[urq] TR : RE : What causes knock ?

[Buchholz, Steven]

... I would not recommend mounting the transducer anywhere but inside the ECU box ... automotive electrical environments are noisy, and you'd probably create more problems than you'd solve.  

Once you're started down the path to replacing the pressure transducer the slope gets slippery fast!  Why stop with only a 2 bar transducer?  You can get integrated sensors that go to 3 bar and beyond, and the RDH repository contains plenty of information that would allow one to rescale their maps to support operation in that regime ... 

The other comment ... I think it was made before ... when you see overboost there's only one place you need to look ... the wastegate.  The MAC-02 has no way to control manifold pressure ... it just uses it to determine the ignition timing and such.  The problem may be a bad diaphragm, a leak in the line that goes to control the WG ... or a sticky WG.
> 
>  Basically, you can take this transducer board:
>  http://www.sjmautotechnik.com/trouble_shooting/ecupic/ecusens.jpg
>  And mount it in/near your older ECU.  (Nothing says it has to go in the
>  ECU case!)
> 
>  (From: http://www.sjmautotechnik.com/trouble_shooting/pinout.html#otwo)
> 
>  In my case, that seemed kind of silly to me, wrecking up a good MAC11,
> to
>  make a MAC 02 work!  I just switched everything over to the MAC 11
> system.
> 
>  Now I have knock sensing, and ECU frequency valve control of the
> wastegate
>  and the ability to pull codes and do tests.
> 
>  I hope this gives you even more to think about!
> 
... I'd be interested in hearing how one got the knock sensor to bolt on the side of the WX engine!  I've actually been setting myself to go one step beyond ... I've got the wiring harness from an MC-2 car and a MAC-12 ... *two* knock sensors!  Of course there's no place to put either of them on a WX!  :-)

Steve B
San José, CA (USA)