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Discussion Starter #21
He is right. Missed that with 2lb. That low may be your issue and or the cause of bad VP44's
Curious, was the original lift pump that you replaced on the block? Or did it have the retofit where Dodge put it in the tank?
Good thought, Maxwedge. If the external pump (on the block) is added along with a failed in-tank pump, this is exactly what kind of fuel pressures I would expect. It's very difficult to get much flow through a non-working positive-displacement pump. Some pressure would show at the on-block pump output, but any load on the pump (engine starts) would drop the output way down because of the restriction of the in-tank pump.


SOOOOOO I was trying to diagnose why my genesis trailer brake controller flashes OC every time I turn it in for a few minutes before it quits. And I seen this green wire. I was like huh what’s that for. Come to find out there is a black wire hooked to the drivers side negative terminal. So I decided to follow those wires. They both go to the top of the tank with wire nuts right at the tank. I am going to fix this. But I decided to hook the green wire up to the battery. And boom I heard a humming sound from the tank. So I jumped in the truck and it took it a few seconds to start(head pressure from hard wired pump) took it down the road and she drives like a dream. Seems to be low on power but that cooks just be me used to a trick with 150s and 4.11 and a truck with 6x13 And big turbo. So Iwas trying to suck a softball through a straw. Anyway to hook up this in-tank pump to the factory wiring harness and have both running. Might help fuel pressure? Is the factory fuel pump plug power and ground or power and signal and it grounds to the engine? NO MORE P0216 code
 

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One or the other, IMO. I took out my in-tank pump and used a Vulcan draw straw kit that puts the tube into the factory fuel canister. I've run it down close to E with no problems. Not a big fan of sumps because it's hangs down and thieves can easily get at my fuel.

Great news by the way!
 

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Discussion Starter #23
So I’m probably still better off just eventually buying an Airdog but for now just removing one or the other and going from there. I have a sump on 1 of my trucks and have “great results” besides the lift pump not being big enough to Supply consistent pressure anymore. It’s a 100-4g. So it’s only good for 500 or so
 

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If it is pumping 10-15 lbs steadily all that playing around iwht pumps, sumps lines etc is just you laying, There will be no effect on running. Either it is gettingfuel well or not, be done wiht that until the issue is fixed. If it said 216 internal timing failaure that is a mechanical failure and it takes a lot to set the code, unlike constant electrical issues.
 

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I had a new VP throw a 216. I added some 2-stroke, cleared the code and it never came back. I don't know that the 2-stroke did anything. It may not have come back anyway but I do habitually run 2-stroke. Fix your pressure problem then deal with any running problems and codes that are left.
 

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First off~~you need to find out exactly how each of these lift pumps are wired.

The in-tank pump should have an associated relay which is triggered by the ECM signal that originally powered the on-block lift pump. If the in-tank pump is directly powered by the original ECM signal, that’s too much load on the ECM.

Any aftermarket pump you installed should also be powered through a relay.

Just my opinion, of course, but I see no need to run two pumps in series. In some cases, that puts excessive pressure in the injection pump. In any case, it just adds an extra link in the fuel system. The failure of either pump basically shuts down the system. Have you measured your pressure at the input to the injection pump with both lift pumps running?

If I were in your position, I’d move the on-block pump to the frame near the fuel tank and just use it. This would require installing a draw-straw or a sump to bypass the in-tank pump.

In any case, you need to make sure that you’re not trying to run both pumps directly off the ECM. It’s not designed for that kind of a load.
 

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The two stroke may have freed up a sticking timing piston,
 

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Discussion Starter #28
I believe I am going to eventually go with the fleece In tank pump And from what I can tell right now. Someone retrofitted a pump into the tank and then wired it up their self. It is not factory wiring harness. It has it own green and black wire zip tied together along the frame rail going to the drivers side battery and then used to go to a switch. Whenever I bought it for whatever reason the in tank pump was no longer being power for some reason. So when I give it 12v power direct from the battery it works. But I cannot see where there was ever an I tank pump installed factory. The factory pump was still on the block. And was still plugged in with no jumper wires. It almost looks like previous owner had someone put a pump in the tank and ran it off a switch. So now I have figured out my p0216 code. The original pump doesn’t throw the code now either so both pumps run fine. It was this pump on the tank not working. So like I said I will either get an Airdog and sump or use the fleece I tank unit later down the road. I will get rid of either one in the coming days as I work dark to dark and don’t have a shop to work in. All driveway mechanic for now. No more check engine lights from either pump. And I have no way to check fuel pressure now as it is a 3/[email protected] jic fitting and no longer the schraeder valve like before. I’ll have to run an I line sensor later. I bought the truck cheap and needed it to go down the road without any hiccups before I put any money into it.
 

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You really need to find out what your fuel pressure is. If it's running high (within reason), it's not a problem, but if it's still too low, it's not a matter of if you're gonna be replacing the injection pump again, but how soon. And you can bet that time will come at the least opportune time. And they ain't cheap.

Low feed pressure is probably the number one killer of the VP-44. The Factory Service Manual recommends at least 10 psi at all times. Most folks here like to see 15 psi. I say anything above 10 psi is good. Personally, I like to see it between 15 and 20.

Once again, I say: Just my humble opinion.
 

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Discussion Starter #30
I will check fuel pressure again When I get the chance. The truck sits in the driveway 99% if it’s life. I don’t drive it to work so when I get the chance I will check fuel pressure.
 

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The in tank pump is a "factory" Conversion kit done by a dealer or individual. Not done at the "factory" When it is done properly their is a replacement flow through block of aluminum the goes where old on block pump is. So what yo have is probably somebody installed the in tank pump alone with the rest of the kit. The conversion includes a hot wire relay mounted on the firewall triggered by he lift pump supply wire from the ECM. So to use the in tank pump you should hook it up that way and buy the block replacement or just bypass it by cutting the banjos off and bypassing it with a section of rubber 5/16 or 8mm fuel line and hose clamps. You can not run fuel through 2 or 3 different fuel pumps with some of them not running. That is the reason for you are loosing flow and pressure under load trying to pull o push through a second pump. So get it down to just the in tank pump and run it with a relay and bypass the other(s). Farily simple actually. PS I like my intank pump always 15-17 lb, only 2 lb drop for WOT
 

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Discussion Starter #32
The in tank pump is a "factory" Conversion kit done by a dealer or individual. Not done at the "factory" When it is done properly their is a replacement flow through block of aluminum the goes where old on block pump is. So what yo have is probably somebody installed the in tank pump alone with the rest of the kit. The conversion includes a hot wire relay mounted on the firewall triggered by he lift pump supply wire from the ECM. So to use the in tank pump you should hook it up that way and buy the block replacement or just bypass it by cutting the banjos off and bypassing it with a section of rubber 5/16 or 8mm fuel line and hose clamps. You can not run fuel through 2 or 3 different fuel pumps with some of them not running. That is the reason for you are loosing flow and pressure under load trying to pull o push through a second pump. So get it down to just the in tank pump and run it with a relay and bypass the other(s). Farily simple actually. PS I like my intank pump always 15-17 lb, only 2 lb drop for WOT
This intank pump has no relay. There isn’t a relay on the firewall, and someone has ran wires from the sending unit with wire nuts splicing the tank and frame wires together so I really don’t think it is factory. Seeing as how the factory lift pump would prime and run like normal and the one in the tank had no power going to it until I found the power wire ha going for it. I really think someone bought the in tank pump right before I bought it and never got it working maybe? There isn’t a relay anywhere near the wires.
 

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Yea that is why I said it was a hack job without all the parts, just the pump from a parts store.
 
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