Some guy told me that their is more than one kind of the PM6 ECU. Is this true? I always thought their was only 1 kind. I'm talking about the 88/91 CRX/Civic Si ECU of course.

 

the 88 is different internally (hence no chips available) the plugs are still the same and they will work in any other year it's just that the internals are physically different. The 89-91 are all exactly the same. So You could say that there are two different types but they all interchange.

 

there are a few different ones if wed like to get all technical......the civic ex did come in automatic trans and uses a pm6 also thus making one besides our everyday pm6...also the 91 pm6 has a higher redline i believe making it a different pm6 also and the pm6 in the 88 crx's no civic pm6 in 88 lke he said is internally different cause mpfi was still changing from vacume advance dizzy to the newer style i assume had to work out bugs in the obd0??? duno for sure ask some japanese guy who designed it all