obd1, obd2 ??? ISV placement for what years??

[tdub88]

Recently purchased mk2 jetta with 2.0L 8V swap. Crossflow intake manifold. ABA stamped on the block. my questions are as follows. what is the difference between obd1 and obd2 and how can you tell from looking at the engine. next is i noticed my ISV is mounted to the drivers side of the upper intake manifold and has a tube connecting it to the intake. alot of pics i see do not have the ISV mounted here. as a matter of fact i dont see it anywhere in the pics alot of the time. what gives?? supposedly the swap is out of a 96 jetta. is there any way for me to tell? please help this is racking my every thoughts!!

[Checkers]

From the Whoretex.

if there is an ISV (idle stabilization valve) on the right hand side of the intake manifold, right above the exhaust downpipe then it is an OBD-1. Alternately you can pull the ECU and look at the type of chip that is in it. rectangle=obd-1, square=obd-2

[tdub88]

THANK YOU SIR. just happened upon this site but will post more. and pics. oh yeah the jetta. 88 2.slow swap, 91 corrado brake upgrade to disk all the way around, soon to be custom intake, eibach springs, 3inch stainless from manifold back to ??? muffler(too loud really). this is my "family sport car". lol

[MT-Getto]

OBD2 does not have an ISV. Instead you will have a large apparatus on the throttle body that acts as an ISV.

[sneakyboy1]

Welcome to the site all the way from KY!!!

[kompressorgolf]

Greeting from MonTucky