BMZL1790 Faulty Knock Board??. Help!

[oss96]

Hey guys, pretty new to all this but I think I have a fair understanding of it all.. anyway, as the title says I have a vs hsv manual 185 ecu with the BMZL1790 memcal. Now my drama is, it will constantly log fault 43 (Knock Sensor Circuit Fault)! Knock sensor was checked and replaced anyway, ive pinned out the harness from the bulkhead to the knock sensor plug for continuity .. everything come up fine. I even pulled the sensor out again, and checked the port wasn't covered in rust etc.. The pcm seems to fluctuate voltage from pin b11 (I think it was) constanstly..with the ignition on, engine off, it will reach 4.6v then drop to 0.5v and so on.. is this normal? Start it up and after about 30secs, the CEL comes on with this fault... I Don't know where to go about this, and I'm lost with it.. has anyone had a similar problem? and could it be that the memcal or knockboard is faulty? any help would be great!

[Charlescrown]

Unplug the knock sensor and see if you get around 5 volts at the plug. If you don't get a constant voltage test back at the ECU. If it still gives a funny reading like 0.5 volts it looks like you may have a faulty ECU. You can use a 12 volt to 5 volt USB adapter to supply the 5 volts to see if it works OK. That will then tell you if it's the ECU or something else.

[kojab]

Make sure you have the correct knock sensor fitted, correct one for BMZL has black Socket and measures approx 3.9K ohms. The VT V8 and V6 use white socket knock sensor and measure 100K ohms. Also make sure you have a genuine BMZL memcal with a knock buffer fitted inside the memcal.

[antus]

Im not sure on your history of the car, but if the memcal or knock sensor came in kit form check that you have the right knock board. Its physically on the memcal and you should be able to see the number through one of the inspection windows on the top of the memcal. Its black print on a white board. It should start with 1F. If it doesnt then its a V6 knock board. This often happens with ebay jobs as the genuine V8 knock boards are rare and sellers think they can get away with modifying V6 memcals without changing the knock board.

Edit, yep as above!

[oss96]

Cheers for the help guys, the ecu/memcal come from my old vs clubsport that was hit up the klacker. It has the real deal 1F board in the memcal,
Ahh as to the knock sensor, I got repco to get a new one for me and the one they supplied was a white plug...
I'll have a play around with it tonight when I finish work, and see how I go.. Cheers for the help fellas really appreciate it!

[vlad01]

Well, there's ya problem. White plug ones have an internal resistance of 100k iicr and used on ecotec v6 , the black plug are 40k and used on v6 and v8 from vn up to vs?

So when you use the wrong one you will get a sensor error as the internal resistance is used by the ecu to check if the sensor is connected or not.