S54 Lambdas causing roughness?

[turk]

Hi guys,

I have been having some issues with the s54. Its not running quite right unfortunately. Its hesitates on acceleration and just isnt ask quick as it should be.

I was wondering, if the lambda sensor could have been screwed back into the wrong downpipes would that cause the engine to run poor?

I notice the part nos are different

Lambda Probe Fixings - BMW parts catalog

some of the fault codes which are comig up are:

6A Brake light switch (off e46, not important)
4F Exhaust temperature sensor (this is like a mini lambda not used)
89 Jet stream pump(not used)
8F E-box-fan (e46 body)
2A vehical speeed signal (wheel speed I think)
87 Vehicle speed signal (same I think)
42 ews ( programmed off)
2b Cooling water outlet temperature sensor (not important)
27 Lambda sensor heating 1 after cat (not used)
28 Lambda sensor heating 2 after cat (not used)

Have tried new maf, idle valve, tps's x 2

Any ideas?

[turk]

no one?

[DanThe]

Has the rev limit been reduced?

I had to wire a pair of resistors in to remove the rear lambda errors although I cant remember if it was causing a running issue

[turk]

the rears are programmed off. And I have just checked and they are in the correct fanimolds..

I have wired the speed signal from the cluster back to the ecu thinking it might be looking for a movement signal ( aparently it presumes you are not moving and limits the revs)

I am about to take it on the motorway and give it a blast.

ps. my diff has turned out to be a 2.93 :s could be why i dont feel fast enough...

[DanThe]

You should pull that diff very easily with that sort of power, E28 LSD job?
If the rear sensors are programmed off is it normal to still have a fault code for them?

[turk]

If the rear sensors are programmed off is it normal to still have a fault code for them

Aparently so...

E28 LSD job

Not Lsd, itsthe original on the car as its a 325e. It pulls off nice enough, its the latter end of 2nd and all of 3rd that lag a bit...

Im gonna see if i can find a short ratio and give that ago. Also must change the gbox oil as its making a strange hum. Lifetime oil my ass

[DanThe]

The engine must have lost some power, I use a 3.15 and there is no issues anywhere, I was thinking about trying a 2.93 as it happens

[turk]

There is definately something not quite right... Rev limiter has started kicking in since the speed signal has given to the dme.

If lambdas are foeked, is there any chance they wouldnt show up on a code check?

[GermanGorilla]

Hi,

If an O2 sensor goes bad the std ECU
does not always show or throw a Code.

Nobody seems to know why.

There has been debate and suggestion
that it can also lead to premature
Head Gasket failure.


Regards,

The Gorilla.

[turk]

Hi,

If an O2 sensor goes bad the std ECU
does not always show or throw a Code.

Nobody seems to know why.

There has been debate and suggestion
that it can also lead to premature
Head Gasket failure.


Regards,

The Gorilla.

I have been considering this. The engine merely needed the prelearnt adaptations clearing off the ecu and it bounced into life, Nice and revvy, but does stall intemittantly when coming to a stop.

We checked all the components on the engine with a proper code reader, and the lambdas, vanos etc all responded well and gave out the expected readings within the correct tollerences.

I am still suspicious of the lambdas not responding adequately tho...

Never knew about the headgasket debate tho, presume its down to overfuelling etc?