Misfires on all cylinders in bank 1 - Even after all new coils & plugs

[BlackBear]

I have misfires on all cylinders in bank 1. Replaced all coils, plugs, and one injector in the cylinder that always throws the first misfire code (coded it with ISTA) and still have misfires even after swapping MAF, TMAP, and all oxygen sensors side to side. Misfires stay on bank 1.

Someone here had posted that they went through all the same replacements and in the end had to have their DME/ECU repaired. I have only found this one case of an ECU gone bad.

I'm at the end of my skill set here.

The car is hard to diagnose because it goes into limp mode at idle right away after the engine is turned on and shuts off all injectors in bank 1.

Other than misfire codes and fuel shut off I got: P050B, P15DF, P137C

P050B: Cold Start Ignition Timing Performance
P15DF MINI Code - Cold Start Fuel Pressure Too Low Bank 1
P137C is a kind of OBD-II Diagnostic P-Powertrain Diagnostic Trouble Code for Citroen Mini-zup.
P137C Citroen Mini-zup is described as Fuel System Too Rich, which basically means bank 1's oxygen sensor has detected a rich condition of fuel. This means there's not enough oxygen in the exhaust from too much fuel being delivered into the air and gas mixture for combustion. This is because the barometric pressure sensor is part of the MAF sensor. Sometimes, the MAF's sensing wire can accumulate and get covered with dirt, dust and/or oil residue, which can also lead to the error code.

There are three possible scenarios:
1. The high pressure fuel sensor is bad and gives a low reading to the ECU, this causes the ECU to dump too much fuel, causing all bank 1 misfires and code P137C (Fuel System Too Rich). I have cleaned the connector but have not swapped them side to side to see if the issue goes to bank 2. That will be my next step.
2. The Variocam is bad, causing bad timing, then misfires, fuel pressure too low, ECU dumps too much fuel, then causing a mixture that is too rich. Here is my question: Is there a specific code I should see if the Variocam is bad?
3. ECU bad

Any help is greatly appreciated.

Thank you.

[M5Rick]

Swap them round and let us know, what year and mileage is it and if any tunes added.

[BlackBear]

It's my tuned 2013 M6 Cab with 55k miles. I have owned it for four years and it received regular maintenance, incl. new plugs and coils every 10k.

[M5Rick]

Of course MAF's should be first thing with spray cleaning with CRC, not much help I'm afraid has it got different air intakes? If misfire has suddenly come on is the gas you filled with bad..I'm just keeping with the basics before taking things apart.

[technician117]

Have you tried checking the connections on the DME for that bank? I'd unplug each one, inspect the pins on both sides and then make sure they get fully seated when reconnecting.

Are you clearing codes each time you swap parts around? I would, just in case you see something different.

[BlackBear]

Thank you for your help.

All great ideas. I will check the pins on the DME.

Yes, codes are reset after every change.

There are some PERMANENT codes. I can't get rid of those. Is that the problem? They don't show up the regular way or in ISTA but do show with a regular scanner as PERMANENT codes.

Originally Posted by technician117

Have you tried checking the connections on the DME for that bank? I'd unplug each one, inspect the pins on both sides and then make sure they get fully seated when reconnecting.

Are you clearing codes each time you swap parts around? I would, just in case you see something different.

[BlackBear]

I have replaced the high pressure fuel sensor now with a new one. After the new one was installed the car idled a LOT better for three minutes, then set a cyl. 4 misfire code. I deleted it. Car idled great for five minutes then threw a lean code for this bank. Cyl. 4 has a new fuel injector and has been flow adjusted in ISTA.

The question now is: Is it the high pressure fuel pump or the DME?

Can the DMEs be switched side to side? The fuel pumps can.

[BlackBear]

All coil packs and plugs had just been replaced. I used yet another new coil pack and plug in cyl. 4. After five minutes of idling and a ten minute test drive there are no codes. Let's see how it holds up.

[M5Rick]

It's a '13 so you put only OEM Bosch coils in..these damn connectors can be hit or miss.

[technician117]

Originally Posted by BlackBear

All coil packs and plugs had just been replaced. I used yet another new coil pack and plug in cyl. 4. After five minutes of idling and a ten minute test drive there are no codes. Let's see how it holds up.

I assume it's still running good?

[M5Missile1]

Check compression on cylinder 1. You might have damaged it.. I went through all of that and turned out I had a bent rod. Good luck

[bwaccord99]

Did this end up fixing your problem? Just going through this same issue after replacing injectors and plugs. now getting misfires and limp home mode... super frustrating.

[BlackBear]

Originally Posted by bwaccord99

Did this end up fixing your problem? Just going through this same issue after replacing injectors and plugs. now getting misfires and limp home mode... super frustrating.

Has been running great after I replaced the high pressure fuel sensor with a new one.

[M5Rick]

Originally Posted by BlackBear

Has been running great after I replaced the high pressure fuel sensor with a new one.

Might be the first thing to check then rather than injectors, coils etc.

[bigbody750]

Originally Posted by BlackBear

Has been running great after I replaced the high pressure fuel sensor with a new one.

Did you get ANY codes related to HPFP? I have a misfire cylinder 1 tagging along with camshaft position sensor (no signal) both are intermittent and permanent (they keep swapping back and forth). This all started when my pcv broke on the way home. Replaced BOTH cuz the other one was on its way out too. It was all 4 misfires on that bank(1), after clearing codes, replacing pcv hoses and plugs annd messing with modules, it became just those 2 codes. Already checked packs, not the packs. I’ve inspected (almost) all vacuum lines visually. Disconnected from pump and put air thru lines, they held pressure. Even plugged (hoses, pump) still ran rough. I took it for a test drive and it builds 0 boost. I can put it to the floor and it doesn’t really move at all. I’m not in limp mode anymore but I still have the drivetrain malfunction. Just narrowing things down. Only other concerning code I get is ZGM, said it’s full lol. Just tryna figure out wtf is going on.

[BMWSauberF1]

Originally Posted by bigbody750

Did you get ANY codes related to HPFP? I have a misfire cylinder 1 tagging along with camshaft position sensor (no signal) both are intermittent and permanent (they keep swapping back and forth). This all started when my pcv broke on the way home. Replaced BOTH cuz the other one was on its way out too. It was all 4 misfires on that bank(1), after clearing codes, replacing pcv hoses and plugs annd messing with modules, it became just those 2 codes. Already checked packs, not the packs. I’ve inspected (almost) all vacuum lines visually. Disconnected from pump and put air thru lines, they held pressure. Even plugged (hoses, pump) still ran rough. I took it for a test drive and it builds 0 boost. I can put it to the floor and it doesn’t really move at all. I’m not in limp mode anymore but I still have the drivetrain malfunction. Just narrowing things down. Only other concerning code I get is ZGM, said it’s full lol. Just tryna figure out wtf is going on.

You have a bad ground you have to make sure to put the bolt back in the wiring loom above the injectors and you have to make sure the bracket for the dme’s is bolted down and the grounds for the dme’s are grounded to the bracket as well