Fuel Pressure Delivery Warning and Check engine light

[Fleetwood_Coupl]

FAULT 1 OF 1
FUEL DLV PRESSR SPN 94 CM 0
DATA VALID BUT BELOW NORMAL RNG
FMI 1 OC 6

got this fault after pulling into campground at idle after several hours at highway speed. Does not store a code and after I clear it, it comes right back. After getting up to about 40 mph it goes away and light goes out, but engine is under-powered until light goes out then it takes off and runs fine at hwy speed. Suspect secondary fuel filter, 6000K miles since it was changed.
I checked to see what Redland truck and RV installed and they put a NAPA 3626 filter on which after researching is only a 6 micron filter and CAT recommends a 2 micron filter 1R-0751 I called them and talked to them, they are trying to tell me thats not it and if it was it would be worse at highway speed and not get better. I have already ordered new filters and will change them but wanted to know if anyone else had this issue or suggestions. Another note, when I arrived here a few weeks ago the light stayed off but I am worried this thing is going to leave me on the side of the road. Fleetwood chassis CAT engine C7 2006

[seeing_the_sigh]

Fleetwood, I sent you a P.M. Thanks, Joe

[Fleetwood_Coupl]

Update, I got my new filters today. One thing I wanted to mention was I filled up again after this started and drove 100 miles to my current location, after arriving here at idle and driving around at less than 10 mph it has not happened again. Could it have been some bad fuel from the prior stop that has worked its way through the system? I guess for piece of mind I will change the secondary and go from there. I did drain the primary for a good few minutes at the first issue and again at fill up and again after arriving here.
Thanks for all the info...

[Fleetwood_Coupl]

ILVMYGT wrote:
Did they change both filters? If not not get the primary filter changed. It if is plugged it will not flow. I would get the CAT 1R-0751 installed ASAP. CATs don't like dirty fuel.

The C7 uses HEUI (Hydraulic/Electronic Unit Injector) system. I would google it and read about it. This is a very complicated system. It used engine oil to inject the fuel. Dirty or old engine oil can cause issues. The HEUI increases the oil pressure in the pump from 500 to 3600 PSI depending load. That oil is use in the injector to push the "intensifier piston" to inject fuel. The intensifier piston is a 7 to 1 ratio. So fuel going into the injector at 1000PSI gets injected in to then cylinder at 7000PSI. There is a lot of wear and tear on the oil.

Clean fuel and oil are you friends.

Yes Sir they changed both filters and the oil at that visit.

[11178adm]

C7 Cat engines have a pressure regulator on the fuel return fitting at the rear of the cylinder head that can fail causing low fuel pressure. depending on the type of failure it can cause low pressure at low or high RPM or both. If my memory is correct fuel pressure should be in the 50 to 60 psi range at idle and 70 to 80 psi at governed speed.
I would also change primary and secondary filters and use genuine Cat on the secondary.

[ILVMYGT]

Did they change both filters? If not not get the primary filter changed. It if is plugged it will not flow. I would get the CAT 1R-0751 installed ASAP. CATs don't like dirty fuel.

The C7 uses HEUI (Hydraulic/Electronic Unit Injector) system. I would google it and read about it. This is a very complicated system. It used engine oil to inject the fuel. Dirty or old engine oil can cause issues. The HEUI increases the oil pressure in the pump from 500 to 3600 PSI depending load. That oil is use in the injector to push the "intensifier piston" to inject fuel. The intensifier piston is a 7 to 1 ratio. So fuel going into the injector at 1000PSI gets injected in to then cylinder at 7000PSI. There is a lot of wear and tear on the oil.

Clean fuel and oil are you friends.

[Fleetwood_Coupl]

Thanks Lawrosa, but my engine is a 2006 C7 so from your quotes (which I cant re-quote)
how much if any of this information would pertain?

[Fleetwood_Coupl]

wa8yxm wrote:
A 2 micron filter would REDUCE system pressure post filter, and I would think the sensor is post filter.. So I'm inclined to agree with Redlands.

On the other hand a 2 Micron Filter will filter out particles that a 6 Micron might let pass.. But I seriously doubt that is the problem.

If you are in range of Redlands. re-visit, they have a good rep for customer service.

Stationary in TX until the end of April, doing the volunteer thing.

[wa8yxm]

A 2 micron filter would REDUCE system pressure post filter, and I would think the sensor is post filter.. So I'm inclined to agree with Redlands.

On the other hand a 2 Micron Filter will filter out particles that a 6 Micron might let pass.. But I seriously doubt that is the problem.

If you are in range of Redlands. re-visit, they have a good rep for customer service.

[lawrosa]

EPA 2010 and later DT, 9 & 10 engines use a fuel module that incorporates many features, including an electric fuel pump, fuel heater and fuel strainer.
-The fuel strainer can be seen when the pump is removed from the filter module. The strainer should be cleaned at the filter replacement interval (30K miles / 43K Km / or 12 months). The strainer P/N is 1899335C91 (see images below)
-Low fuel pressure and Hard Start or No Start conditions can be caused by at least two manufacturers of non OEM fuel filters. See differences in the fuel filter seals here and fuel filter recall G-Letter here.
-Navistar has received complaints that NAPA fuel filter FIL3994 can cause low fuel pressure. CARQUEST and WIX 86994 appear to be made by the same mfg. as the NAPA filter.
-Navistar's OEM fuel filter was developed specifically to work with features that are designed into the fuel filter housing. These features remove air from the fuel system and produce the required fuel pressure, giving the engine optimum performance.
-Calibration updates have been made due to low fuel pressure DTC's 94-1, 94-17 being set erroneously. Do not perform diagnostics for these faults unless there is a starting or performance complaints.
-Update the engine calibration (see calibration scorecard)
-If the vehicle has this code(s) and has a performance complaint then update the engine calibration AND follow step-based diagnostics (at the beginning of this article)
-Some low fuel pressure complaints are caused by a worn fuel pressure regulator valve & spring. Kit 1893801C94 is available to remedy this.
-Low fuel pressure complaints can be caused by the wrong O-ring being installed on the fuel pump

Fuel pressures above 60 psi will not cause low power or performance complaints on this engine

-Fuel inlet restriction should not exceed 8.14" Hg. / -4 psi. High inlet restriction can cause the pump to draw too much current and shut off or behave erratically (this could be caused by an intermittent fuel restriction in the fuel tank or anywhere in the line). Use ZTSE6009 adapter to attach a vacuum gauge to the fuel inlet.

ELECTRIC FUEL PUMP OVERVIEW

At key ON, the ECM closes the fuel pump relay (provides ground via pin C-76) and battery voltage is supplied to the pump. The pump will run for ten seconds (time varies with coolant temperature) and then shuts off. During the run time if the ECM does not detect crankshaft rotation it switches the fuel pump relay off. The key must be OFF for at least 10 seconds and then cycled ON before the ECM will restart the fuel pump.

DIAGNOSTIC TIPS:


The pump has internal overload protection that turns the pump off under overload (high current draw situations). High current draw can be caused by high inlet restriction or restriction in return line to tank. When current limiting protection is triggered, the pump will cycle on and off causing the system pressure to fluctuate until the overload condition is resolved. The pump may eventually turn itself off. This situation can occur without a fault code being set. When the ignition key is cycled OFF for 10+ seconds and ON the pump will restart'''


found that the fdp sensor on the new filter housing was yellow and the original one and new one I replaced old one with is blue, switched the yellow one out with the new blue one and it started reading 75psi. Road tested with the laptop hooked up and it maintained 75psi throughout the trip with no fuel filter dtc.

[Fleetwood_Coupl]

Great just what I need.

[Tom_Barb]

Fleetwood Couple wrote:
FAULT 1 OF 1
FUEL DLV PRESSR SPN 94 CM 0
DATA VALID BUT BELOW NORMAL RNG
FMI 1 OC 6

got this fault after pulling into campground at idle after several hours at highway speed. Does not store a code and after I clear it, it comes right back. After getting up to about 40 mph it goes away and light goes out, but engine is under-powered until light goes out then it takes off and runs fine at hwy speed. Suspect secondary fuel filter, 6000K miles since it was changed.
I checked to see what Redland truck and RV installed and they put a NAPA 3626 filter on which after researching is only a 6 micron filter and CAT recommends a 2 micron filter 1R-0751 I called them and talked to them, they are trying to tell me thats not it and if it was it would be worse at highway speed and not get better. I have already ordered new filters and will change them but wanted to know if anyone else had this issue or suggestions. Another note, when I arrived here a few weeks ago the light stayed off but I am worried this thing is going to leave me on the side of the road. Fleetwood chassis CAT engine C7 2006

Filtration rate should not cause this fault. fuel actually flows thru a 6 micron filter easier than a 2 micron.
but Cat is known for not liking air in the system. because it causes pressure problems.
This actually sounds like a pump problem.