Hard starting, runs fine

If I read that right, you have a long crank time, but once the engine starts, it keeps on running okay. Stop me if I have that wrong. This is the typical symptom for fuel pressure dropping when the engine is stopped. It should hold for weeks, but for sure at least overnight.

You should hear the fuel pump run for one second when the ignition switch is turned to "run". That is to insure fuel pressure is up for starting in case it dropped a little. That one second is not long enough if the pressure dropped real far or to zero. The pump doesn't resume running until the Engine Computer sees engine rotation, (cranking or running). That means if fuel pressure had dropped a lot, it can take some time for it to build back up to where the engine will run, and to add to the misery, battery voltage is drawn down to as low as ten volts during cranking. That means the fuel pump will be running considerably slower than normal at that time. Fuel pressure builds too slowly, and some will be bled off by the injectors trying to fire.

There's two ways to verify this. The proper way is to connect a fuel pressure gauge and watch what happens when the engine is stopped. I circled the fuel pressure test port in the drawing below. The second way to get a clue is to cycle the ignition switch multiple times before cranking the engine. The pump will run for one second the first time the ignition switch is turned to "run". Turn it off, then back to "run" a second time, and perhaps a third time, then crank the engine. The pump will have run longer and built more pressure. The engine will start quicker if fuel pressure is the problem. I don't recommend cycling the ignition switch more than three times. On some models, the cranking system will be locked out after three attempts, then you have to wait a minute or more before resuming. That can let the pressure bleed off again.

If you verify we're on the right track, there's four places fuel pressure can bleed down. The least common is through the check valve in the fuel pump. To find that, use a hose pinch-off pliers to block the supply hose where it transitions from the body to the engine. That will maintain pressure at the test port while it drops on the tank side of the pliers.

Another place is through a leaking fuel pressure regulator. This doesn't apply to your engine, but for those older models where the regulator is on the fuel rail, excess fuel passes through the spring-loaded regulator, then back into the tank. Use the hose pinch-off pliers to block that smaller return line. If the regulator is leaking, fuel can't get past the pliers to bleed down, so pressure will stay up. That style regulator is shown in the second drawing.

The third place also doesn't apply to your truck, but for the benefit of others researching this topic, it's the rubber o-ring with the red arrow in the second drawing. I've been involved with two of these, one on a brand-new car just delivered to the dealership, and one on a high mileage model. The owner refused to buy the 25-cent o-ring so we had to let the car go that way. Both had a very long crank time, but the engines ran fine once started.

The clue to a leaking o-ring is when the engine is stopped, fuel pressure drops to "0" within a few seconds. If the regulator's valve is leaking, it will take longer for pressure to drop; perhaps as long as two or three minutes. The two o-rings I found were cut. That's an issue with the person who installed those regulators. It's not something that develops on its own over time.

The third drawing is for your 2003 model. It shows the newer-style pressure regulator back at the tank. I haven't heard yet of someone solving a problem by replacing that type.

Probably the most common cause of dropping fuel pressure is a leaking injector. The clue is with the pinched-off fuel supply hose, (and the return hose on older models that have the pressure regulator on the fuel rail), you will still lose pressure at the test port. With both lines blocked, if fuel pressure drops off, it can only be past an injector or one of their o-rings in the fuel rail. If one of those o-rings is leaking, you'll smell and possibly see the gas seeping out. You're also likely to smell it inside the vehicle. You won't see or smell it if it's leaking from the injector's valve. To identify that, you have to remove the fuel rail with the injectors still attached, then look at each one to see if any are wet. The clue to a leaking injector is it typically takes hours for fuel pressure to bleed down.

Item # 2, check valve is different than the one inside the fuel pump. # 2 isn't related to this. I'm surprised to see it's considered normal for fuel pressure to drop to "0" overnight, but as long as it comes up high enough to start the engine right away, that is all that's needed.

I've used the low-cost code readers that supply data, but as you've seen, they respond very slowly. What you might consider is looking on eBay for a Chrysler DRB3. I have one for all of my older vehicles. The first they went obsolete on was the 2004 Dakota / Durango. They were still used up to 2008 on some Jeep models. Depending on the year the scanner was built, they will work back to '98 or '96 models, and with extra plug-in cards, they can all work on all Chrysler products back to '83 models, and they can do emissions-related stuff on all car brands sold in the U.S. Starting with '96 models. For that reason a lot of independent shops bought them, but now that they're obsolete, you may find a local shop with one to sell.

One of the menus with the DRB3 is a "crank / no-start" menu. That would be appropriate for a long crank time too. That screen shows all the data related to fuel, spark, and timing that the Engine Computer sees. The data updates almost instantly, so you can watch to see what's wrong or missing before the engine starts.

For my 2014 Ram truck, I bought a used Snapon Solus Edge from a seller on eBay who always has a few listed as having the latest updates. Snapon charges way too much for their annual updates, so a lot of people, including myself, will never have them updated. Mine is good for up to 2018 models. I'd have to pay $1000.00 for the 2019 update before I could buy the 2020 update for another $1000.00, and so on for every year. It would cost roughly the same to buy a brand new model. They won't let you skip any years. Here again, once it gets too far out-of-date, a lot of shops will just sell theirs cheap and buy a new one. You can look on eBay for one that's really far out-of-date, as long as it covers the 2003 models.

After rereading your first post, please clarify what you mean by, "it takes five or six tries" to start the engine. Do you mean the engine just cranks and cranks but doesn't try to run? Between attempts, do you turn the ignition switch all the way back to "off" before trying again? Do you just get a loud clunk from the starter but it doesn't crank the engine? That is another common symptom that might have an easy solution.

Now you're describing what has happened to my truck when it had a weak battery. I have this gimmick where you turn the key fob, (or press the "Start / Stop" button if you have that style), and the computer runs the starter relay until the engine is running, even though you already released the fob / button. If that is what you have too, check the battery. The cranking system will cut out when system voltage gets too low.

To color this story a little, my truck was a rebuilder with 2,450 miles and two years old when I got it. After my friend rebuilt it, I didn't need it, so it sat unused over winter, and I thought the battery drained as expected, and froze. I buy "reconditioned" batteries for $35.00 from my local battery store. In this case they refused to take the old one for core until I took it home and charged it at a slow rate for three days. After those three days, they rechecked it and it was fine. I'm still using it for other purposes to this day. That is an "absorbed glass mat", (AGM) battery that is treated differently in regard to charge times and rates.

To get the engine started with that weak battery, I needed a jumper pack. With the battery alone, the starter kicked out before the engine started. That reconditioned battery they sold me was a standard lead / acid battery, and it did fail after two years. In this case it would still start the engine but not after running my laptop 'puter for as little as five minutes.

The next $35.00 battery lasted one week less than the 90-day warranty they gave me. They replaced it for free with an AGM battery. With this one, I'm back to running the laptop for over an hour, then it can still start the engine.

If this is offered by one of your local battery stores, you have to know to ask for a reconditioned battery. In some cases they are new batteries that have been sitting on the shelf for too long. Others were sold but didn't solve the problem, so they were returned, typically by business customers, not individuals. They test as good as brand new batteries, but you save a pile.

Just to jump in on this one because I want to clarify what you are seeing with the TPS. I assume you are looking at this with your scan tool and seeing at key on it is 17.9 degrees?

Let's just check the voltage to confirm the sensor is telling us this or it is a scan tool issue.

Unplug the connector and check voltage from pin 1 to 3. You should have 5 volts.

https://www.2carpros.com/articles/how-to-check-wiring

Then plug it back in and back probe the signal in pin 2 and 3.

Let me know what this voltage is and then we can see if we have a throttle issue but if this is hanging open then it can cause a hard starting.

Yeah. The internet is full of confusing stuff. :)

At key on with the engine off, your throttle plate should be 0 degrees or close to it.

I don't remember looking at other 4.7L of this year but I do know that I have looked at enough other Chrysler products and they are all 0 except for Hemi engines.

When the engine is idling it should be slightly open as this is how the throttle controls the idle on Hemi's because they don't have separate IAC valves. So, this is more than likely what people are saying when it is "normal."

However, the 4.7L does have an IAC motor so I would expect the throttle to be 0 as the IAC will allow air the proper amount of air in.

One other way to try and confirm this is add more fuel with starter fluid in the intake and see if it starts quicker. Basically, you have more air coming in if the throttle is hanging open so adding more fuel will even it out.

11% sounds high but the voltage on these sensors is from a half volt to 4.5 volts range. So, of the 5 volts it uses this range so that is normal.

Have you tried using starter fluid to see if the engine will fire faster?

Okay. That will cause a check engine light but there is something to try first.

It is called a clear flood start. If the engine is getting too much fuel, then holding the accelerator to the floor and then starting the engine will cut the fuel injectors and it should start faster.

However, if it is only taking 4-7 cranks then you may not notice a difference in this as well, but it is worth a try.

Lastly, if nothing else is turned up, I would replace spark plugs. I understand they have 50k miles on them but once they are worn it will cause this hard starting issue. So, let's pull them and get a couple pictures and see what they look like.