Good morning,

So a couple days a go my 04 Ram 1500 4.7 crew cab short bed just shut off at a stop light. Fuel pump was priming at the time but it was a crank no start situation. After having it towed home we did some further troubleshooting including going over the fuses, relays, TIPM to no avail. The following day the fuel pump was not priming anymore, so I began to troubleshoot the ASD relay. Checked resistance when it clicked over. Everything was fine with the relay. I checked the schrader valve on the fuel rail. No pressure. I then went to the connector on the fuel pump. All reading on the voltmeter were where they should be. I then determined (with a second opinion from my father) that it was the fuel pump. He agreed.

After replacing the pump, I primed it a few times to get fuel back into the system and build pressure in the rails. Low and behold, it fired right up like it didn’t miss a beat. It drove perfectly fine to the gas station where I filled up, it drove perfectly fine about 15miles back home. (Now remember that last part)

This morning it fired up fine, warmed up fine. However, the moment I got on the freeway and gave it some throttle just as I had the day before, it seems that it has gone into limp mode and thrown the p0463 code for the level sensor.

My truck has almost 200,000mi on it. I’m guessing the swapped the tank to a 34 or 35 gal one with one of the previous owners and I was not aware they made multiple different pumps. I know I’ve had to put 30gal in one time when my fuel level was at 1/8th of a tank.

Would I be right to assume that I purchased and installed the wrong pump? It is the Delphi brand from autozone.

***UPDATE***
1/27/20
1700

I checked the grounding straps, all is well there so I picked up a 34gal fuel pump as I was able to confirm that I indeed have the larger tank.
R&R’d the other pump with this pump.
Seemed to work just fine until, again, I hopped onto the freeway. Gave it some throttle until it downshifted. Bucked and went back into limp mode.

I still have the p0463 code (I assume it’s due to not finishing its cycles). But I now have a p0339 code and a p0300. Crankshaft and multiple misfire respectively.

From what little knowledge I have, I’ve seen p0300 show up due to limp mode but I’m slightly confused on the crankshaft position sensor (p0339) as I just replaced it yesterday as well as the camshaft position sensor.
Im back to square one.

***UPDATE 2***
1/28/20
1700

Today I went through the steps described by Hey You in another thread to make the PCM forget everything it’s learned. As expected, all codes were cleared and the truck is now NOT in limp mode. I decided that I will drive it around very easily to see if it will throw a code that’s unrelated to the fuel pump situation as that may be the underlying cause. Outside of that, the truck is running just as it used to.

Just to reiterate here, here are the steps to make the PCM forget everything.
-Disconnect negative at the battery
-Turn headlights on for 3-5min (what worked for me)
-Turn headlights off
-Reconnect negative battery cable
-Verify codes were cleared

I did this to clear any pending codes as well. So far so good but I would not consider this problem solved. I’ll update if anything arises.

***UPDATE 3***
2/20/20

After driving for some time since the last update I had received codes for the cam and crank position sensors. I was unaware that autozone sold second hand parts. Never again will I purchase sensors from them. I ordered myself both of the sensors mopar brand. Replaced them yesterday and it’s like driving an entirely new truck. At this time I can say with certainty that the problem has been resolved.

I lay it all out like this for anyone that may come after me with these issues.

Thank you for your help in solving this matter.
&
Thank you for taking the time to read this essay. 😀

 

One of the possible causes I found was this:

The ground circuit is open, or ground path may have high resistance due to rust or missing ground strap on fuel tank.

Check connections, and make sure everything is where it should be. Delphi makes some good stuff, it's *possible* you got a bad one, but, not the most likely scenario.

 

Thanks for the reply.
I’ll give it a look and see about the grounding straps. We replaced it without dropping the tank, instead we removed the bed. Found quite a gravel pit of rocks built up on top of the tank. Maybe something was jostled loose when we cleaned those rocks out.

Im just baffled that it ran just fine right after it was replaced but the next morning (today) it decided to go into limp mode.

Would you happen to know if accidentally using a 26gal pump in a 34gal tank could cause this issue? I couldn’t find anything on it.

Thanks again.

 

On that, I don't have any idea. On the 2nd gens, the tank was just longer, not deeper...... I don't know about the third gens.

 

Updated my post to reflect today’s troubleshooting.

 

What brand crank sensor?

 

Im sorry, I could’ve sworn I responded to you.
Its a dorman.

UPDATE. I saw what you said on another thread about how to make the ecu forget everything it’s learned. I did just that and I’ve been driving it easy to see if it will throw a code unrelated to the fuel pump. Drove it all day yesterday, 1/28/20, haven’t had a single issue.

My thought is that the residual code from the 26gal fuel pump was still causing it to go into limp mode.

I’ll update again if anything changes.

 

Still and all, I would be looking for a Mopar crank sensor.......

 

I will look into it. So far i haven’t thrown any codes.

 

So you were undoubtedly right there, I purchase mopar brand cam and crank sensors. We’re back in business. I updated the OP to reflect that for anyone that may have the same issues.

Thanks so much for your help and suggestions.
👍🏻