cylinder balance Fault

[bshull]

While driving around this afternoon it was warm 95 deg I noticed my idle was higher than usual. I have had this problem before and thought nothing of it. Today I decided to look further.

Reading the active codes I have a 98 Cylinder balance Fault #8 and 94 Cylinder balance fault #5. In history codes I have in addition to the two above I have 91, and 95 cylinder balance faults #7 and #4.

The cylinder balance fault tells me that the cylinder is not firing as it should. From research this can be due to a valve train failure not allowing enough oxygen into the cylinder or a fuel delivery issue.

The times I notice this issue is when it is warmer out. When the outside temp is cooler I do not notice this problem. Could this be PMD related? I do have a spare and I can change it out if anyone thinks this could be a possibility.

The injector pump has about 30 thousand miles on it, and the injectors have about 20 thousand miles on them. I do not think this is a valve train issue since it can clear up. The PMD is remote mounted in the bumper.

Any thoughts?

Thanks

Brian

 

[NVW]

While driving around this afternoon it was warm 95 deg I noticed my idle was higher than usual. I have had this problem before and thought nothing of it. Today I decided to look further.

Reading the active codes I have a 98 Cylinder balance Fault #8 and 94 Cylinder balance fault #5.should be #4 In history codes I have in addition to the two above I have 91, and 95 cylinder balance faults #7 and #4. should be #1 and #5

The cylinder balance fault tells me that the cylinder is not firing as it should. From research this can be due to a valve train failure not allowing enough oxygen into the cylinder or a fuel delivery issue.

The times I notice this issue is when it is warmer out. When the outside temp is cooler I do not notice this problem. Could this be PMD related? I do have a spare and I can change it out if anyone thinks this could be a possibility.

The injector pump has about 30 thousand miles on it, and the injectors have about 20 thousand miles on them. I do not think this is a valve train issue since it can clear up. The PMD is remote mounted in the bumper.

Any thoughts?

Thanks

Brian

Just some corrections in red.

I'm not sure on any causes though.

 

[ak diesel driver]

lift pump?

 

[bshull]

I am running a Walbro FRB-5. I have a pressure gauge after the lift pump, before the factory fuel filter and the lowest pressure I have witnessed is 5 psi. It normally runs 7 - 8 psi cruising down the road. Is this pressure OK?

Thanks

Brian

 

[ak diesel driver]

good pressure maybe check for air to eliminate the fuel side of things. clear hose on ip return

 

[ak diesel driver]

also on reread your pressure guage is before the filter possible filter restriction

 

[NVW]

Those pressures are good, the only thing is a clogged FFM would prevent the IP from seeing that pressure.

I don't know myself if low fuel pressure would set a cyl. imbalance, air could.

 

[bshull]

I will check for air tomorrow, the fuel system is fully modified. The FFM filter was changed 2000 miles ago but I will look into it. After the FFM I have the feed the beast mod. I also have a Racor filter pre-lift pump and it's filter was changed 2000 miles ago. I guess if a fuel connector somewhere in the pre-lift pump chain could be letting in air.

Tonight for an experiment I did change out the PMD, I will see if there is a change tomorrow and report back about air in the return line.

Thanks

Brian

 

[NVW]

Those pressures are good, the only thing is a clogged FFM would prevent the IP from seeing that pressure.

I don't know myself if low fuel pressure would set a cyl. imbalance, air could.

I hadn't seen that Les already answered those questions.

 

[Chief915]

I will check for air tomorrow, the fuel system is fully modified. The FFM filter was changed 2000 miles ago but I will look into it. After the FFM I have the feed the beast mod. I also have a Racor filter pre-lift pump and it's filter was changed 2000 miles ago. I guess if a fuel connector somewhere in the pre-lift pump chain could be letting in air.

Tonight for an experiment I did change out the PMD, I will see if there is a change tomorrow and report back about air in the return line.

Thanks

Brian

Since you've documented the fault numbers that were stored already....

I would clear all codes, and see what comes back. If it's the same exact codes (cylinders) again that points to something specific to those cylinders (like an injector). If balance codes come back, but for different cylinders than before, it points toward something that could effect any cylinder (like air in the fuel, pmd, etc).

Doing this won't tell you exactly what part is causing the problem, but it will help narrow it down.

 

[WarWagon]

X2 on air.
Also I have had a bad time with anything but a course screen before a lift pump. My experiments with a CAT water filter before a Walbro and then a Mallory Gerorator pump have had the engine stalling. Extreme suction is required. This extreme suction is pulling air at over 2500 sustained RPM. But I have not so clean tanks. Thus a need for a large filter.

I have to weigh extreme suction vs. an air leak and decide how much suction it should normally handle. So far when I pull the hose off the fuel filter air valve from the booster pump I am using to prime the system there is a pretty good hiss. So too much suction may be finding air.

Myself I will push through the large cat filter and use one of the inline glass screen filters pre lift pump. That setup worked although the dirt loading was quick for me. I should have less if it now with 'better' non biodiesel fuel.

 

[buddy]

I have a 12 micron pre-filter water separator for years with the Walbro FRB5 and FRC10, and havent ever changed it, but I do recommend 30-micron.

The fuel pressure post FFM is much lower, about 30% so with clean filter, or worse.

Air in the fuel is likely, or check with a scanner what your warm idle fuel rate is, and injection pulse width, could be an IP issue. Are you sure its timed right with a TDCO learn?

 

[Brooklyn Tow]

Add a qt. of ND SAE30 to the fuel......

JMO

 

[bshull]

So here is what I know from tonight's journey of understanding of the 6.5 turbo diesel.

I installed the clear hose on the fuel return and surprise surprise, bubbles of air. Not a few but a bunch. So I started under the burb where I installed a Racor fuel filter/heater. All hose connections looked to be ok, all hose connections at the fuel pump looked to be ok. So I opened up the fuel lines at the Racor filter, grabbed the trusty air compressor and dialed the pressure down to 30 psi. Back blowing the tank with the fuel cap on did not show any leaks that I could detect. Pressuring the fuel filter to the pump did find a problem.

As soon as I pressured the filter it started to leak at the bottom inspection/heater bowl. It was at this point the whole bottom of the filter cut loose and removed itself from the vehicle. Lesson learned, no more pressure testing fuel lines!

After reassuring the neighbor I was ok and that it was supposed to happen :rof: I looked at the parts. The bottom attachment that holds the water separator/heater bowl on was not glued/sealed too well to the filter.



So here is the unassembled filter:



This is what it should look like:



Put it all together, re-primed the system, washed the diesel off the motor from bleeding the filters, now my OPS that controls the Kennedy OPS relay mod seems to not work. I can start the engine and keep fuel pressure until the 30 second timer quits then the pressure drops. So no test drive to see if I am still getting air in the system.

We will see tomorrow,

Brian

 

[Brooklyn Tow]

Nice find....Speed Diagnosis

 

[bshull]

Ok to try to finish this up, after changing the first fuel filter I still had air in the system. I rechecked the fuel system pre lift pump with no luck, still air bubbles. I attached another clear line from the IP to the fuel return system. No bubbles coming from the IP so my problem had to be at the injectors.

I ordered an injector return line kit from Kennedy Diesel and put them on, bled the system, no air bubbles! So far I do not have an active cylinder Balance fault. I still show cylinder 5 & 8 in history but it is not active.

For the next step I will try some two stroke oil in the fuel but I think my problems are over, for now.

Thanks for all the help

Brian

 

[ak diesel driver]

good to hear