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MR2/ST205 and Knock

Grant Baker

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Hi Guys,

Anybody using onboard knock on an ST205/MR2 plugin G4+?

Having a few issues with it not actually picking up anything at all on a customer's car. He wired the Knock sensor himself but I've checked and it is correct.

Interestingly the pinout info in the help file does not show a Knock Input, but Link's Tech dept confirmed the pins are as per stock.


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Unfortunately some of our pinouts have become a bit out of date as someone has forgotten to update them when we have made small revisions.  This is one of them.  

I can confirm that the ECU Knock input is definitely connected to pin 42 on the G4+ ST205 plugin.  

Are you using a wideband sensor or the original one?  Freq & gain etc all set up correct?  Firmware newer than 5.4.1?

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Running latest firmware. Freq and Gain all set up by Grant. See attached for typical results. We only see knock on one cylinder...

Should the stock (original) knock sensor work with the G4+ MR2Link V2-3 plugin? If so, ours doesn't. 

We then plugged in a wideband 2 pin sensor, wired up to the ECU (disconnecting the stock knock sensor) and we get the same result.

Then wired a loom in separately to the ECU, same result. Then tried a different wideband sensor and yes you guessed it, same result...


IMG_20170729_151038 (Small).jpg

IMG_20170729_151049 (Small).jpg

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Your above photo shows it is working.

If you are running a distributor ignition system then you dont have the capability of individual cylinder knock control.  As per the help file:



Edited by Adamw
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Hi Adam,

Thanks for putting us straight on that one.

Is it wise to use knock control in this instance or should we change to a COP system?

Can we change to a COP system with the plugin ECU on the ST205 in order to benefit from individual cylinder knock control?


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Knock control is generally used as a safety mechanism to minimise harm if for instance some low octane fuel is put in the tank or the IAT climbs higher than normal due to some problem.  Signal channel knock control will still provide this safety feature.

That ECU is capable of direct spark and ignition outputs 1-4 are available on the main header should you wish to upgrade later.

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  • 2 years later...

Would you guys mind fixing this?  Knock sensing per cylinder is extremely useful for finding issues with particular injectors, ring seal, valve seal, etc. per cylinder.  The ecu appears to be able to trim ignition and fuel per cylinder so why not give us the data per cylinder even with a distributor?

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