Dreaded P0216 code, help/advice

[Doubletrouble]

 This conversation has really turned out to be informative and interesting. I have already ordered my Raptor lift pump and will install it but as this discussion progresses I will be watching. I'd like to see more testing done on this and possibly a special write up showing all results mainly because this goes against everything I've ever read on the lift pump pressure requirements and so on. I'm am in no way saying it's wrong on either side. This is all new information and I appreciate @Tractormanfor bringing it to light. This could change alot of things in the cummins dodge realm. 

[wil440]

One thing  @Tractorman mentions is that the VP was used a lot certainly over here/ Europe and while they did fail it was nowhere near like you guys and I doubt there are that many Gen2 Cummins in Rams over here to make a comparison.

The one thing you can say is that all are used in much smaller engines yes the VP is different slightly but it's still a VP

Also here vehicles tend to be bean tins after 100k as in squashed, yes some do high mileage most don't, smaller country smaller mileage

I am a firm believer in over capacity of anything mechanical as in "if it needs to do so much design it to do twice what is needed" a bit like older V8's never stressed at all, I wonder if 24v 5.9 is a step too far for the VP certainly when first used not so bad now maybe due to people fixing the poor materials of the various parts used and other various tricks like 2 stroke oil for you guys

[Doubletrouble]

 I don't think it's a bad injection pump. It does seem a little over complicated to me but I'm no expert. From what I've read I think it could be a better pump if better materials were used in preparation for the ultra low sulfer diesel fuels of today. They were put into service when diesel had more lubrication. That's why we use the 2 cycle oil is to add that factor back into the fuel to compensate.

[Mopar1973Man]

With larger injectors your fuel duration is much much less over stock which has much longer duration to pump the same amount of fuel. Hence that why when you look at the stock trip computer if you injector sizes the MPG goes up. Like Thor is only +50HP injector be the MPG display on the trip is 2 MPG higher than actual. This shows the shorter duration that the ECM is seeing. Just with my injector set up increasing to 320 bar well now my injectors are closer to 310 bar and still going being I've got an idle around 7% compared to 13% when they were new.

 

As for the common P0216 code. Well after seeing it with my own eyes and taking a VP44 apart. The piston is a very hard steel that is black anodized. Now the sleeve in the pump was originally brass sleeved back in the day and now its also harden steel sleeve now. So when the lubricity is low (US ~520 HFRR) the galling will start. Once the piston is sticking enough that when the ECM calls for timing changes and it doesn't move in a about 300mS then the VP44 tells the ECM set the code P0216. Now the pump I've got here to get the piston out of it you MUST heat the entire body around the piston with a propane torch to expand the body enough to get the piston out. That's how wedged up it is with galling. Now I though for a parts show piece I would clean that up a bit with a file and make it fit better. Nope not happening, that steel is very hard. P0216 code is fully a lubricity failure now being fuel pressure problems have been fixed with better pumps. 

 

As for whats inside the PSG. Don't let it fool you too much. There is only 2 devices it controls. Throttle and timing. That's it two leads to the hydraulic control valve for timing and electromagnetic solenoid for the fuel pin. There is a bit of diagnostic software and software limitations that the PSG will accept like throttle value in decimal is from ZERO to 4,095 which when converted to hex is 000 to FFF. This why any CANBus only tune can get +60 to +65 HP. There is only so much you can squeeze out of the limitations on the communication. This why wiretapping allows more because now a tuner will hold the fuel pin open longer of the piston stroke in the VP44.

Edited January 31, 2022 by Mopar1973Man

[Max Tune]

What tractorman says makes complete sense. It will relieve a bit of worry if I see pressure below 14. As long as the VP has positive pressure delivered to it, it is producing it's own higher pressure to keep fuel flowing through the return line, if I'm reading that right. Personally, I'll keep my pressure between 14-20 just because, but it's reassuring to know if it drops a bit lower my VP isn't in self destruct mode....

 

Thank you.👍👍👍

[Mopar1973Man]

One small problem. That higher internal pressure is used to fill the pistons in the pump. There is no springs on the pistons to return them to outward but fuel pressure. The return flow is the un-used fuel that is returned to the tank. So that higher internal pressure is not seen at the return port. Being the return is routed directly to the distributor head on the other port. One in to the pistons and the other out leaving what is bypassed. 

 

The port towards the delivery valves is the return port and the port towards the shaft is the supply from the vane pump internally. Then the input fuel is also got little screens in the ports to protect the pump from debris.

 

 

Pistons are laid out on the distributor head as you can see the fuel pressure is needed to push the pistons out to reload for full volume. The cam ring and shoes/rollers will push the fuel up to pressure all 3 pistons at once.

 

As for the return routing... You can see the raised hump in the body routing to the return port from the distributor head to the forward port being the supply port is a open hole to the void below the PSG which is remove. This chamber is used for cooling the PSG since the PSG is heat sinked to the fuel.

 

[Tractorman]

I posted this information on another thread a while back.  The credit goes to Mopar-muscle and his helpers in performing a VP44 return flow test using a flowmeter back in April of 2001.   I am not familiar with the tuners used back then, but that really doesn't matter.  The documented results clearly show that lift pump pressure has no bearing on fuel volume that passes over the 14 psi overflow valve and returns to the fuel tank from the VP44.  

 

I am amazed that this kind of testing was done back in 2001, but here we are today with lots of folks still convinced that if lift pump pressure is below 14 psi, there is no fuel returning to the tank from the VP44.

 

I think it is interesting that when I performed a return flow test using a measured container on my truck last summer, both of my test results at engine idle with lift pump operating and at engine idle with lift pump bypassed and not operating were both 19 gph.  This compares closely to Mopar-muscle's 18 gph using a flowmeter.  His flowmeter is probably a bit more accurate.

 

I appreciate the comments of those who are participating in this topic.

 

- John

 

What Mopar-muscle has to say,

 

Test # 1

well some of you guys ain't gonna like this , especially those led to believe (and those that believe it) ... the bigger is a MUST theory .

spent a couple minutes running some tests with a DIGITAL/mechnical flow meter and a MECHNICAL fuel pressure gauge , items under test ... 2000 RAM , DD2's , DD TTPM on level 2 (??) and a HOT PE , ( all levels tested the same at WOT)factory pickup , factory lift pump , factory fuel filter housing unmodified , all banjo bolts intact and unmodified except the banjo to the input of the lift pump is replaced with a 90* swept areoquip type -6AN hose end , the bolt at the lift pump had the schrader cut off and drilled and tapped to a 1/8 npt ( for the gauge) and the banjo fittings between the lift pump and the fitler housing have been drilled to 9/32nd . again all banjo bolts are not drilled out as i have on my ram ( test conducted on the DTT RAM ) .

we installed ( LaserBob is helping me and getting #2 fuel poured on his head ) a Sonnex digital flow meter ( inside ID is 5/16") in the return line back to the tank , cut in right at the trans crossmember . gph numbers are fuel returned to the tank .

DD2 , DD TTPM (True Torque Power Module)
FP volume
idle 11 psi 18gph
cruise 8 psi 24gph
WOT 2 psi 30gph


DD2 , TTPM , HOT PE ANY LEVEL
FP volume
idle 11 psi 18gph
cruise 8psi 24gph
WOT 0 psi 30gph


yes you read that correctly , fuel pressure went to 0 and the fuel volume back to the tank did not change from WOT with 2 psi . the truck did NOT stumble , buck , spit , fart , fall on it's face , nothing , ran like all heck at 0 psi , i will note , my truck ran the same at 0 psi with the DD3's , EZ and a HOT PE .

tomorrow we will install -8 lines and an HP carter pump , take flow readings in exact same spot and see what the results are .

 

Mopar-muscle, Apr 24, 2001 Report

 

Test # 2

 

well , here we go again , todays test was interesting to say the least , and we believe we have it figured out .

added the carter HP 15psi 110gph pump on the frame rail next to the tank , -8 bulkhead in the bottom center of the tank , -8 line to the pump , -6 line from this pump to the inlet of an unmodified factory 2000 fuel filter housing , the rest of the system is as delievered from the factory except for a banjo bolt that had the schrader cut off and tapped to 1/8 npt for the gauge , the digital flow meter in the exact same location reading flow back to tank after the tee on the engine .
 

with DD2 , DDTM (True Torque Power Module)
psi volume
idle 11. 5psi 18gph
cruise 9psi 24gph
WOT 6 psi 30gph


with the HOT PE on any level
idle 11. 5psi 18gph
cruise 9psi 24gph
WOT 4psi 30gph

with the addition of the new pump and larger gravity fed pickup point the flow to the tank did not change , though pressure was up , the carter having an internal bypass is living with the backpressure on its output .

the concenus is the VP44 is the restriction . the return line from the pump is only returning the excess fuel from the VP44's own internal pump , the more you feed it the higher the backpressure on the line to the pump .

the guys with the large pumps , bigger lines and regulator mounted as close to the VP44 as possible have a large amount of the excess flow returned directly to the tank , this is not a bad thing ,( except that at a low fuel level it is possible to foam the fuel in the tank with the large amount of fuel dumping back into it from 2 sources ) but is really overkill as the vp44 uses a set amount of fuel and this is proved by the higher pressure seen with no increase in flow back to the tank .


[This message has been edited by Mopar-muscle (edited 04-26-2001). ]

 

Mopar-muscle, Apr 25, 2001 Report

 

 

[Max Tune]

Very interesting and well done testing.

 

I have a question. Back when our trucks were new, Dodge had enough warranty claims on failed VPs to move the lift pump from the engine (I think) to in the tank. There were still enough failures that airdog, FASS and other high gph pumps were brought to market. Granted, if the lift pump dies, it's not good for the VP, but my question is, we're the VPs failing back in the day from lift pump failure or did the VPs get updated with better materials to increase longevity about the same time the aftermarket pumps were coming to market, making for a coincidental belief that more pressure was the answer?

If the VP was updated with better materials, could they last with the cheaper lift pumps that Dodge put in the tank for their "fix" of the problem?

 

Woulda, Shoulda, Coulda......

 

Very interesting discussion.......

[Great work!]

I still have my stock lift pump torn apart in a box. It looks like a well built OEM style pump but nothing fancy. The pump, motor and brushes look pretty  beefy. I think the mounting location was a big mistake. The heat and vibration from the engine plus drawing fuel up hill from the tank was what killed them. The ECM powering them directly was another mistake. Not having a fuel pressure warning system was the biggest blunder I bet all the warranty claims wiped out any savings from skipping a $5 pressure switch and snubber.

[Silverwolf2691]

Bit of all of the above..

 

The factory lift pumps as far as i know, do not have a check valve to bypass a failed pump. So the internal vane pump of the vp44 would have to try to pull through another pump.. not good. Bosch started to beef up the vp44 for the galling and what not. Think it was brass that Mopar1973Man said earlier.. then got sleeved with hardened steel. From what he also described, the timing piston is a hardened tool steel, probably around Rc 60-65. Think as hard as a file.. 

 

@Great work! has good points as well in regards to the fuel pump as well.

 

@Great work! is the factory pump a vane pump? I heard that it was a diaphragm pump a long time ago but then heard that that was false..

[Great work!]

Mine was a gearotor style looks like an old Carter type. The motor runs dry and only has bronze bushings on the shaft instead or bearings.

[Doubletrouble]

 I recently placed my order for my lift pump. After all this conversation I'm kind of second guessing what pump I should have purchased. 

[Tractorman]

3 hours ago, Max Tune said:

Granted, if the lift pump dies, it's not good for the VP, but my question is, we're the VPs failing back in the day from lift pump failure or did the VPs get updated with better materials to increase longevity about the same time the aftermarket pumps were coming to market, making for a coincidental belief that more pressure was the answer?

 

You pose a good question here.  I strongly believe the reason is as you suggest, "or did the VPs get updated with better materials to increase longevity about the same time the aftermarket pumps were coming to market, making for a coincidental belief that more pressure was the answer?  When my VP44 pump was replaced under warranty in 2005, it was suggested that a lift pump failure was the cause.  I didn't buy that at the time.   Before I took the truck into the dealer, I strapped a fuel pressure gauge to my driver's side wiper arm and drove the truck for five days back and forth to work - a total of 250 miles.  The lift pump never missed a beat and stayed well within its specs

 

3 hours ago, Max Tune said:

If the VP was updated with better materials, could they last with the cheaper lift pumps that Dodge put in the tank for their "fix" of the problem?

 

Absolutely.  Part of the warranty along with replacing my VP44 was installing a relayed in-tank lift pump.  Ironically, that lift pump put out 6 psi at idle and 3 psi at wide open throttle, far less pressure than the previous block mounted lift pump.  I presented that information to the service manager and the diesel mechanic.  The response was, "yes, they knew that, but that is what Dodge wanted them to do."  At the time I was not concerned because my background experience in hydraulics basically says that if there is still a positive pressure at the inlet of the VP44 injection pump under high load demands, then the VP44 is getting plenty of fuel for operation and cooling.

 

I drove the truck with that in-tank lift pump for over 160,000 miles with zero performance problems.  I replaced the in-tank lift pump with a used DDRP-02 FASS frame mounted lift pump, not because the in-tank lift pump failed, but because if I did have a lift pump failure on a road trip, I did not want to have to be towed.  The used FASS pump has performed fine for over 110,000 miles.

 

1 hour ago, Great work! said:

I think the mounting location was a big mistake. The heat and vibration from the engine plus drawing fuel up hill from the tank was what killed them. The ECM powering them directly was another mistake. Not having a fuel pressure warning system was the biggest blunder I bet all the warranty claims wiped out any savings from skipping a $5 pressure switch and snubber.

 

I agree.  With these lift pump problems, it was easy to blame the VP44 failures on the lift pump. 

 

When my VP44 pump was replaced under warranty, I was disappointed that I received a remanufactured VP44 pump - not a new one.  Later, after learning that Bosch had addressed several problems inside the VP44 and the PSG as well, I was very glad to have received a remanufactured VP44 pump.  It was good that Bosch made these changes, but the general public never really knew this process was going on because Bosch never said anything about it.

 

11 minutes ago, Doubletrouble said:

 I recently placed my order for my lift pump. After all this conversation I'm kind of second guessing what pump I should have purchased. 

 

@Doubletrouble, glad to be of help - making things more confusing for you, that is!

 

Again, I appreciate all of the comments and feedback from all of you!

 

- John

Edited February 1, 2022 by Tractorman

[Doubletrouble]

29 minutes ago, Tractorman said:

@Doubletrouble, glad to be of help - making things more confusing for you, that is!

 It's OK. I'm still going to move forward with my plan for now. Next time around I may go a different route? Time will tell but for now I just want my truck back on the road. Lol

[IBMobile]

1 hour ago, Great work! said:

Mine was a gearotor style looks like an old Carter type. The motor runs dry and only has bronze bushings on the shaft instead or bearings.

When the factory lift pump died, I took it apart to see what was in it.

 

Pump head with filter screen

 

[Max Tune]

Imagine how long things would last if it wasn't for the bean counters trying to save a penny here or a penny there....or even less.....

 

 

 

 

Wait, I think it was called the 30s-50s......

[Mopar1973Man]

6 minutes ago, Max Tune said:

Wait, I think it was called the 30s-50s......

[Tractorman]

I would like to know two very important things that would help resolve some of the mystery surrounding the VP44 fuel system operation.

 

     * Thing One:  How about manufacturers of lift pumps providing fuel flow performance charts for lift pumps they sell?  These flow charts would provide valuable information. 

 

           Example   LIft Pump A fLows:

           

                            100 gph @ 0 psi

                              90 gph @ 5 psi,

                              80 gph @ 10 psi.

                              70 gph @ 15 psi, and so on

 

     * Thing Two:  How about Bosch providing the pump displacement information for the VP44's internal vane pump in terms of cubic inches per revolution?  This would allow for easy calculation of fuel flowing from the internal vane pump at any given engine rpm.  I have never seen this information posted anywhere and it would be very valuable.  This one piece of information alone would give a much better understanding of fuel flow inside the VP44.

 

@dieselautopower, I see that you post every now and then to help resolve engine performance problems for people posting, so I am reaching out to you for help in finding answers for the two questions I have posed above.  I am asking you because you may have resources that are unavailable to customers who use these products.  

 

Thank you in advance for any information you may be able to provide.

 

- John

[Doubletrouble]

 I think that would be a great idea to calculate those numbers if you could obtain them. I'd love to see the results.

 For now still patiently waiting for my Raptor to arrive.

 If we do get the above mentioned info it would be very interesting to see what the outcome is. 

 Still second guessing my purchase at this point. 

 Maybe should have just replaced the fass ddrp with another? I don't know.......ugh

[Mopar1973Man]

Buy a Flow meter then you cantest it yourself.

 

CGOLDENWALL 1 inch Turbine Flow Meter Digital Fuel flowmeter for Water, Diesel, Kerosene, 2.65-23GPM/10-90LPM, 1" NPT Thread (1" Flow Meter) https://www.amazon.com/dp/B09G9878DK/ref=cm_sw_r_apan_glt_i_Q0K3BDH1R5NRM5WY5SC6?_encoding=UTF8&psc=1