E90 N46 stuck in limp mode

[JacquesBlom]

I am having an issue with my 320i where it is stuck in limp mode. We did have VANOS related errors, so I removed and cleaned the VANOS solenoids.

That fixed the idling issue I've been having for a while. It would idle relative well and then suddenly start idling very lumpy for a bit.

Then a few times, especially when warm, it would not respond when pressing the accelerator to pull away and you had to "pump" the throttle a bit before it responded.

The large "half-engine" warning light came on and it went into limp mode.

But after clearing all the errors it stays in limp mode and he could not find away to get it out of limp mode. I even disconnected the battery for about 8 hours with no success. Still in limp mode.

The big question now is how to get it out of limp mode, without taking it to a stealership.

 

[freakoid9000]

You need to post the fault codes. Otherwise its just a guessing game.

 

[JacquesBlom]

You need to post the fault codes. Otherwise its just a guessing game.

Ok will see if we can get any fault codes out because even after clearing it and no mentionable codes returned it stayed in limp mode

 

[DarrylvanNiekerk]

As mentioned it could be a number of things, you need fault codes to diagnose.

I had a problem with one of the wires of my throttle body and it did exactly what you are describing.

Then again if the MAP is disconnected or faulty it will also not run correctly.

Lots of sensors which when faulty or signal is lost will trigger self protection and it will go into limp mode.

 

[DarrylvanNiekerk]

What mileage is your engine on, what is the maintenance record like?

In my mind if cleaning your solenoids affected your idle then you possibly have bigger problems going on. If the solenoids were blocked to that degree then the oil probably hasn't been changed regularly and you've got gunk build up everywhere or the oil pressure is low meaning the pump is possibly bad due to excessive wear from something running through it or poor maintenance.

The fault could be electrical and solvable by checking connections and maybe replacing a part or two or it could be major engine wear with low oil pressure and the VANOS is unable to properly set valve openings and advance or retard timing.

My suggestion would be to find a mechanic that knows their stuff on that engine, not just to look for fault codes but also to diagnose the whole engine and what it is doing. From MAF through MAP, injection durations, advance or retard of inlet and exhaust, O2 readings and so on.

By looking at the system as a whole you are more likely to find the fault and prevent engine failure rather than just pulling a code and looking for a quick solve as all the engine parts need to work in harmony.

Air fuel ratios being out can cause lumpy idle, so can a vacuum leak, blocked injectors, worn plugs, damaged coils, low fuel pressure, damaged valve cover gasket.

A sudden change or fault can point to an electronic fault but a slow and gradual change with regular gremlins points to a bigger problem.

My two cents.