Bad ISC on a 1990 Throttle Body

[FouRG63]

I would like to replace it but I have read that 1990's have different TB's than all other years. Can an ISC from another year work?

What about upgrading to a 2g throttle body? I have heard of people doing it, is it a direct swap or do you have to fab stuff for it.

 

[philipkrotch]

i dont understand?? are u saying u have a 1990 and need to replace the isc? in that case no other year but a 90 will work. and what are u talking about by upgrading to a 2g throtthe body? thats downgrading..by about 6mm. post a reply a little more clear so we can understand.

 

[abakja1]

I have a 1990 Mits GSX that was made in May of 1990 (check your driver side door jamb to find when yours was made),..I swapped in a later 90-92 TB and been having problems, but that is just my case only,...But to get to your question,...

Anyways,..if you have a early 90 (May90 or earlier) car, then the TB you have should have 2 vaccum nipples on top and 2 on the front side of the TB,..

If you have a post May 1990 TB then you should have the 4 vacuum nipples on the top of the TB,..

The difference between a 90 TB and later 90-92 TB is the wiring connection for the TPS which is different and not interchangeable (if swapping), and also the shape of the ISC,..The wiring harness though for the ISC/IAC will plug in with no problems,..Also, people are getting the later 90 TB cause they can block off the FIAV and bypass the coolant hoses going to TB,..The early 90 TB can seperate, but the passage to block off with RTV silicone is too large and different in shape compared to later 90 TB,..Other than that, you can bolt on the TB with no problems, just make sure the used TB you get will have no seal leaks, is clean, and has good ISC and TPS sensors and you should be good to go,..

Kevin