I have probably been through about 6 or so optis in the 5 years I have owned the car and the car has been down for probabaly a total of two of those years . It is always due to corrosion in the connector on the body of the opti. The most recent case, I got a used opti that was a clean as the day it was built and put it on my car. Less than two weeks now and Im getting a low resolution failure and the car wont start. Or if it does it runs for about 1 1/2 min and stumbles and then dies as soon as the code is thrown. Ive tried putting dielectric grease on the connector and it doesnt help. I was told by a friend that a loose ground could casue the accelerated corrosion. Could that be it? I have my ground wire from teh battery to the block on the pass side and the one from the frame to the coil bracket on the driv side.
I also read that the high voltage in the opti could be causing it. I am running a Mallory 685 and an MSD coil. I dont know at this point. Could I use that battery spray on the connectors to try and stop the corrosion? Im ready to scrap the whole thing and get an LS1 and get away from this opti. Thanks for the input

 

did you every replace the opti harness?

 

Yes I bought a brand new one from Casper

 

I have a serious problem with corrosion in my opti. So what I was thinking is, instead of have two vaccum sources for the opti, have one vaccum and one pressure to try and circulate air a little better. I was thinking about tapping into the pressure side of my blower and running a valve in-line to limit the amount of pressure it sees and then run the vaccum as normal. Plus I thought little pressure may help the water stay out, kind of like optical sights that are purged with nitrogen. Thoughts??

 

One hose on the vented opti is already manifold vacuum, and the other is filtered, metered, fresh air going into it..
The vacuum line should already have a check valve[more like a 'restrictor' ] in it also..
Interesting idea tho..

 

The fact that there is a blower involved is going to affect the air flow through the Opti, depending where you make the two connections.

As noted above, in the stock setup, there already is an atmospheric pressure air supply line (not a vacuum) from the inlet elbow, and a vacuum line from the intake manifold.

With the blower setup, where do you currently take the air supply line (the one that used to come from the inlet elbow) off the inlet air ducting? Where do you currently have the vacuum line connected - still to the stock location?

 

You have a blower. That means if the Opti air supply and vacuum lines are not hooked up correctly for the blower setup, you could actually be pressuring the Opti and not venting it. If you are pressuring the Opti, there's a good chance you are blowing any moisture in the air, plus the corrosive ozone that forms when the spark discharges in the Opti, right out of the seal on the wiring harness. That would definitely contribute to corrosion.

I saw another post where you were asking about changing the hoses on the Opti. My question is "how do you have the Opti air supply and vacuum lines hooked up now?" because if they aren't right, they are contributing to the problem.

 

Well Injuneer, I have both vaccum lines from the opti tapped into the end of the air filter on the intake of the blower. I assumed that this would be the best source of vaccum seeing as how it will always be sucking in air

 

I never knew that one of the two lines was air going into the opti. I assumed they were both vaccum, one for the cap and one for the sensor Learn something new everyday.

But would there be a vaccum at both hoses under part throttle because you are estab a vaccum that close to the TB

 

If both are on the air filter, then no air is flowing thru the opti.. [they are both at the same source.. there's no 'pressure differential']you need vacuum[manifold vacuum from the intake] and the other on the air filter to get air flow thru the opti..
Not sure how a blower affects vacuum[ there's be less, I would think?] but I still think it would be best to hook one to intake the other near the air filter..
Maybe those that have blowers can add more..

 

It would seem that where you have them placed is not creating any air movement at all since they are both at the same pressure/vacuum level. There must be a differential in pressure to create flow.

The factory vacuum line hook up at the rear connector on the opti goes to the intake elbow between the filter and the TB. The front connection nearest the cap goes to the intake manifold. There is also a restrictor and a check valve in the hose going to the intake manifold. Without the restrictor, the vacuum differential would be too great and possibly do damage to the opti.

We or at least me, would like to see what your corrosion looks like. I would also like to know if you are having a problem internally to the opti with corrosion.

 

Well the cap and rotor are corroding, also the connector for the optical sensor is also corroding. I would take some pics but I have already cleaned it up

 

Vacuum at the throttle body at WOT and max RPM should not be more than ~1"Hg or ~3kPa. At that point, there's little if any difference between the point right in front of the TB and the intake manifold. At closed and part throttle, with little air flow in the inlet ducting to cause pressure loss, you should see essentially atmospheric pressure at the TB.

If you have more vacuum than that at WOT, you have a problem with your air filter or the ducting being too restrictive. And with your blower, you're going to have full boost at both the TB and the intake manifold at WOT.

 

These two threads are essentially duplicates, and have been "merged". Hence, what appears to be similar posts/responses.

 

Just wanted to say thanks guys. I plugged my vaccum guage into the air filter and found out that I wasnt even getting a vaccum with the lines hooked into the air filter. The filter is too big for the blower to create a vaccum in the filter. So what I did is plugged the one line with the restrictor into the intake like from the factory and the other one I stuck in the air filter so it go clean air into the dist. I put my vaccum guage into the line that got plugged into the air filter and I was getting the same 14 inches of vaccum as my boost guage. Thanks again guys and we'll see how long it lasts this time