Electrical – Help to Identify this IC chip

sorry this is my first post on this forum. I've spent a fair while combing the internet looking for advice and have not been able to find any information.

The problem:
So I've converted the engine in my bmw e30 to a 6 cylinder engine from a 4 cylinder engine and the tacho for the instrument cluster is reading incorrectly. It is to my knowledge that the signal needs to be multiplied by 3/2 to achieve an accurate result. Originally my plan was to implement some kind of frequency divider to achieve this. However, I found out that the coding plugs for 6 cylinder cars were identical in construction to the 4 cylinder cars and when plugged into a 4 cylinder cluster would provide the desired result.

Unfortunately, these coding plugs are out of production and are very difficult to source. The chip itself consists of one 8 pin IC chip. I've tried searching the model number printed on the top but it returns no results. The chip can be seen below:

My goal is to clone the chip by having a board printed and finding an appropriate IC chip to build the circuit upon. I am looking for advice on how I can identify this IC chip and if someone can identify it whether they can point me in the direction of an off the shelf solution.

Thanks, appreciate it

^^ Here are two images, however, these images show the 4cyl chip and not the 6cyl.

Yeah, I know there's thousands upon thousands of IC's. I was just hoping that someone had come across a similar situation. I've worked on black box circuits in the past and have been able to identify various filters from generating bode plots of the circuits at different frequencies but I'm not sure how to go about this for an IC chip. I was going to start by probing the connections on my car to figure out the inputs and outputs of the chip as well as constant power and ground. I could also look up the original wiring diagrams from BMW in some hope can figure out what each pin does by tracing back its connection. Any other advice on how to go about identifying this IC would be greatly appreciated.

UPDATE

So I managed to get in contact with the seller of the clone chip and he was kind enough to point me in the right direction, really awesome guy. Here's what he said:

The 8 pin IC I used is a microcontroller that acts as a coder – a device that uses a data set for scaling instrument cluster gauges. It is not an analogue signal converter.

Does anyone have any experience with coders for use with analogue guages?