ECU question

[rkharton]

I tried to install a performance chip in my 1991 325i bmw and I messed up the ecu, its model number was 0-261-200-525 so I bought another ecu with a model number of 0-261-200-173 and has a stock chip in it, but its running better. What I want to know is WHY???? I know its not a bad thing but this info will help me figure out what type of performance chip to buy and so forth. Oh and I'm new to the site just fyi. So any input would be great, thanks.

[Numark318i]

might be running better because all the soldering is good.

From what i understand the ECU's from E30 have weak soldering and they can crack or just come apart, causing issues obviously.

I know my E30 has an issue with its ECU because intermittently it wont start or idles weird. I tap the dash near the ECU and itll work again. This happend before and after i installed a performance chip.

Atleast thats what a BMW mechanic told me.

So obviously you got a good ECU

[TOMMYSPANNER]

Make Sure The Ecu Has Good Mounting Earth To Frame Or You Could Get These Problems I Had Them Making Me Think The (brain) Was Dodgy