97 6SPEED Z

There have been a lot of recent posts on here about optispark failures, so ..... I thought I would post something about my recent Opti experience.

About a month ago I had to replace my "vented" (i.e. '97 Camaro Z - see more car info in sig below) optispark for the fourth(4th) time since I've owned the car. (Car has approximately 84,000 miles on it). After replacing the Opti and getting the car running great again, just for kicks I pulled out the Opti fresh air pick up line going into the air intake elbow, just to see how much air was going through the Opti, while the engine was hot and at idle, (i.e. at high manifold vacuum).

Low and behold .... there was NO air moving through that line. Suspecting that perhaps my twelve(12) year old vacuum harness lines had either collasped or cracked and had begun leaking ..... I replaced all the rubber lines with brand new ones. Still NO air moving through the Opti venting system when, again, I pulled and checked the intake line during hot idle. Now I took off that "quarter sized" blue and white round filter in the Opti vacuum harness ..... and found it totally plugged. I could NOT pass air through it in either direction. At this time I also checked the one way "check" valve in the vacuum harness, but it appeared to be working okay, (it would pass air in one direction, but not the other).

After eliminating the clogged filter, and replacing it with just a straight plastic vacuum line coupler from Autozone, I again restarted the car and checked for air movement through the Opti vacuum harness, and .... it was now just barely perceptable.

Finally, I went further back up the vacuum source "trail" and also pulled out the metal hose "bib" that threads into the side of the intake manifold ..... and found it about 70-80% blocked by gunk. After cleaning this fitting with carb cleaner and a small drill, and then re-assemblying everything .... I finally could feel air moving through the fresh air intake line.

It may just be a small thing but, remember when we put long duration, performance cams with high overlap into our LT1 engines .... the idle vacuum drops quite a bit, and .... I don't think the stock Opti vacuum harness was ever designed to be effective without 17-18 inches of idle vacuum present. Since this little discovery on my part, I've even gone back and opened up (i.e. ported) the metal intake manifold hose "bib" by using a slightly larger drill.

I guess the "moral" to this story is ....... "don't assume that your "vented" optispark is really vented". As the old engineers say, "one test is worth a thousand opinions", sooooo .... do check your Opti vacuum harness for proper operation, because ....... the Opti you save ..... just might be your own.

berakahs

saw your post... wondering what brand of opti is the best??

meissen

Good post - thank you for sharing your experience! I'm going to have a look at my vacuum lines tonight just to check on them.

DugRat

The last time I bought an opti Dal he told me GM won't warranty them any more unless the whole vacuum harness with the filter and check valve are replaced at the same time. The whole harness was only $15.

97 6SPEED Z

Can't honestly say I know what Optispark is "the best", but I went with one from "ThePartsLadi" on Ebay this time around; (based largely on the comments from others on this board). It cost me $260.00 delivered to my door. Allegedly it's an OEM, (now Delphi produced), opti, but the Delphi label does say ...... "Made in Mexico".

Good Luck! with whatever Opti choice you make.

97 6SPEED Z

Considering my recent experience ...... this makes perfect sense.

95Blackhawk

I am going to check mine tonight. Too many failures with only 1K miles averaged on each opti says something.

Additionally, I had lots of rust on my interior metal plate that is on the rotor side (fresh air) so this indicates that the ozone is getting to that side of the opti too easily.

97 6SPEED Z

Yep, after dis-assembling one of my earlier optispark failures I found about two(2) tablespoons of what I'd call "rust dust" inside that failed opti. GM should have made that metal shield out of 304 stainless steel just in case opti circulation was ever compromised. (But then again, considering the size and weight of that metal shield, it would have cost GM probably, another 10 cents in material cost).

mzgp5x

I have modified many vented opti units. The roto usually comes loose from high voltage/ current (so I rivet). Also, I did not like the vent system, so I do not run the gm check and filter since it is highly restrictive to flow. I route to a "clean" area fo air, and I get good air flow with the opti suction line connected to my blower suction side. Any fluid that can be injested by opti can fowl. I am FI so I have had four (4) opti failures. HTH. B.

Venomous360

Ok so off the Larger tube that runs into the side of the intake with the Blue check valve things, should we remove those check valve things?? And where then should we hook this tube??