converting from old style opti to new style opti.
Thread Starter
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
converting from old style opti to new style opti.
I have installed a hot cam, cloyes double roller chain set, and the newer style cover on my 93. Can someone tell me where to connect the 2 vacuum lines at? Also, does the new electrical harness have to be repinned? It looks like it will plug in up by the manifold, but it seems to me someone once said it needs a different pin configuration. Course, I could be wrong. Thanks for your help.
Large Impressive Member
Joined: Jul 2003
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Re: converting from old style opti to new style opti. (93 ragtop)
The larger of the two fittings on the opti is stepped down with a reducer nipple, then runs to a manifold vacuum port. There are a couple of diaphragms inline close to where it hooks into the intake. I believe one reduces the strength of the vacuum signal and the other acts as a check valve. Either way, you'll have to get these, probably from a dealer, and make sure they're installed in the right direction. The other one hooks into the air intake to draw clean air for the system. I believe some people have run this one to inside the car and installed some type of filter to draw the driest air possible. You can also get this harness already made up from the dealer. I have heard there's a difference in the wiring too but don't know since mine's a 95 and so wasn't an issue when I replaced mine. I think there's a tech tip on this conversion as well. Hope this helps.
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Re: converting from old style opti to new style opti. (Corvette Kid NC)
Order GM part 12556174 - harness.
one end attaches to the intake, in front of the throttle body, the other, you have to attach to the intake for vacuum. I think the harness is labled for fresh air/vacuum.
there is a wiring difference, but gee, I think that only effects 1992 versions.
one end attaches to the intake, in front of the throttle body, the other, you have to attach to the intake for vacuum. I think the harness is labled for fresh air/vacuum.
there is a wiring difference, but gee, I think that only effects 1992 versions.
Melting Slicks
Joined: Sep 2000
Posts: 2,710
Likes: 1
From: Green Bay WI
Re: converting from old style opti to new style opti. (93 ragtop)
I have installed a hot cam, cloyes double roller chain set, and the newer style cover on my 93. Can someone tell me where to connect the 2 vacuum lines at? Also, does the new electrical harness have to be repinned? It looks like it will plug in up by the manifold, but it seems to me someone once said it needs a different pin configuration. Course, I could be wrong. Thanks for your help.
Poke a small hole in the air intake duct and put the gray fitting into this hole.
You'll have to tap into a vacuum location on the intake for the other tube. There was a post not too long ago showing a possible location - you can probably find it by doing a search. Just make sure that the check valve is on the end where you tap into the intake.
If you have the wiring harness (P/N 12130319) it should plug right in (according to Jeff K at Superior Chevrolet).
Good luck!
:cheers:
[Modified by cprgmr, 9:14 AM 3/6/2004]
[Modified by cprgmr, 9:15 AM 3/6/2004]
Melting Slicks
Joined: Sep 2000
Posts: 2,710
Likes: 1
From: Green Bay WI
Re: converting from old style opti to new style opti. (93 ragtop)
Hey bud - enable your instant messaging in your profile. I have a tip for you that will make this job a lot easier! :cheers:
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Thread Starter
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
Re: converting from old style opti to new style opti. (cprgmr)
Hey bud - enable your instant messaging in your profile. I have a tip for you that will make this job a lot easier! :cheers:
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Re: converting from old style opti to new style opti. (93 ragtop)
Hey bud - enable your instant messaging in your profile. I have a tip for you that will make this job a lot easier! :cheers:
OK, did that. Sorry I didnt get back to anyone yesterday, I spent 13 hrs. in the garage. The problem with the harness hook up is there is a small piece of plastic in the new one that is used to only allow the plug to go on one way. Well it is made different then the orig. plug. So, what I did was take my dremel tool and grind it out of there. I was concerned about the wiring matching up as well. The colors are different, however the letters are the same. Bottom line, it did work as wired. I still have to tie the vacuum lines in. But I would like to say thanks to everyone for their suggestions and help.
OK, did that. Sorry I didnt get back to anyone yesterday, I spent 13 hrs. in the garage. The problem with the harness hook up is there is a small piece of plastic in the new one that is used to only allow the plug to go on one way. Well it is made different then the orig. plug. So, what I did was take my dremel tool and grind it out of there. I was concerned about the wiring matching up as well. The colors are different, however the letters are the same. Bottom line, it did work as wired. I still have to tie the vacuum lines in. But I would like to say thanks to everyone for their suggestions and help.
