2015 6.2 No Start/Runs On One Bank

YukonTyler · July 22, 2016

Have an interesting one - belongs to the guy the next bay over, but a couple of our brightest minds have got sucked in.

Story goes 2015 6.2 Super Duty was at another dealer up the highway for ~5 weeks with this issue which they could not resolve. Warranty history shows the truck got a new PCM and 8 injectors. Towed to us. Also noted fire damage (dry chem all around the intake, charred loom) to the engine harness atop bank 2 valve cover.

Crank no start, runs on brake cleaner through the intake. No codes due to the recent PCM. Found long and short trims along with flexfuel way out to lunch on bank 2. Unplugged bank 2 upstream UEGO and she fired up but with random consistent dead misfires on 3, 5 and 8. After idling for a while the misfires cleared themselves. ~50 km was put on the truck (along with a bunch of idle time) before it was released the customer. In the end it got a new UEGO, and after that was installed the trims came back to normal.

Towed back in today for another crank no start. Hmmmm. Same thing - runs on brake cleaner. Wiggle the harness near the PCM and it fires, but runs only on bank 2. Bank 1 trims super lean (+29), suspect injectors not firing on bank 1. Bank 2 trims normal.

Test injectors with a noid light - during the no start find almost no triggering, and during runs rough find proper appearing triggering on the affected bank - but still unconvinced of their mechanical function. Remove rail and confirm no fuel being injected on bank 1 during runs rough. Swap injectors side to side (while still out in mid air) suddenly all eight fire. Reassemble and find proper function - for now the truck runs very well.

We check injector 12v supply, load test wires, check injector driver circuit continuity between the injectors and the PCM. All good. Have cam/crank sync. Unplug injectors while running and it throws immediate circuit codes. Verified coils are firing.

We want to throw an engine harness at it due to the erratic nature of the fault combined with the fire damage, but we're yet to do a test which condemns the wiring in any way. Intermittently seeing the injectors fail to fire while at the same time triggering a noid light would usually be a slam dunk for plugged injectors, but immediately swapping the injector to the good bank and seeing it fire puts that idea to bed.

Running out of ideas in a hurry. Does the PCM have an independent ground for each bank of injector drivers? Our wiring diagrams do not go that deep. If so, I'm wondering if resistance on the ground side for one bank of injectors is playing with their ability to carry load while at the same time being too minimal to code.

Any other ideas?

Between the three of us we are pretty darn smart, but there's something that we're missing. We don't want to fire the parts cannon at it (harness) but it's getting near that point ...

8WA Sman · July 22, 2016

I would load test or voltage drop all PCM + and - while wiggling the harness. I would also do this to the injector control and power circuits. So no codes in any modules, they didn't mess up the calibration/flash files by any chance. If you unhook the injectors when it is not triggering does it set fault codes.

YukonTyler · July 22, 2016

Ran great again this morning. Got thinking more about this last night and electrically it is working properly. Disconnect an injector and immediately it immediately codes the circuit.

I'm leaning toward a mechanical fault in the fuel rail. I think that there may have been debris that lodged itself at one point in the main fuel line where it enters the rail, and later migrated to the inlet side of the fuel crossover line. This hypothesis is definitely one constructed to fit the symptoms, but when I start overlaying all of the passing electrical tests then I'm left with little else.

I suspect that when we moved the rail around yesterday and debris may have been dislodged and removed. Going to run this one for a week or so and see what happens.

Matt Saunoras · October 12, 2016

What ever happened with this one?

I have one here now, it's a high mileage 6.2 that runs on bank 2 until the bank 1 short fuel trims go way positive (38%) and those cylinders come back. Flex fuel pid is 85% also. First thing I found was the gas cap was off.

When I hooked up the PVT/VMM and took a fuel sample something that I assume is water is also present in the fuel. My relative fuel injector test will not complete with multiple random injectors experiencing low flow. Fuel pressure and leak down were okay.

For some reason whenever I was performing the relative flow test the engine ignited a small amount of spilled gas around #7. When I pulled #7 coil out the boot and coil well are filled with white corrosion. The boot is ripped also so I have no idea what else is going on .

8WA Sman · October 12, 2016

What ever happened with this one?

I have one here now, it's a high mileage 6.2 that runs on bank 2 until the bank 1 short fuel trims go way positive (38%) and those cylinders come back. Flex fuel pid is 85% also.

I had a '14 5.4L that had a complaint of hard start/runs rough, the FF pid was way off. I cleared the KAM and relearned the FF, vehicle has been fine since. Not sure if that's what going on with yours but I thought I would throw it out there. :shrug:

I also had one that had bad fuel, I burned a sample of fuel on a clean piece of steel & inspected what was left. If I remember what ever was in there didn't burn very well.

Matt, since it looks like you are going to be doing gas drivability, GSB G0000017 & G0000079 might be helpful if you don't already know.

YukonTyler · October 12, 2016

In the end we suspected bad fuel which caused misfires and set the FF_INF out of sorts. I think that the erroneous UEGO readings lead down the garden path. Final fix wound up being fresh fuel, dump the fuel in the rail, KAM reset and new plugs. That got it running in closed loop which then let the FF learn. All was well at that point.

Matt Saunoras · October 12, 2016

I did sell 8 injectors, a rail and a tune-up. I am going to replace whatever coils look bad also and remove the tank and clean. There is definitely water in this fuel, it clearly seperated as it sat longer.

Keith Browning · October 20, 2016

Ethanol

YukonTyler · November 2, 2016

I got another one like this today (and potentially another one right behind it waiting outside).

- Towed in cranks no start. No codes CMDTC or KOEO.

- Verified fuel to the rail. Fuel quality looks okay, not full of water and it burns on the floor. FF_INF 9.8%. Long and short trims near 0.

- Noted a very dirty engine air filter and a dirty MAF. Went down the MAF path. Installed a known good sensor and a new engine air filter. Disconnected battery terminals and shorted them together over the lunch hour. Come back to a reset FF_INF at zero. Crank no start remains

- Pulled a plug - dry as a bone (had suspected possibly flooded).

- 1/2 can of brake cleaner down the intake and it fires up, runs rough for 10 minutes and gradually clears. Drive it for 70 uneventful kilometers at highway speed. FF relearns at 11% and my trims settle back in toward zero. Fuel system monitor passes. Shut the truck off and immediately start it again with no issue.

At this point I put it on the rack to diag some aux lamps inop and to do an oil change. It is in the air for 45 minutes and when put back down it is again a crank no start.

- Starts with brake cleaner again. Runs very rough and does not want to clear. At idle misses on cyl 1, 4 and sometimes 7. At half throttle to full throttle it levels out and runs reasonably well.

- Backprobe injector 1, install a noid light and verify it is firing electrically. Pull a plug on cyl 1 and see it is dry.

This truck is a Shell unit and is very dirty, just like the last one which belonged to Nalco Champion. Our working theory: Sand/sediment in the tank (small amounts seen in fuel sample) migrates up the lines (no longer filtered) and into the rail. In the returnless system it cannot return back to the tank and instead gets stuck in the rail. The sand settles atop the injectors in the rail once the truck is off for more than a half hour. At idle fuel pressure in the rail is low and the fuel cannot find its way through the debris and out the injectors. At throttle fuel pressure ramps up and is able to punch some fuel through the blockages.

Tomorrow morning I am going to do my best to pull the rail in a clean fashion and without spilling too much fuel. I want to flush the rail and injectors over some coffee filters and see what comes out of this thing. I suspect that 8 injectors and a rail will take care of the issue. Pretty interesting stuff!

YukonTyler · November 3, 2016

Looks like I'm on the right track. Tons of debris suspended in the fuel came out of the rail, and that's without trying to flush anything out.

I also have another one with an identical concern. It, too, has dirt/debris in the fuel sample I pumped from the tank.

I have a rail and eight injectors on order for the first unit. I anticipate that will take care of things.

tonybullitt · November 4, 2016

Sounds like you got it. Wonder if there is a reasonable way to add a fuel filter?

Matt Saunoras · November 4, 2016

I checked in the book and it says the pump contains a non-serviceable "lifetime" filter. I had one here I was going to take apart but ultimately I said fuck it and threw it out.

Also the one I did was fixed by a rail, 8 injectors and a tuneup. There wasnt much water in the tank

YukonTyler · November 4, 2016

I dropped the tank on one truck - spotless. However, there is a ton of debris in the 'reservoir' of the pump module.

The pump module has a check valve as the inlet to its reservoir. Once debris gets in it cannot get out. In essence the fuel pump module becomes one big vacuum cleaner for the tank. Moreover, the sock/inlet for the fuel pump is oriented right to the bottom so it sucks directly from the debris.The sock was full in this specific location. I then took apart/destroyed the pump module in order to get to the lifetime filter. It was in poor condition.

12 000 km on the truck I pulled the tank on with 250 hrs. 30 000 on the other one with 1300 hrs.

That is out of the rail on the Shell unit.

Filter internal to the fuel pump module on Nalco Champion.

Sock on Nalco Champion.

FP module reservoir on Nalco Champion.

A new pump, rail and eight injectors has each truck repaired and working properly. This one was fun. When a guy thinks fuel debris plugging eight injectors he usually has a diesel on his mind and not a gas job.

YukonTyler · November 4, 2016

Sounds like you got it. Wonder if there is a reasonable way to add a fuel filter?

We have one of those napa kits for repairing the plastic lines. I wonder if a guy was to cut out an ~8 inch section and use the gun in the kit to put Ford-style quick connect fittings on the cut ends. Then you could quickly snap in a Motorcraft filter from right off the shelf.

tonybullitt · November 5, 2016

Sounds like you got it. Wonder if there is a reasonable way to add a fuel filter?

We have one of those napa kits for repairing the plastic lines. I wonder if a guy was to cut out an ~8 inch section and use the gun in the kit to put Ford-style quick connect fittings on the cut ends. Then you could quickly snap in a Motorcraft filter from right off the shelf.

I would offer the customer the option. If it's feasible to install. Would be way cheaper to replace filters then fuel rails and injectors.

jimmy57 · November 5, 2016

This is puzzling. In the early 2000's the move to no serviceable filter was due to the pump pickup strainer getting finer. The strainer became the primary filter and the upstream filter got to a much smaller particle size capture to catch pump wear particles to save injectors as a secondary filter. Something is wrong that these trucks are letting that stuff get by. If it lets the sediment in tank pass then it would let brush and commutator pieces pass.

The other observation: do these guys store their fuel in a pond next to a busy dirt road? Where is all the dirt coming from?

DieselD · January 25, 2022

I would like to bring this one back from the dead which helped a stubborn crank no start 2013 F250 6.2 we had in the shop recently.

Ironically this one was a mine truck as well and almost always covered from top to bottom in a nice layer of mud with the consistency of concrete. Pulled the tank down to check for contamination and debris and found a similar amount like the above pictures in the bottom of the pump but not enough to cause an issue(so I thought) replacement of the pump got pressure to the rail but still a no start. After checking and double checking the injectors and coils are receiving their respective commands and knowing the engine tries to run on starting fluid the injectors are the only thing left. While some debris was present in the rail and top of the injectors it certainly was not enough to think it would cause a no start but ended up changing all 8 injectors and and fuel rail and she fired right up after.

Thanks to this thread it helped confirm my theory of an injector problem. Its not often we run into needing to change practically the whole fuel system to fix a crank no start!