Nistune Forums

Matt wrote:Thats correct on the Hitachi ECUs there is a register which is read which has a bit set to '1' when knock is detected. This is then used to maintain knock counters. I added my own counter which is read via a new consult insturction and then reset. That way the application can read the counts at its leasure without timing critical reads required

I have found most of them on the Hitachi ECUs which are the ones which currently have knock support (except for Z32 which has still escaped me. Might be since its relate to the JECS ECUs and knock circuitry is done differently perhaps?)

I was able to test this by bypassing the knock sensing board and send a square wave signal directly into the chip which takes the signal normally from the board. This then set a bit on the knock register for me to confirm

The Mitsubishi (JECS) ECUs have an imbuilt filter circuit and I am unable to intercept directly. I am also unable to know with the registers I have suspected if they work, since the filter circuitry may be filtering out my attempts to simulate knock with frequency generators

Yes its a nightmare. How far with which code code? There are about 70 different ECU part numbers for nissans that I deal with. Each code base varies (hence so does the disassembly). I've done basic disassembly (maps and consult addresses) on most of them, and then look into it further as required

Some others like Eric (eg Z32 VG30DETT) and Dave (B13 SR20DE etc) from tunercode have done a tear down on a particular ROM image to see how they work in more detail

No one has a complete memory map/address map from what I know. Parts in these ECUs are ASIC (application speciifc interface chip) so many of the registers are not known. Most of my knowledge comes from the basic consult information (reverse engineered from Techtom unit and published by PLMS) and map information (reverse engineered by the Japanese in ROM editor and associated GRID tuning packages). Working out also from patents in addition to the basic information from the maps you can start figuring out what the code is meant to do

There is an interrupt table in the various ECUs and the vectors are used. For example consult runs from the SCI vector, injection code on RB30 runs from the multipurpose ASIC A/D converter interrupt which takes in CAS signals and processes from there. It tends to vary between various ECUs but most of the maps and functionality remains the same which is good

Torque wrote:Hi!

Yes I agree, it's only of cosmetic nature.

Nonetheless you don't want the ECU throwing alerts at you, don't you?

Zuikkis wrote:

Torque wrote:Hi!

Yes I agree, it's only of cosmetic nature.

Nonetheless you don't want the ECU throwing alerts at you, don't you?

But the DTC is easy to kill with DTC Filtering, so it's not really a problem.

Torque wrote:

Matt wrote:Well the R33 and Z32 do use different part # knock sensors

One option is to try a single knock sensor and would be interesting to see if having two sets of knock noise going into one input causes more false positives. I suspect it may not since the amplitudes may be the same, and it will produce a square wave output regardless - but then the knock sensor board may be getting confused also

Z32 ECUs use the same knock sensors as SR20s, so that would be option #2

Hi ...
I always though knock sensors produce some kind of sine wave around 15khz?

PL wrote:Trent - you're a legend!

So you like the Kmon then??!

PL

PL wrote:I reckon the guys over at Jaustech have the Knockbox. I'll have to check. I played with it once but I keep going back to my old insulated condenser mic under the bonnet > amp module > heavy duty-clamp-on-your-head-like-a-mofo headphones....

PL

PL wrote:For sure. Come check it out next time you're in town. I used the chassis ears too - but they suffer from waaaay too much mechanical noise. Result = hopeless. I place the mic so it's totally insulated from the engine - this is the key to its effectiveness.

I actually wrap it in a rag and stuff it under the intake manifold, facing the block. Crude - but very effective. This method was inspired by sticking my head under the bonnet with earmuffs clamped tightly to my head when doing a dyno pull - easy to hear knock when your head's next to the engine. This works great but it's somewhat dangerous and makes it difficult to drive the car at the same time!

It worked so well that Simon got me to build a set for them too. He now uses this all the time! I never did get around to building a nice set for myself. So Simon's got the good set and I'm still using my old prototype. Always the way...

PL