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Replaced lift pump and injection pump, still losing all fuel pressure


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Posted (edited)

hey guys! Im new here, and new to the cummins world,  so please bare with me!

 

I recently picked up a 2002 ram 3500 dually, 6 speed. 

There are absolutely no modifications the the truck except a brand new raptor frrp 100 gph lift pump,  and a brand new thoroughbred diesel injection pump.

 

My problem before was, i started up, warmed up, and left the house,  made it about 10 minutes down the road before i started bucking and misfiring,  come to find out i had lost all fuel pressure and got the amazing code of p0216.

 

I went ahead and replaced both the lift pump and injection pump, checked voltages on the plugs, checked the numbers on the iat, checked the numbers on the map sensor,  and everything  checked out, i checked grounds, batterys, everythings fine.

 

After i replaced the lift pump and injection pump, i drove around for about 3 hours with idle pressure at 20( set from factory) and driving/ wot around 13-15. After driving for 3ish hours, it started bucking and skipping on me again like a misfire, and my fuel pressure was perfect at idle, but completely zero in any type of driving .

In neutral,  if i rev for about 5 seconds, it as well drops completely to zero.

 

I checked the pump by removing the line and running it to a 5 gallon bucket, it moved quite a bit of fuel just bumping the starter. The pump itself has no inline screens , so i know its not clogged.

The fuel filter was changed a few days prior to the new pumps with the Baldwin pf7977. It starts up on a dime everytime,  and currently has no codes on the key trick, or a scanner.

 

Any ideas on where to go next?? Im stumpped and just lost.

 

A recap- when i drive, my fuel pressure goes from ( i adjusted the regulator a few days ago per thoroughbred diesel tech instructions) 17psi straight down to zero as i slightly increase rpm.

 

Im sorry for such a long post and thank you in advance for reading my Short novel! Thanks guys!

Edited by Jacob_harley
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It might be the screen in your fuel pickup module, they can plug up over time. I helped a TDR member with the same issue as you, this is what we found:

 

There are two screens in the module. One on the bottom of the sump and one in the little plastic canister with the suction hose attached. It was plugged solid.

Strainer 1.JPG

Module.JPG

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Posted (edited)

On both my trucks I completed my fuel system modifications by removing those screens using a straight piped draw straw. Then adding a pre lift pump large canister type filter. You either have clogged screens, or an old in tank lift pump you are drawing thru, or a clogged tank vent.

 

The clogged tank vent is very rare and can test to see if she runs better by removing the fuel cap and go for a run, but most likely you have clogged screens in the tank. So dumb for Dodge to put those screens in the tank when it needs an accessible pre lift pump filter, esp. on a diesel fuel system.

Edited by JAG1
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Posted (edited)

Replaced my in tank pump when I did the mod to it. Top had a crack and screen was very dirty. I had the same issue as you. Only after I installed my airdog. It was pulling fuel out of the in-tank pump faster then it filled. 

Edited by ColoradoColt
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Thanks for the quick replies gentlemen! As far as I know,  there is not an in tank pump,  just the one on then side of the block. But, with the other info given, im going to drop the tank to be sure, as well as check the screens. Ill do that tonight and post an update and pictures as i make progress! 

 

Side question,  how do i post images? Haha

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The two 01s I've been involved with had the pumps on the engine block and still had a screen "sock" as shown above. Mine had over half a beer can full of trash coating it. Removed that, added draw straw and inline screen (think old truck fuel filter), moved lift pump to frame and gained back 7 PSI.

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Posted (edited)

1.  get rid of the soda can lift pump, they dont provide enough fuel to cool the VP44 nor pressure (eventually will kill a VP). go mechanical or electric.

 

2. did you replace the check valve on the VP44? if not, it could be worn and not holding pressure to the VP thus your possible cause of loss of fuel psi.

 

3. when was the fuel filter inspected/replaced?

Edited by CUMMINSDIESELPWR
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1 hour ago, CUMMINSDIESELPWR said:

1.  get rid of the soda can lift pump, 

 

3. when was the fuel filter inspected/replaced?

 

He said he just changed the filter. He also installed a Raptor pump....soda can??

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Yup I typically suggest the AirDog out here. I won't suggest the FASS because of the filter being in the impact path.  If anything hangs below the frame rail it can be hit while offload. The last FASS I installed had more problems with gelling and freeze ups. Rear tires kept throwing snow on the filters and pump motor till it just quits. AirDog can be hind much easier like mine is hidden behind the transfer case and skid plate protects the filters. 

 

 How To Install an AirDog 150 Fuel System - Fuel - Mopar1973Man's ...

 

Even with temps as low as -40*F and now over 350k miles on this system I've NEVER gelled once. I've lost the first pump after 250k miles. Now this pump is still going and I'm at 415 k miles now. Fuel temps are nice and low too below 120*F normally.

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Ok guys, i just finished up for the night. 

Fyi, i live in west texas, so gelling isnt necessarily a concern i dont think. The 5500s ive driven over the last 8 years here didnt ever have an issue, unless these older trucks have a reason they do?

 

So i dropped the tank , and i do not have an in tank pump. I was Slightly upset about that because i was hoping that was it haha.

 

The screen on the bottom of the housing was completely torn to shreds,  and the screen inside the housing was somewhat dirty,  not enough to kill fuel pressure in my honest opinion.  

 

The tank itself wasnt very dirty,  but it did have a small green ball, and two small black blocks inside of it floating around.

 

I pulled the inlet fuel line and blew air through it to make sure it wasnt clogged. (It wasn't)

 

When i bought a new injection pump, it came with a new check valve, ill take it off tomorrow and check if it releases with 14psi.

 

The filter was changed recently (when this all started) and yes, i did change over to the raptor frrp 100. 

 

This is killing me because ive put over 1k miles on this truck since i bought it. 

 

If pulling the tank didnt fix it, only other things i can think of is

a). Clogged return line

B). Faulty check valve

C). Faulty new injection pump 

D). (This is where you experts give me your ideas ?)

 

Could a bad/ multiple bad injectors cause this?? It dosent smoke, nor does it skip while idling,  it could idle all day long without an issue id say.

 

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Check your lift pump by connecting directly to battery, by passing the ecm, If problem goes away it probably an ecm or wiring  issue, if it’s still their I would say defective lift pump or VP. In your first post I think you stated you had this issue before you replaced both lift pump and VP?

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Posted (edited)
15 hours ago, NIsaacs said:

 

He said he just changed the filter. He also installed a Raptor pump....soda can??

i guess i cant read...   i read it twice and didnt catch this lol  must have been tired.   soda can lift pump (oem small lift pump on side of block)

 

 

 

ive never heard of a VP causing loss of fuel pressure, my money is on faulty lift pump valving

Edited by CUMMINSDIESELPWR
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Ill call thoroughbred diesel here in a bit to.see what they say! 

I've got the pump rigged up to the battery with alligator clips already(thats how i drained 30 gallons of fuel)! And it didnt skip a beat, so once its all back together, ill try to run it from the battery.

 

Yes i had this same issue before the new lift pump and new injection pump, it went away for about 2 hours while i drove around town, had great fuel pressure,  then all of a sudden, nada!

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Try driving it with the pump hot wired and see if it holds pressure. It is possible the 12v circuit from the ECM is failing. Is your lift pump normally connected to the ECM pigtail for power?

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It may be a long shot l dont know. Back when l first joined we saw this issue of the ECM circuit failing a good bit. That's why the after market electric pumps came with a new wiring harness and relay. These took the load off the ECM and used the oe pig tail for the trigger for the relay and power came from off the ECM,

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Dripley, thank you for the info! 

 

I got everything hooked back up tonight,  luckily my fuel guage works, and i used an old yukon fuel pump, to pump about 10 gallons back into the truck. 

 

Ive been driving it and idling on and off here for about 45 minutes,  fuel pressure stays at 17 idle, and about 12 at driving/wot.

 

That being said, i also took the map sensor, and iat sensor and cleaned the heck out of them. 

 

As of right now, its driving perfectly fine. Ill keep driving tonight and Tomorrow and see what happens.

 

If it fails again,  im almost wiling to bet the ecm is having hiccups, or the injection pump hates this truck. 

 

Ill keep you guys posted! And again, thank you to everyones whos chimed in, im so appreciative and humbled that theres still people out who will dedicate their time to help others. Especially over the internet!

 

Side note... how the heck do i post pictures lol

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Hope your on the right track, not an uncommon thing for the lift pump circuit to fail through the ecm, but if it proves so, their are ways to wire it up with relays and such to make it safe, 
Maybe some one could chime in with IBmobiles lift pump relay diagram, I’m working a lot in a no cell service area so posting is limited ,

 

Or you could go the mechanical fuel pump route like I did and not have to deal with it  lol!  

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Posted (edited)

When at idle have someone watch the gauge and turn up the regulator for fuel pressure to 22 psi and then back down to around 7. Do this a few times as it eliminated problems on both my rigs when both got new Raptor 150's that were not behaving correctly. Mike the MoparMan gets the credit for this and solving my F/P issues.

Edited by JAG1
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3 hours ago, 01cummins4ever said:

Maybe some one could chime in with IBmobiles lift pump relay diagram

If the ECM lift pump circuit is ok wire in an electric lift pump this way. 

 

This is what I came up with if the ECM lift pump circuit failed and the the other ECM functions are OK.

 

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Evenin fellers! 

 

Just got back from a 70 mile drive,  and whadya know, it drove perfectly.  Cruising and wot around 10-12psi, idle right now is set at 17

Im going to constantly keep an eye on it though just incase the ecm is acting funny making it cut in and out.

 

Thank you for the diagram ibmobile!! 

 

You guys are an awesome bunch! 

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On 7/9/2020 at 7:24 AM, Jacob_harley said:

Evenin fellers! 

 

Just got back from a 70 mile drive,  and whadya know, it drove perfectly.  Cruising and wot around 10-12psi, idle right now is set at 17

Im going to constantly keep an eye on it though just incase the ecm is acting funny making it cut in and out.

 

Thank you for the diagram ibmobile!! 

 

You guys are an awesome bunch! 

I'd be concerned at 10 to 12 psi cruising and wot. I'm around 20 at 1800rpm ish on mechanical Assassin and thats through 2 micron filters

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