P1556 After Delete

[petem]

Hello everyone,

I just purchased FORScan to help diagnose an issue I have after deleting and tuning my 2014 F-250 Power Stroke. I did a complete EGR/DPF delete, crankcase bypass, and DPK for my 6.7 diesel. After I did that, I keep getting a code P1556 which is a cylinder 6 injector circuit range/performance code. I've unplugged and plugged the electrical connection of the injector back in and cleared the code but it will pop back up. I've taken it to a mechanic who said he does not see an issue with the injector and the power balance shows that all injectors and cylinders are good. I bought FORScan today to help me diagnose this. I did see that there's an option to "reset the high pressure fuel system learned values". Is this something I can try to help with this code? Will it have any undesired effects on my tuned truck? BTW, the truck has an EZ LYNK tune on it.

Thanks in advance.

[boosted_diesel]

Hi there, welcome along.

The fault code you mention is specifically for the electrical circuit's performance. So the parts in question are the pcm, the wiring to the injectors and the injectors solenoid itself. These are all the parts of the circuit.

If the cylinder balance seems fine then it's likely a wiring or connection issue rather than an injector, even more so if unplugging then re plugging it allows the code to go away for a while.

If it was me I would start with all the basic tests first as they are free and easy. Equip yourself with what's needed and do a pin drag test on the wiring plug for that injector to make sure the pins are making good contact.
You could also do the standard tests on the wires from the pcm to the injector, test continuity, check resistance then load test them.
If they pass all the tests then your likely looking at an injector that's intermittently bad as it's less likely to be the pcm, unless they are a known issue. To be sure if it was an injector you would need an oscilloscope and you would need to connect it while the problem was happening, what you would find is the waveform would be different between a good and the bad injector, that would confirm that.

If it did come down to a bad pcm, then it would likely be a failing driver within the pcm for the injector circuit. This can usually be repaired by specialists who do that work.

Hope this sets you on the road to fixing it

[boosted_diesel]

Forgot to mention swapping diesel injectors would tell you if it was the pcm or an injector.

[Don Ridley]

You should check out the FTE forum. It is the resource for F250 Forscan issues.

https://www.ford-trucks.com/forums/1768 ... guide.html

But your problem makes be mechanical and the FTE forum is also the place to find help.

[petem]

Thank you both for the replies. I'll try to check the continuity of the wiring. I was told that there's a way to check it using the center harness plug from the ECM and the bottom row of the of that harness. I'll try to find out exactly how to do that.

For what it's worth, I did do a live oscilloscope scan on the truck using FORScan and that injector seems to be operating like the others. I put all 8 injectors on the dashboard along with the "injector fault". All 8 injectors appear to be functioning the same and the injector fault is not showing a fault.

I am wondering if it is something in the tune, but I've reached out to them and they don't think that it is. The engine has power, doesn't miss, and doesn't blow smoke so I'm kinda at a loss. I brought it to a diesel mechanic who has a high end Snap-On scanner and he couldn't find any issues with it either. He was able to check the power balance and the power balance is a smooth, straight line. He was able to cut off injectors on the fly and each time he did that, including injector 6, you could feel the difference in the truck.

I'll keep digging. Again, I appreciate your replies.

[boosted_diesel]

It's defo a circuit issue matey.
How expensive a scantool is doesn't really make a difference.

I meant to connect a proper oscilloscope (even a handheld) to the injector on the ground side (be sure to use an attenuator to stop the scope board getting spiked) and view the waveform in detail, spotting the waveform difference takes knowledge which I'm not sure if you have done before?
You also have to be sure the problem is occurring when testing or it will appear that they are all fine.

It may simply be that the one injector has a higher resistance in its circuit than the others if it always runs fine. It doesn't take much to log a code and bring a light on, 0.4 ohms too much on an airbag circuit will bring the light on.

[petem]

It's defo a circuit issue matey.
How expensive a scantool is doesn't really make a difference.

I meant to connect a proper oscilloscope (even a handheld) to the injector on the ground side (be sure to use an attenuator to stop the scope board getting spiked) and view the waveform in detail, spotting the waveform difference takes knowledge which I'm not sure if you have done before?
You also have to be sure the problem is occurring when testing or it will appear that they are all fine.

It may simply be that the one injector has a higher resistance in its circuit than the others if it always runs fine. It doesn't take much to log a code and bring a light on, 0.4 ohms too much on an airbag circuit will bring the light on.

Yeah, I don't have a proper oscilloscope, nor do I effectively know how to use/read one. I guess it's just odd to me that the code didn't show up until after the delete and tune.

[boosted_diesel]

It's defo a circuit issue matey.
How expensive a scantool is doesn't really make a difference.

I meant to connect a proper oscilloscope (even a handheld) to the injector on the ground side (be sure to use an attenuator to stop the scope board getting spiked) and view the waveform in detail, spotting the waveform difference takes knowledge which I'm not sure if you have done before?
You also have to be sure the problem is occurring when testing or it will appear that they are all fine.

It may simply be that the one injector has a higher resistance in its circuit than the others if it always runs fine. It doesn't take much to log a code and bring a light on, 0.4 ohms too much on an airbag circuit will bring the light on.

Yeah, I don't have a proper oscilloscope, nor do I effectively know how to use/read one. I guess it's just odd to me that the code didn't show up until after the delete and tune.

If the code wasn't there before the egr delete and remap then there is probably an issue with their work.

Can I ask did they dyno tune it or just flash it with a computer?
As just flashing it is so unprofessional words can't describe it.

[petem]

It's defo a circuit issue matey.
How expensive a scantool is doesn't really make a difference.

I meant to connect a proper oscilloscope (even a handheld) to the injector on the ground side (be sure to use an attenuator to stop the scope board getting spiked) and view the waveform in detail, spotting the waveform difference takes knowledge which I'm not sure if you have done before?
You also have to be sure the problem is occurring when testing or it will appear that they are all fine.

It may simply be that the one injector has a higher resistance in its circuit than the others if it always runs fine. It doesn't take much to log a code and bring a light on, 0.4 ohms too much on an airbag circuit will bring the light on.

Yeah, I don't have a proper oscilloscope, nor do I effectively know how to use/read one. I guess it's just odd to me that the code didn't show up until after the delete and tune.

If the code wasn't there before the egr delete and remap then there is probably an issue with their work.

Can I ask did they dyno tune it or just flash it with a computer?
As just flashing it is so unprofessional words can't describe it.

It wasn't dyno tuned by them - EZ LYNK just offers the delete kit with the ODBII connector to flash one of their "canned" tunes on it. I have 4 tunes to choose from since I have the on-the-fly 5 position switch. I've tried 3 of the 4 tunes available to me with the same result.

[boosted_diesel]

Have you considered just reflashing the pcm with the standard software again to see if the problem goes away?
You could always reflash the tune again after.