Hi all,

Just registered when I found this article/discussion, finally some quality info! Thanks Andy. I am in Malaysia and the proud owner of a 98 Golf 1.6 AFT engine (Simos S42 ECU) .. 1 of only 112 Volkswagen Golfs of any year registered in this country.. so good info is hard to get locally, to say the least.

Question - I have installed the PerfectPower SMT6 Piggy Back chip, it is currently giving +/- units to Fuelling and Ignition. But as I read your article I am concerned that my piggy back is in contest with the ECU because of the Lambda reading/compensations.. in the scenario where I try to richen the mixture and advance the timing, I suspect the Lambda will be sensing a richer mixture and causing the ECU to lean out the mixture where I have fuel units added , until it runs lean enough again. It may not work exactly like this but ok ... I still have one control function available, and I am starting to think that I should use it on the Lambda circuit to intercept its signal to the ECU. Could you advice a bit from here based on this scenario.

Thanks in advance.

Peace