S52B32 ECU wiring/lambda info

[DanThe]

Hoping some of you guys can help me out a bit with my conversion, its an Alpina B3 3.2 engine and im trying to run it on an S52B32 ECU, it should be running an Alpina ECU but it didnt come with one and they are nearly £2000 to buy from Alpina so I thought id try an S52 brain first :)

The problems im having is it keeps giving fault codes for secondary O2 sensors and as a result its drinking fuel like its going out of fashion, so much in fact it will barely run at idle.
Now the Alpina only ever had 2 lambdas up front in the manifolds, but as the S52 is a US engine im thinking it might need to see 4 lambda signals due to your stricter emissions rules, does this sound right? Is there a way to run with only 2 lambda sensors?
As the fault code is "O2 sensor heating, open or short circuit" can I trick the ECU by giving it a circuit for the heating, or will it need to see the values from the secondary sensors also?

Hopefully someone will know what im on about :)
Heres a quick pic of where im at

[matt]

I know exactly what you're talking about.

Are you running a US spec S52 ECU? Marked: MS41.1 / 1406464?

[DanThe]

Yes, its an MS41.1 from a US Z3M

[DanThe]

Does anybody have a pdf or a link to an engine wiring diagram?

[surebimmer]

http://wedophones.com/BMWManualsLead.htm

[hoveringuy]

How is the Alpina B3 different from a US S52?

[328ijunkie]

What gives you the impression thats an alpina motor?
Looks like an M52 with a shrick intake mani

[DanThe]

Thanks for the link 8)

What gives you the impression thats an alpina motor?
Looks like an M52 with a shrick intake mani

The inlet manifold sort of gives it away :)



Ive never seen am S52 up close but im assuming it is very similar

[DanThe]

Does anybody do a cat delete on these? Im just wondering if the second set of lambda's needs to be giving a different output signal to the ECU, less O2, for the ECU to stay happy.
I dont need cats on my car so maybe wiring in a second set of lambda's would be pointless anyway

[Adrian_Visser]

I would shoot a pm to the first person to respond to your thread (matt from trm) He has the means to reflash your DME to delete the secondary O2 sensors, I think that is really the only way to get rid of them. The other option would be to install them and wire them up.

[matt]

You have a couple issues going on. I may be able to help. I would prefer an email to matt@racersmarket.net

Thanks,

[DanThe]

Lambda faults have been dealt with, I wired a pair of resistors into the post cat lambda circuit to fool the ECU into thinking it is pulling current for O2 heaters,



engine pulls sweet all the way up to 7k revs 8) Only niggle is it doesnt want to idle smoothly, not really hunting, but like its about to cut out. I have no fault codes now, im using an M52B28 MAF just like the S52 uses, pink injectors, M52 ICV, everything S52 really so this is quite baffling :???:

Matt, email sent, thanks

[matt]

That will fix the lambda sensor heating errors, but you will still get "lambda sensor no activity" or catalyst efficiency or some other codes if you don't have real sensors plugged in. I'm actually going through this right now for a customer here in the US. You take care of one code, the next one pops up. There is no universal switch for "no more rear O2 sensors" atleast not that I've found yet.

On the idle thing, that could be an issue relating to the intake manifold or cams or any number of other things. Have you checked for vacuum leaks?

[DanThe]

But wouldnt the best signal for the ECU on post cat lambdas be no signal, ie no O2, to show the cats are working properly? Im not getting anymore codes, ive done about 20 miles, maybe I need to drive it more.

Cant find any air leaks, can the idle be made better with mapping Matt?

[matt]

Yeah, it's probably possible to tune it to be better. Or possible to raise the idle speed and just cover up the problem.