Air in fuel system.

[mpreiss321]

2011 Int’L prostar cm871 engine getting code spn 94 fmi 18 air in the Fuel system. Not the first time for this code. Have changed the fuel filters recently. Fuel mileage avg is 5.9 mpg with avg load of 25k. Installed 6 rebuilt injectors 50k miles ago. When I turn the key on to hear the fuel pump running, I can hear it bubbling. Engine has 832k miles. Fuel pump and all 4 actuators appear to be originals since they’re all still painted red.

Where do I start?

I did nothing about the code the last time it popped up since it appears to be an intermittent problem.

I have recently changed the turbo with actuator ( work done by international) because the old actuator was frozen and the old turbo spewed oil. Since then it’s lagged in power.

[Waterloo]

(08-24-2018 )mpreiss321 Wrote:  2011 Int’L prostar cm871 engine getting code spn 94 fmi 18 air in the Fuel system. Not the first time for this code. Have changed the fuel filters recently. Fuel mileage avg is 5.9 mpg with avg load of 25k. Installed 6 rebuilt injectors 50k miles ago. When I turn the key on to hear the fuel pump running, I can hear it bubbling. Engine has 832k miles. Fuel pump and all 4 actuators appear to be originals since they’re all still painted red.

Where do I start?

I did nothing about the code the last time it popped up since it appears to be an intermittent problem.

I have recently changed the turbo with actuator ( work done by international) because the old actuator was frozen and the old turbo spewed oil. Since then it’s lagged in power.

SPN 94 shows this on Quickserve...

The gear pump draws fuel from the fuel tank through a suction fuel filter and an anti-drainback valve. The gear pump develops between 1724 and 2620 kPa [250 and 380 psi] of fuel pressure. The fuel flows through a pressure fuel filter and fuel shutoff valve to the fueling and timing actuators and rail fuel pressure sensor.

Component Location
Use the following procedure for a detailed component location view. Refer to Procedure 100-002 in Section E.

Shoptalk
The fuel pressure is monitored by the ECM. If the rail fuel pressure is lower than an acceptable level for a given set of engine operating conditions, the fault code is logged.

NOTE: One possible cause of this fault code is a damaged or sticking drain-back valve located in the fuel supply circuit in the integrated fuel system module (IFSM). The IFSM is located directly above the fuel lift pump.

https://quickserve.cummins.com/qs3/pubsy...fc482.html

Here is the FMI 18

Component Description
The fuel delivery pressure sensor responds to pressure changes in the fuel manifold of the integrated fuel system module (IFSM). The fuel delivery pressure sensor has a 5 volt supply circuit, a sensor signal voltage, and a return circuit.

The electronic control module (ECM) provides a 5 volt supply to the fuel delivery pressure sensor using a common sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The fuel delivery pressure sensor provides a signal to the ECM on the fuel delivery pressure sensor signal circuit. This sensor signal voltage changes, based on the pressure in the fuel manifold. The ECM will detect a low signal voltage at operating conditions, such as during an idle or a deceleration. The ECM will detect a high signal voltage during high engine load operating conditions.

The gear pump draws fuel from the fuel tank through a suction fuel filter and an anti-drainback valve. The gear pump develops between 1724 and 2620 kPa [250 and 380 psi] of fuel pressure. The fuel flows through a pressure fuel filter and fuel shutoff valve to the fueling and timing actuators and rail fuel pressure sensor.

Component Location
The rail fuel pressure sensor is located on the bottom front corner of the IFSM. Use the following procedure for a detailed component location view. Refer to Procedure 100-002 in Section E.

Conditions For Running The Diagnostics
This diagnostic runs continuously when the engine is operating.

Conditions For Setting The Fault Codes
The ECM detects that the fuel delivery pressure is lower than the minimum pressure level.

Action Taken When The Fault Code Is Active
The ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.
The engine may not start, or the performance output of the engine could be limited, due to the low fuel pressure condition.
Conditions For Clearing The Fault Code
The ECM will turn off the amber CHECK ENGINE light immediately after the diagnostic runs and passes.

Shoptalk
Verify the ECM calibration is correct. Check the calibration revision history found on QuickServe™ Online for applicable fixes to the calibration stored in the ECM. If necessary, calibrate the ECM. Use the following procedure in the appropriate Troubleshooting and Repair Manual for the engine being serviced. Refer to Procedure 019-032 in Section 19.

It is possible to swap the connections between the aftertreatment fuel pressure sensor and the fuel delivery pressure sensor. If this occurs, Fault Code 2215 will intermittently go active and the engine will run rough and will surge at low idle. If these symptoms are present, make sure the fuel pressure connections are connected properly.

The fuel pressure is monitored by the ECM. If the rail fuel pressure is lower than an acceptable level for given engine operating conditions, the fault code is logged.

NOTE: One possible cause for this fault code is a damaged or sticking anti-drainback valve, located in the fuel supply circuit, in the integrated fuel system module (IFSM) which is located directly above the fuel lift pump.

NOTE: Another possible cause for this fault code is a loose or missing hot start & stall orifice, located inside the bore above the rail fuel pressure Compuchek™ fitting, in the integrated fuel system module (IFSM) which is located directly above the fuel lift pump.


Refer to Troubleshooting Fault Code t05-2215.

https://quickserve.cummins.com/qs3/pubsy...fc482.html

No clue if the links will work, I used my EIN to pull these up on Quickserve...

Looks like a possible fuel pump or possibly the fuel actuators? The actuators, if that is your issue, tend to start failing around the 800,000 mile mark.

[Chamberpains]

Is this code coming on when your driving or running the truck and the check engine light came on? Or did you just find it on the dash display as logged code?
You can often get this code logged from changing the fuel filters. It's just the nature of the beast when you change the filters and air gets in the lines.
But if your getting this going down the road or other times then you have a problem else where. Do you have a Davco filter on the truck? If so, run the truck and watch it to see if air is in the see thru bowel. Where do you hear the bubbles at?

Yes, your actuators could be shot. Rawze has posted on here, how to check them out. It's worth doing. Checking them will only cost you a gasket if the gaskets are not reusable. Replacing a bad fueling/metering actuator will be costly but worth it.

The lagging in power after the turbo replacement can be a couple things. The big one I can think of is air leaks on the CAC and piping. Loose clamp, cracked CAC, bad intake gasket, leaking sensor. Pressure test your entire engine and check for leaks. There are a couple posts on here about how to do that.