Oh no, it's the Opti... Or is it???

Getting intermittent error 16 (low res) or 36 (high res) codes. All of everything is brand new. Just broke in the cam on the new stroker. OEM style opti from O'Reilley's, brand new plug wires and coil. New opti came with a new cable (the one that goes from the opti itself to the harness on top of the engine). Codes have popped up both with it and with the old cable. I did have a small water leak at the thermostat gasket that dripped some on the opti before I noticed it and corrected it, I am hoping this didn't kill it.

Codes almost always occur when revving, either in the driveway while data logging or under load while accelerating. Both codes never appear at the same time, and it hasn't died, it just chugs a couple times then has a noticeable decrease in power after the CEL comes on. Everything online says the opti is bad, and if necessary I will pull it and swap it, but it is literally brand new. I read somewhere that if the vent line to the intake elbow is clogged the vacuum line can suck the opti disk into contact with the innards and make it malfunction. Is that a possibility? Can I temporarily remove one or both vent lines to see if the issue stops? I thought about spraying contact cleaner into all of the electrical connectors in case corrosion is causing a bad signal. Is there anything else to check before pulling the water pump off? Right about now I am SOOO glad I removed the mechanical fan system and I can actually see the front of the engine. Can either a bad ICM or PCM cause a 16 or 36?

Forgot to mention, it also has a brand new ignition control module as well. I could swap the original ICM or Opti-spark back in for testing as I haven't thrown either away yet.

If you're getting intermittent codes on both sides, I'd wonder if either the optical sensor is bad or you have intermittent faults on the 5V and ground signals in that harness.

Yes, you can unplug the vent for a bit (just don't drive through rain or puddles), but there's no truth to vacuum sucking the trigger wheel around; it's equally exposed on both sides.

Do you still have your old optispark?

I would go with OEM Opti...

I do have the old optispark that was working when I pulled the engine 5 yrs ago. Is there any point in pulling the vac lines if the story is a myth? Is there any way to check the 5v and ground signals in the harness? I am mostly trying to eliminate all other possible causes before I take the engine apart.

jayoldschool wrote:

I would go with OEM Opti...

At the point when I bought it there were no OEM Optis in the area. I have read reviews on both the Accel and MSDs that reported them not working right out of the box as well, so it seems like a crap shoot no matter which one you get. Is the OEM significantly better than any of the aftermarket ones?

Just cleaned, blew out with compressed air and re-attached all electrical connections, and removed the vac hoses. Took it for a test drive after clearing the codes, and the first acceleration pull set the Hi Res error again, accompanied by CEL and the chug, chug, chug thig again. Gonna pull the opti as soon as it cools off and try the original one from before the rebuild.

***SOLVED***

It WAS, in fact, the Opti. I took apart my original Opti unit lwith the intention of cleaning it and doing the loctite/sealer improvements, and the shaft bushing seemed to have a little play. So I thought maybe the best bet was to take the mechanicals from the new Opti and mesh with the electronics from the old one. Here is what I found when I opened them both up:

The old unit had some oil, a little corrosion, worn cap and rotor contacts, and the previously mentioned shaft play. The new one was shiny and pretty inside but with TWO noticeable problems-

1- There is a round shim that was UNDER the tone ring on my original unit, and on the new one it was ON TOP of the tone ring. Consequently, whereas the old tone ring was centered in the slot of the optical housing, the new tone ring was VERY low, almost touching the bottom of the slot.

2- The upper optical sensor (above the slot) was glued in, but not flat like the old one. It was tipped up noticeably at the front, and was no longer parallel with the optical sensor below the tone ring.

SO, I pulled the optical sensor housing out of the old Opti, installed it on the new one, and moved the shim underneath the tone ring. The ring was now centered between the upper and lower optical sensors in the slot. I then re-assembled with the aforementioned loctite on the rotor retaining screws and a smear of sealant where the outer housing closes up. After reinstalling, I took it out for a drive, and the conditions that would trigger ERR16 or ERR36 before no longer cause issues! WOOHOO!

So, everything in the Opti is like-new other than the optical sensor itself. Hopefully it has another 100k miles to give

It usually is the "new" opti. So many people have reported problems with them. So many more have replaced perfectly good optis when chasing problems..

Good work!

BTW... you don't have to "break in" a roller cam ;-)

Brother, you are good to go on optisparks. And they really are that simple!

Another trick you can do to test optisparks is to depressurize the fuel system (disconnect the fuel pump harness in the back while the car's running). Then shut the car off, hook up the opti you want to test to the 4-pin harness on the passenger side, turn the ignition on, then spin it by hand and listen for the injectors to click. You can very quickly tell if it's working or not.

jayoldschool wrote:

It usually is the "new" opti.  So many people have reported problems with them.  So many more have replaced perfectly good optis when chasing problems..

Good work!

BTW... you don't have to "break in" a roller cam ;-)

It was recommended by the cam manufacturer. Not as long a process as a flat tappet, but it is a very high lift cam and he said to run it in with 1.5 rockers before switching to the 1.6s.