Hi all, first off I'd like to say yes I've searched, and this forum has provided lots of useful info in the past, but can't find the answer to my specific problem this time, and secondly I WILL PROMISE to update you all when I finally find the fault that is bugging the life out of me so that it helps anyone else with the same issue in future....
Now My Problem, please help if you can:- The car is a 2008 C63, and it has been running fine up until a few weeks ago when it seemed to temporarily misfire and lose power sounding like it was only on 7 cylinders. After a damn good thrashing it seemed to come back to life, and all was good for a week or so, then the same thing happened again, but this time it wouldn't go away.
I started by replacing the spark plugs, but when I took the airboxes off, the air filters were absolutely blocked up full of crud, so I replaced them aswell thinking all will be fine, and this will go like stink now....
Much to my dissapointment, when I drove it, it still had the misfire, and sounded off, but worse still, when I floored it, it started misfiring worse than ever, and then generated the check engine light, and shut off fuel injection to about 3 cylinders in order to protect itself.
I got back and put an icarsoft MBII scanner on it, and it showed the following codes:-
'Random Misfire'
'Misfire Cylinder 5 Detected'
'Misfire Cylinder 7 Detected'
'Misfire Cylinder 8 Detected'
Please note, all of these misfires are on bank 2 only (the left hand bank).
Since the fault only occured on the left hand bank, I decided to swap everything (in stages) i.e. Fuel injectors, coil packs, etc from left to right, to see if the fault moves, but the fault is STILL on the left hand bank.
Below is a list of things I have tried so far, and I am at a complete loss, so if you can come up with any help, it would be greatly appreciated:-
1) New air filters
2) New spark plugs (NGK ILZKAR7A10)
3) Cylinder comperssion test (Cylinders 6 and 1 190PSI, the rest all 230PSI)
4) Fuel Injectors swapped from between bank 1 and bank 2
5) Coil packs swapped from between bank 1 and bank 2
6) Ran car with Mass Air Meters disconnected, made no difference
7) Checked live data from Mass Air Meters, Manifold Absolute Pressure Sensor, Intake Air Temperature Sensor, Fuel Rail Pressure Sensor, 02 Sensors, and all OK.
8) Full strip down, inspection, and rebuild of inlet manifold, no leaks or cracks found, and variable intake length mechanism working OK. All reassembled with new gaskets and bolts.
To add further info, I have ran the car up the road while monitoring the fuel trims, and under partial load, while bank 1 (drivers side in the UK) short term fuel trims are going circa 7 positive (adding fuel), bank 2 (faulty bank) short term fuel trims are going circa -15 negative. This is resulting in a lean condition in bank 2, and subsequent misfire, buy WHY?
Mods are exhaust only:- Secondary cat delete replaced by crossover pipe, and resonator delete, and the car has covered at least 3000 miles without a problem since this..
Thanks in advance for your help.
Now My Problem, please help if you can:- The car is a 2008 C63, and it has been running fine up until a few weeks ago when it seemed to temporarily misfire and lose power sounding like it was only on 7 cylinders. After a damn good thrashing it seemed to come back to life, and all was good for a week or so, then the same thing happened again, but this time it wouldn't go away.
I started by replacing the spark plugs, but when I took the airboxes off, the air filters were absolutely blocked up full of crud, so I replaced them aswell thinking all will be fine, and this will go like stink now....
Much to my dissapointment, when I drove it, it still had the misfire, and sounded off, but worse still, when I floored it, it started misfiring worse than ever, and then generated the check engine light, and shut off fuel injection to about 3 cylinders in order to protect itself.
I got back and put an icarsoft MBII scanner on it, and it showed the following codes:-
'Random Misfire'
'Misfire Cylinder 5 Detected'
'Misfire Cylinder 7 Detected'
'Misfire Cylinder 8 Detected'
Please note, all of these misfires are on bank 2 only (the left hand bank).
Since the fault only occured on the left hand bank, I decided to swap everything (in stages) i.e. Fuel injectors, coil packs, etc from left to right, to see if the fault moves, but the fault is STILL on the left hand bank.
Below is a list of things I have tried so far, and I am at a complete loss, so if you can come up with any help, it would be greatly appreciated:-
1) New air filters
2) New spark plugs (NGK ILZKAR7A10)
3) Cylinder comperssion test (Cylinders 6 and 1 190PSI, the rest all 230PSI)
4) Fuel Injectors swapped from between bank 1 and bank 2
5) Coil packs swapped from between bank 1 and bank 2
6) Ran car with Mass Air Meters disconnected, made no difference
7) Checked live data from Mass Air Meters, Manifold Absolute Pressure Sensor, Intake Air Temperature Sensor, Fuel Rail Pressure Sensor, 02 Sensors, and all OK.
8) Full strip down, inspection, and rebuild of inlet manifold, no leaks or cracks found, and variable intake length mechanism working OK. All reassembled with new gaskets and bolts.
To add further info, I have ran the car up the road while monitoring the fuel trims, and under partial load, while bank 1 (drivers side in the UK) short term fuel trims are going circa 7 positive (adding fuel), bank 2 (faulty bank) short term fuel trims are going circa -15 negative. This is resulting in a lean condition in bank 2, and subsequent misfire, buy WHY?
Mods are exhaust only:- Secondary cat delete replaced by crossover pipe, and resonator delete, and the car has covered at least 3000 miles without a problem since this..
Thanks in advance for your help.