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+---- Thread: Misfire cylinder 5, about to pull open engine as last resort! (/showthread.php?tid=28393)
RE: Misfire cylinder 5, about to pull open engine as last resort! - Node - 10-10-2017
I would bet on faulty lambda sensor. Especially when misfire "travels" between cylinders. Have a look at adjustment values between banks. If they differ much, that is a flag for lambda.
RE: Misfire cylinder 5, about to pull open engine as last resort! - willisodhiambo - 11-10-2017
(10-10-2017, 14:22 PM)Node Wrote: I would bet on faulty lambda sensor. Especially when misfire "travels" between cylinders. Have a look at adjustment values between banks. If they differ much, that is a flag for lambda.
Disconnected them and test drove. Same misfire, same cylinder, now cylinder 4.
RE: Misfire cylinder 5, about to pull open engine as last resort! - Node - 11-10-2017
Disconnecting them when adaptation values are wrong is not the best idea. I suspect that last stored values are used. Clearing adaptation values and then disconnecting is also not very wise. Is it that difficult to look at values before doing stupid things?
RE: Misfire cylinder 5, about to pull open engine as last resort! - raduandrei82 - 11-10-2017
Had same misfires on E60 N52 engine because of lambda sensors that did not throw any error. Check the values , doesn't matter if the engine si cold or hot, the BMW lambda sensors have 4 wires and they work all the time regardless of engine/exhaust temperature.
Believe it or not, i had one pre-cat lambda with stupid values (it was not dead, just giving bad values) and the car ran like the engine was totally wrecked: rattling, smoke, bad misfires (sometimes i couldn't even accelerate to reach the parking) - all happening at high RPM. I did like you, before checking values: changed cam cover, coils, plugs, vanos solenoids and nothing changed until i replaced the faulty lambda sensors.
RE: Misfire cylinder 5, about to pull open engine as last resort! - willisodhiambo - 12-10-2017
(11-10-2017, 06:44 AM)Node Wrote: Disconnecting them when adaptation values are wrong is not the best idea. I suspect that last stored values are used. Clearing adaptation values and then disconnecting is also not very wise. Is it that difficult to look at values before doing stupid things?
I wouldn't say stupid things. We are DIY enthusiasts and learning as we go along, not professionals. I am open to your guidance on how to test them properly. I suspect we need to go to DME->component triggering and look for oxygen sensor. Target values appears to be between 0.9 to 1.1 as per ISTA.
If possible will run diagnostics while driving as well to see how they perform. Would that be a better approach?
RE: Misfire cylinder 5, about to pull open engine as last resort! - karpiaavi - 12-10-2017
X5 that came to my work plase , roughf idle, no power, no 4wd,.. opened the dde ecu and there was not a single connection that was not corroded.. there was like 10 cm of water on the bottom of e-box..
RE: Misfire cylinder 5, about to pull open engine as last resort! - Node - 12-10-2017
Well, pulling engine apart until you tried every other thing is stupid in my book
You need to go to ecu and see the values. I can't tell you how those values are called exactly because that differs between DMEs and it was some time time ago I did diagnostics on any petrol engine. Can you post screenshots of what values you have looked at? As I remember there should be at least 3 values per bank.
RE: Misfire cylinder 5, about to pull open engine as last resort! - willisodhiambo - 12-10-2017
(12-10-2017, 07:08 AM)Node Wrote: Well, pulling engine apart until you tried every other thing is stupid in my book
Agreed, will record these and share later on. Engine not pulled out yet precisely because I also feel we have not exhausted all the possible things that can cause a misfire. The peculiarity here though is that it is a single cylinder that seems affected which is what is leading us toward DME or cylinder head gasket.
RE: Misfire cylinder 5, about to pull open engine as last resort! - kregiel - 12-10-2017
I have similar problem on N46, was misfire on 4 cylinder and only this one when i disconect any sensor from valvetronic, engine works perfect the problem was eccentricshaft. Did You check rough on every cylinder ? please write correction. In my situation corection was very high.
Best Regards
RE: Misfire cylinder 5, about to pull open engine as last resort! - willisodhiambo - 13-10-2017
(12-10-2017, 12:19 PM)kregiel Wrote: I have similar problem on N46, was misfire on 4 cylinder and only this one when i disconect any sensor from valvetronic, engine works perfect the problem was eccentricshaft. Did You check rough on every cylinder ? please write correction. In my situation corection was very high.
Best Regards
Will test and report. Thanks.