Alright I just finished replacing my opti with a MSD unit. Everything works awesome! No compliants from me! I even called MSD up and they sent me one of the newer gaskets for free! The only difference is that the old one is just a regular round O-ring and the new one is square so it doesn't roll of the lip.

Anyway here is where I need you guys help. The MSD opti allows us to vent our units like the newer ones are from the factory. How exactly do I do it? I already have the fresh air inlet in the elbow but where do the other hoses go? So far I have ran it from the opti, up the intake manifold, and where the T connector is I plugged the hose into the vaccum source above the PCV valve. Where does the other hose go? From what I have read is its supposed to splice into the EGR hoses but I don't have EGR since its been removed. The hole above the PCV valve was already plugged when I had to route the vacuum lines from the opti. So would I just need to remove the T-fitting and plug the 1 hose thats left directly on the intake manifold? I just don't know if this will hurt anything?

 

i have a 95 and i have 2 vac hoses going ot the intake manifold. 1 has a check valve or two on it and i think that is the one that runs spark advance, not sure what the other one does put it plugs on the side next to the other one

 

http://www.msdignition.com/pdf/8381_frm27275.pdf

 

Yeah, I guess if you read the instructions, it is pretty clear.

 

I did read the instructions but it says to splice into the hose above the PCV. I didn't have a hose above the PCV because it was plugged with a vacuum cap. So I removed the vacuum cap and put bottom part of the T into that but there is still that 1 hose that points to the firewall? What do I do with that? It has nothing to connect to.

 

Cap it off or switch the tee for a 90 degree vacuum fitting. If you had nothing plugged in before, it would stand to reason that there will be nothing to plug in now. Perhaps someone deleted some emission components and they were plugged in there. That would explain the cap.

 

for the hose going into the manifold i used the 3 way piece that came iwth it and even tho the hose is a 90* one i still shoved it on and havnt had a problem. for the vent supposed to go into the intake elbow i drilled a hole, stuck the plastic fitting in, and used RTV sealant to seal out any air. havnt had any problems with either one and ive had it set up like this for a year and 20,000 miles.

 

Here is what I'm working with:

In this pic you can see everything the way it was from the beginning. Notice the plug above the PCV valve.

Here is the same pic with the brake booster removed so you can see the hoses and holes.

Here is how far I've gotten so far. I got the fresh air hose in the elbow, vacuum hose routed to inake manifold and ended up with this.

Here is a look back so you can see there is nothing to hook the open opti hose to? Also notice the connector on top of the fuel rail. Where does this plug into? I noticed it today while trying to route the opti hose.

 

Um...How about you take the tee out and put the long hose directly on the vacuum fitting???

Frank
CPT

 

There is no "vacuum advance" on an Optispark distributor. There are two connection on the vented Opti (and the MSD unvented Optis) for a vent system. One is the air supply line and runs from the blue plastic elbow in the intake elbow to the Opti, and the other is the vacuum line that runs from the Opti to the driver's side of the intake manifold. If you have two lines running from the Opti to the side of the intake manifold, something is screwed up.

Shoebox has photos of a 95 that make it crystal clear:

http://shbox.com/1/opti_vacuum_hose.jpg

http://shbox.com/1/opti_vacuum_harness.jpg

http://shbox.com/1/opti_vacuum_conn.jpg

To answer the original poster, since you have the EGR vacuum port capped off, you take the vacuum cap off the nipple, and push the Opti vent hose over it. You only need a "tee" if you have all the normal vacuum lines connected.

 

Thats what I thought. I may have not made it clear in the post but I had planned on removing the tee and plugging 1 hose directly on the manifold. Thanks guys!

Lastly what is that plug in for? You can see it in the last pic on top of the fuel rail right above the injector. I found it today while trying to find where to route the hoses.

 

No, that would seem to easy.

Likely for the EGR solenoid you don't have.

 

Alright guys thanks for all the help! I just removed the T-connection and plugged the opti hose directly into the intake manifold.

 

New parts were $15 from GM for me. Last month.