Fuel pressure

Pressure is not monitored and has nothing to do with when the fuel pump runs. It runs for one second when the ignition switch is turned on, then not again until the engine computer sees engine rotation, (cranking or running). You can sit there all day with the ignition switch on, but the pump will have only run for that initial one second.

You replaced the two least likely parts to cause fuel pressure to bleed down and overlooked the most common cause. That is a leaking injector. To prove the regulator is not leaking, use a hose pinch-off pliers to pinch the rubber fuel return line where it goes from the fuel rail to the steel line on the body. I have never heard of a regulator leaking on a Chrysler product, but if it did, pinching that hose would maintain pressure in the system.

You can also pinch the fuel supply line once the engine is stopped. If that maintains the pressure, suspect the check valve in the pump. I have never run into that. The best way to find a leaking injector is to remove them still attached to the fuel rail. Turn the ignition switch on, then off, then watch to see which injector gets wet on its tip.

The long crank time is due to the battery voltage is drawn down by the starter during cranking, and that lower voltage causes the fuel pump to run slower than normal. Add to that, the injectors are spraying fuel almost as fast as the pump is supplying it. It takes a long time at that rate for the pressure to build up enough to where the engine will run. A trick to overcome that is to turn the ignition switch on, wait a few seconds, turn the switch off, wait about five seconds, turn it on again, and maybe do that a third time, then crank the engine. The pump will have run two or three seconds which is enough to get the fuel pressure high enough for the engine to run.

I would attach a fuel pressure gauge to see if the fuel pressure is that problem. Here is a guide to show you how.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

We could be chasing up the wrong tree. If you don't have a gauge you can rent one for free at the auto parts store.

Please let us know what you find.

Cheers, Ken

Some vehicles have automatic rear height adjusting, and those pumps can be quite noisy. Anti-lock Brake system pumps can usually be heard when the engine is not running, although typically when they need to turn on, they run for 10 to 20 seconds.

It sounds like you have two problems. Fuel pressure should hold for weeks. You're losing pressure very quickly, and your pump isn't running when it should be. First pinch off the fuel return hose where it is rubber between the fuel rail and the body. If the pressure no longer bleeds down, pull out the regulator and look at the smaller rubber o-ring on the tube. I've had two of those that were cut resulting in long crank times. One was on a customer's car and one was on a brand new one in the showroom.

For the dead fuel pump, check if you're also missing spark. Then, check if the automatic shutdown, (ASD) relay is turning on during cranking. The fastest way to do that is to use a test light to measure the voltage that feeds that circuit. Look for the wire that is the same color at every injector, commonly a dark green / orange wire. Back-probe that wire at any injector or the ignition coil. Digital voltmeters don't respond fast enough, so use a test light if you have one. You should see it light up for one second when you turn on the ignition switch. If it does, it must turn on steady during cranking.

I was going to say I think the ECM is bad so its great we came to that conclusion together. I would try to find a used one BTW.

Please let us know what happens so it will help others.

Cheers, Ken

If you know how to identify a broken solder connection, and you find one, look for a local tv repair shop, if there's still one around that wasn't run out of business by the manufacturers. Bad solder connections account for at least half of their repair business. The problem I think you're going to be faced with is these boards are usually sealed in a gel material that is hard to see through. I've ground some of that stuff off to solder on wires and create breaks to build "bugs" for my students to diagnose. Ford computer boards are not sealed against moisture like that, so they're easier to break, but I built mostly Chrysler trainers because they donated a lot of cars to our school when they were done with their dealer training on them.