circuits like sensors. You'd have a whole pile of diagnostic fault codes for multiple sensor circuits if both signal ground wires were broken.

As a place to start, remove the automatic shutdown, (ASD) relay. If you do that while the engine is running, it had better turn off as that is what feeds the ignition coil and injectors. If you remove it after the ignition switch is turned off, pay attention to feel if that relay clicks when it is pulled out. Leave that relay out until you're ready to use the truck again. After that, we'll need a digital volt / ohm / amp meter to do some testing for a battery drain. If you don't have one already, Harbor Freight Tools has a perfectly fine one for under ten bucks. A pair of small jumper wires will be helpful too.