Can anyone help e46 328 running problems

[dirtydog100]

hi, ive been trying to repair my friends e46 328
i scanned the car using my ethos, it came up with several codes, after replacing the cam shaftsensor and the thermostat control sensor, i am left with 4 codes..... all of which seem to be related to the lambda sensors codes 227 228 along with two others (cant remember the numbers but related to o2 banks 1-3 or 4-6 deviation or something)

the car starts fine, if i clear the codes it seems to rev freely, but once the light is on it becomes boggy and slow as if its over choking.

i dont want to go through the hastle ofchanging the lambdas if it is something else causing those codes.

any help would be much appreciated, cheers Dan

[wellard]

Hi Dan,sounds like you have an air leak on the intake side,check the air intake boot between the air mass metre and the manifold,the elbow coming off the main pipe to the idle valve splits.Is the o2 sensor fault saying control limit reached, mixture too lean? If so then you have unmetered air getting in. Kevin.

[dirtydog100]

it says something like banks 1-3 4-6 deviation? thanks il check the pipe tomorrow, what normally happens to the running of the car if a lambda sensor is faulty? i know some cars dont drive much different if the lambda is knackered.

[bss325i]

Hi Dan,sounds like you have an air leak on the intake side,check the air intake boot between the air mass metre and the manifold,the elbow coming off the main pipe to the idle valve splits.Is the o2 sensor fault saying control limit reached, mixture too lean? If so then you have unmetered air getting in. Kevin.

This.

[wellard]

Hi Dan,can you get the p codes for the faults?

[dirtydog100]

hi, p0170 and p0173 cheers

[dirtydog100]

dont quote me on those codes, thats just from memory

[wellard]

Hi Dan,those codes are for fuel trim banks 1 and 2.you have unmetred air getting in,do you have access to a smoke tester?
I would check all the pipes on the air intake and to the cyclone valve,it could also be an air mass metre fault.What engine is it M52tu or M54?
There is a rubber breather pipe along the top of the manifold which splits under the plastic cover thats common as well.

[bss325i]

It will be an M52tu if its a 328i/Ci.

[dirtydog100]

ok thanks, il check the pipe under the cover, where is the cyclone valve? ive got a new intake pipe coming as ive only taped it for now.
the car is so slow its almost un-driveable, you can put your foot flat down and it wont make a difference.
its funny because my neighbour's management light has come on, he has a 3l x5, his intake pipe is split but it drives ok
it threw up two of the same fault codes aswell, deviation between llambda sensors.

[bss325i]

The cyclone valve is under the inlet manifold and has a few pipes coming off of it to various places, these can also split and cause problems.

Your symptoms also sound like the cat could be blocked from the monolith breaking up.

Item number 1 is the cyclone valve.

[wellard]

Hi Dan,can you give a full description of the fault,as the other guy says you may have a blocked cat from what you are saying.without seeing and driving the car its hard to diagnose properly!

[dirtydog100]

bit of a break through. we disconnected the MAF sensor and it runs almost perfectly! very strange!

[bss325i]

When you disconnect the MAF, the DME reverts to a default setting.

The MAF meters the air coming into the engine so if there is an air intake leak after the MAF, it will cause running issues as the engine is getting more air than the DME thinks.

I am almost certain you have an air intake leak post MAF. Its verry common on M52's and M54's.