Rail Pressure Troubleshooting

[Mopar1973Man]

2 hours ago, 2500ctd said:

Reminds me of emulsified water in the fuel. 

That was my thought too.

 

2 hours ago, 2500ctd said:

how can you tell there is 2 stroke in there?

Color. 2 Cycle Oil tints the fuel that strange blue-green color.

[AH64ID]

On 1/31/2016 at 7:41 PM, 2500ctd said:

Well the problem did evolve into an fca. Except now I would be putting in my third fca. Gotta be something else.

Problem started as a hiccup during shifting. Got worse to where it is undrivable. Swapped in a new ca. Truck ran till I switched fuel filters. Won't maintain fuel rail pressure. Sometimes after startup rail pressure hangs around 21k. When it hits idle, trying to take off pressure drops to around 1500. It will normally catch and not stall.   Swapped in another fca. Ran fine then later after the testdrive, went to go back out. Truck doing the same thing. I really doubt I got 2 bad fca in a row. Only running a smarty touch with egt.

 

If the rail pressure is that high at idle you don't have a HPRV issue, which you have tested, and I am going to guess you have a bad FCA or Rail Pressure sensor. Really those are the only two things that will cause high rail pressure at idle.

Program the truck stock and see if any codes pop up. The Smarty tuning may disable a code or two that could help with troubleshoot... but then again maybe now.

How long does the truck sit between running? I have found that the Touch will drain the batteries in 2-3 weeks and have to unplug mine when it sits more than a few days.

 

On 1/31/2016 at 5:22 AM, angus said:

15volts sounds a little high. Most alternators regulate around 14.5 maximum output.

Depending on ambient/battery temperature the 3rd gens will call for 15V+.

[2500ctd]

just over the weekend. During the winter cold starts, when it isn't plugged in almost doesn't crank fast enough. Plugged in for about 3 hrs before I leave and starts easier. Batteries are old. I don't think they'll last another winter.

I will keep that in mind about the smarty. Ill return it to stock and then keep it unplugged till I needed.

 

That would be the 3rd FCA. Not saying it cant be, just I don't buy it. Also with the cloudy fuel I could have other issues.  The pressure appears to be working. Truck sounds/behavior mimic the RP on the smarty. I will see if I can test the sensor. should be a 5V sensor. Nothing to difficult......famous last words.

Edited February 15, 2016 by 2500ctd

[AH64ID]

There are other things that the RP effects, so you could have a bad sender and have it mimic... that being said it still sounds like a FCA even if it is your 3rd.

Know anyone you can swap one with locally for troubleshooting?

How old is your fuel filter?

Cloudy fuel won't make it run max rail pressure, but bad fuel can damage things but it has to be bad for a while.

[2500ctd]

I have around 15 miles on the fuel filter.

When the issues started I swapped the FCA which was within a year of my last one. Under warranty. When I picked that one up I got a new fuel filter. Swapped FCA's. Ran fine. Swapped the filter and then it ran like crap. Got another FCA ran fine till the next morning. I have no codes, Havent checked recently just after the new FCA went out. No codes. Ill program the truck back to stock and scan for codes.

 

Smarty is showing rail pressure desired at 6000 at idle, and the actual is 26112. Good thing I guess is during  the HPRV test there was no leakage. Bone dry. At least that isn't leaking.

No one to swap FCAs with. After swapping out the 2nd one, I drove the truck down to return it. Next morning,  max rail pressure.

It is slow to build rail pressure cranking but after it starts it maxes.

Edited February 15, 2016 by 2500ctd

[AH64ID]

I am pretty sure the OEM PRV will leak at 26K psi, so that makes me lean back towards rail pressure sensor.

It's a relief valve that should allow excess pressure by and since the highest OEM pressure is 23,206 it would be okay to dump at 26K.

 

26,112 is as high as the OEM sender goes.

 

[angus]

Personally I would get rid of that fuel before proceeding any further. You see the evidence in the banjo bolt of what is going on in your fuel system. Which could also affect the Rail pressure sensor, the FCA, or even the COV, and God knows what it may be doing to your injectors. Rail sensors are pricey. So I would check the voltage before running out and buying one.

[AH64ID]

That corrosion on the banjo bolt appears to have been there a while. How long have you owned the truck?

[2500ctd]

Started dropping the tank yesterday. 

Only owned the truck since February '14

 

[2500ctd]

Pulled tank. Nothing obvious, minus Cloudy fuel. Is there a way to raise the tank vents? I'm almost thinking water might have gotten in that way.  I thought dodge had a fuel tank vent tsb or severe duty vent kit?  

Also trying to use the lift pump to drain the tank. It'll run about 5 seconds and then quit pumping like its sucking air. Worked fine in the truck. Wonder if the free flow of the pump is faster then fuel can flow into the module. During pumping it has a solid stream until it sucks air. Top of tank is dirty. Wow. 

[angus]

Are you referring to the vent hose that connects to the filler neck? Why do you suspect the vent being a point of moisture entering the fuel tank?

The actual vent in the rear of the tank should be at least as high as the frame rail.

Edited February 18, 2016 by angus

[2500ctd]

the two little barbs on each end of the tank maybe a 1/4 hose would fit on.

I have a flat bed and had to redo the filler neck. refilling kept tripping the nozzle. I don't think the filler tube vent is a source for contaminates but can be cleaned up a bit. 

[angus]

The barb in the front should be your fuel return, and the one in the rear should have a hose connected with a check valve in the end of it. unless you drive through extremely deep water? I don`t see how that could be an issue. The one on the filler neck is there to vent pressure while fueling

Gudge posted a thread in this sub forum titled "truck died on the highway and will not start". He had experienced two rail pressure sensor failures. One which failed low, and the later failed high. He provided an in depth analysis of diagnosing his problem. If you skip to his closing comments you can find the voltage values he found for the two bad sensors, and the correct value for the new sensor. When you get your fuel issue resolved, I would check that first.

Edited February 18, 2016 by angus

[AH64ID]

The return goes to the fuel pump module, which is not pictured since it is removed. 

 

There is a severe duty vent kit offered. I believe you want 68061341AA with a long bed. 

[angus]

14 minutes ago, AH64ID said:

The return goes to the fuel pump module, which is not pictured since it is removed. 

 

There is a severe duty vent kit offered. I believe you want 68061341AA with a long bed. 

 Ok.. vent 101 revisited !  What is the benefit of a severe duty vent kit?

[AH64ID]

It moves and improves the vent filter for heavy dust environments. 

[angus]

So the front and rear vent are connected by a Y  with a filter at the end.. I always thought the filter was also a check valve as well. Is that incorrect?

[Wild and Free]

On ‎2‎/‎7‎/‎2016 at 10:45 AM, JAG1 said:

Bob, just some suggestions for reliability which may not solve your problem.

Get rid of the inside the tank lift pump and go with a Fass with the filters. Cut out the screens inside the tank and get the 1/2'' drawstraw so your not picking up fuel thru the factory drawstraw which has a very small screened cartridge on it..

Get rid of all banjo bolts by going with 1/2'' fuel lines.

Get rid of the factory APPS and get the Timbo Apps.

Sometimes I think the guys around here miss these thinks just to make have to post.

This is on an 05 CR, there is no Apps, last that used them was early 03 cr's yet., also the in tank pumps are super reliable now and the CR cp3 doesn't require the fuel that the VP44 needs. A 2 micron filter added between the OEM filter and the CP3 is adequate on these.

Edited February 18, 2016 by Wild and Free

[2500ctd]

Next thing after the fuel is the pressure sensor testing. I will check that thread.  

I saw water pooled around the tank vents. Hence the vent relocation. 

When I pulled the filler tube hose off I saw a little dirt that got between the hose and tube.  Also looks like a little dirt on the bottom of the fuel module screen.  I have a plan to fix that.  

I have a flatbed so I have around 7-8 inches of clearance above the tank. Enough for water and dirt to splash up there. I do play in the woods as well. 

[2500ctd]

Riddle me this: when I did the test the fuel looked like emulsified water. Now, that same sample is clear. It's 56° now. I wonder if this diesel is a winter blend? 

tends to make me think it was not a fuel issue.   

 

Edited February 26, 2016 by 2500ctd