No power to injectors in throttle body

You said it does not crank, but it does when you pour gas in? Are we working on a starter problem or a running problem? If the engine is cranking fast enough to start, the starter is working. Have you checked the diagnostic fault codes? Have you checked for spark? Under what conditions are you expecting to find twelve volts at the injectors? What led up to this? Did the problem start after you replaced the fuel lines, or did you replace the lines in an attempt to solve a problem?

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I think you are confusing the issue with your terminology. "Crank" means the starter spins the engine. If the engine runs when you pour gas into it, that means it runs. The next concern is you said you have spark. If that is correct, we are way past looking at the crankshaft position sensor and the camshaft position sensor. Those have to work for the Engine Computer to turn on the automatic shutdown, (ASD) relay. That relay sends current to the ignition coil, injectors, alternator field, and fuel pump or pump relay. The fact you have spark proves the ASD relay is turning on, and it proves there should be twelve volts at the injectors. What a lot of people overlook though is the ASD relay only turns on for one second when you turn on the ignition switch. It turns on again during engine rotation, cranking or running, and the computer knows that by the signal pulses it gets from the two sensors. If you are testing for twelve volts at the injectors, it is best to use a test light because digital voltmeters do not respond fast enough to see that initial one-second pulse. After that, you must be cranking the engine when testing for voltage on that circuit.

Your crankshaft position sensor is in the transmission bell housing, right behind the right cylinder head, but as I mentioned, it has to be working if you have spark. The first thing you must be aware of is if the battery is disconnected or run dead, the Engine Computer loses its memory. Same is true when you disconnected the computer. Chrysler Engine Computers have an extremely low failure rate, so that should be the last thing on your list of suspects. Fuel trim data will be rebuilt as soon as you start driving, but you have to perform a procedure to relearn "minimum throttle". Until you do that, you may need to hold the accelerator pedal down 1/4" for the engine to start. You will not get the nice 'idle flare-up" to 1500 rpm at start-up, and it will tend to stall at stop signs. To meet the conditions for the relearn to take place, drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the pedals.

You are also right that the people at auto parts stores that will read fault codes for you can usually only do that on 1996 and newer models with the on-board diagnostics version 2, (OBD2), emissions system. I am surprised your mechanic does not know that Chrysler makes reading fault codes yourself much easier than any other manufacturer. Cycle the ignition switch from "off" to "run" three times within five seconds, without cranking the engine. Leave it in "run", then count the flashes of the Check Engine light. You will get a single flash for the digit "1", a short pause, then two flashes. That is code 12 and just means the power to the Engine Computer was lost recently. That's because it was unplugged. If there are other codes, they will flash the same way after a longer pause. The last code will be "55" which means "end of message".

Any codes that were in the computer were erased when you unplugged it, so that valuable information was lost. Some codes will not set easily just from cranking the engine. If I had to guess, based on your description of the symptoms, I would be looking at a failing MAP sensor or a cracked vacuum hose going to it. That sensor has the biggest say on fuel metering calculations on Chrysler products. Most other manufacturers have not figured out how to do that. They use the mass air flow sensor instead.

Also, be aware the Chrysler dealer's parts department has repair kits for the fuel filter. You get four fittings, two straight and two curved, four fuel injection hose clamps, and two pieces of hose. You use only the two fittings needed on your truck. If I understand that you moved the filter to under the hood, that is likely to make the hose too short to flex properly when the engine rocks. Heat could be an issue too as it can turn hot fuel to a vapor that cannot be pumped. That is not an issue on your truck because the fuel is constantly flowing through the regulator and back to the tank. The bigger concern is the rubber o-rings in those fittings. When they get cold, they do not flex and stretch well to accommodate the flexing. It is real likely you will find fuel leaking from them until they warm up. Throttle body injection systems run at a pretty low pressure, typically around fourteen pounds, but that is more than enough to spray fuel onto hot exhaust parts.

Check if you have fuel pressure. If you hear the hum of the fuel pump for that first one second, but you do not have any fuel pressure, suspect the two hoses are switched at the tank. I had so many miles on my 1988 Grand Caravan that I had to replace the pick-up screen in the tank twice. Both times I ended up with a crank/no-start because I switched the hoses, and I am supposed to be the expert! If the hoses are switched, you will find fuel spraying from the return hose when you loosen the clamp.

Okay, crank means the engine turns over when you turn the key. Run means it actually starts and runs. Very confusing when you mix them into the issue.

Unplug the upstream O2 sensor and see if your power returns. The symptoms you had earlier suggest the SBEC couldn't control the fuel. The O2 sensor is on the same feed as is the fuel pump. If it was shorted internally it could cause this issue.

Crank sensor is on the top right side of the bell housing/engine flange area. Simple two wire sensor.

You are still overlooking the undeniable fact that you have spark. The cam and crank sensors are working, so leave them alone. The only way to have spark is if twelve volts is being fed to the ignition coil. That twelve volts comes from the ASD relay. The Engine Computer turns that relay on when it gets signals from both sensors, and the engine has to be rotating for them to generate their signals.

Which fuel hose are you getting fuel to spray from, the supply or the return hose?

On most models, if you think you miscounted the flashes, you can just turn the ignition switch off, then back on once, and the codes will start over from the beginning. This test mode will continue each time you turn the ignition switch on until the Engine Computer gets a voltage signal from the starter relay circuit. To say that in normal terms, the codes will stop flashing once you crank the engine, even if that is only for a fraction of a second.

Ford's of this era were known to set multiple identical codes one right after the other, but I have never seen that on Chrysler products like you have here with the two "23"s at the end of the sequence. Double-check those codes, but from what I see here, they are:

12 - Memory to controller has been cleared within 50-100 engine starts.
33 - A/C clutch relay circuit, open or short detected.
11 - Camshaft signal or ignition signal, no reference signal during cranking.
31 - Purge solenoid circuit, open or short detected.
23 - Air charge voltage high/low detected.

Code 11 refers to the distributor pick-up assembly. My gut feeling is most of these codes set when something was unplugged for testing while the ignition switch was on. I do not know how you can have spark if the crankshaft position sensor is missing. Ninety five percent of crank/no-starts are caused by a loss of spark and fuel pump/injector pulses, and those sensors are what is in common with both systems. Loss of spark by itself is responsible for about two percent of those no-starts. Loss of only injector pulses is the cause only about three percent of the time. Since you have spark and fuel pressure, watch for a cone-shaped spray of fuel pulsing from each injector while a helper cranks the engine.

You pulled it off from the throttle body? There should be gas pouring from the port on the throttle body during cranking. If there is not, remove the hose leading into the fuel filter. You should see fuel run out of that hose for the one second when the ignition switch is turned on, and again during cranking.

OK, this truck ran fine until you changed the fuel lines correct? After that it wouldn't run correct? What fuel pressure are you getting at the throttle body? It takes a minimum pressure for them to work, as you are getting nothing in the return line I would suspect you are not getting the correct pressure to open the regulator.