MikeC4

This is what I found when I opened up my failing Optispark on my '94 LT1. This Opti was working at the time of removal, however I had symtoms of Lurching at idle and irratic acceleration. I stopped driving the car 2 days after these symptoms appeared, especially when I noticed that they were getting worse very quickly. This was the original Opti. One thing I forgot to mention in the pic is that all the inverse torx bolts that hold this thing together were almost finger tight.....

De-gutted Optispark:


And here is a close up of the optical wheel and Mitsubishi Optical sensor.


And here is the WP bearings that led to this whole mess :

ROB502

WOW my 92 with 97K probably looks worse and I just keep on trucking.

Redeasysport

Typical. Actually that is a bushing not bearings and is one source of ingress.That is one thing the Dynaspark and MSD changed to bearings. From the rust and moisture your sensor probably had a coating on it too. The nitrite seal is a known weak spot too which is why I always suggest a good bead of sealer around the cap.I bet it failed because the sensor is blind.You also see the crappy seal around where the plug goes through the cover here too.

One other thing to look for is "carbon tracing" on the top of the optical sensor plastic cover Once that occurs it will misfire it may be hard to see but the firing may cross over due to HEI following the trace. One reason that just changing cap and rotor may not help as the sensor cover does not come with them and if traced will still miss.

94admiralblue94

[QUOTE=MikeC4;1566572994]This is what I found when I opened up my failing Optispark on my '94 LT1. This Opti was working at the time of removal, however I had symtoms of Lurching at idle and irratic acceleration. I stopped driving the car 2 days after these symptoms appeared, especially when I noticed that they were getting worse very quickly. This was the original Opti. One thing I forgot to mention in the pic is that all the inverse torx bolts that hold this thing together were almost finger tight.....

Can you please explain your "lurching at idle"?

Do you mean your tach would go up and down 50-100 rpm while stopped and in gear?

Thanks

MikeC4

Yes, the RPM's would jump 100-200 and it was like the car was momentarily accelerating. When I was at a stop, I made sure I had more than normal pressure on the brake pedal....The car would ...like....jump. Same thing if car was in Park or Drive.

Also, on exiting the car, a faint smell of coolant led me down the path to the Opti, as no error codes were set....

schrade

Interesting.

If it was mine, I would put compressed air to it and reassemble it (and a nylon toothbrush on the metallic parts). I imagine it could be used for testing since no parts of it look wasted. If it has a bushing, and not bearings, I wouldn't even think twice about it...

My

BrianCunningham

My cap & rotor looked about like that @ 110k

No rust though, factory venting.

I just replaced the cap & rotor.

I bought an MSD for the blower motor.

Rathbone

I started seeing these symptoms today. The car has only 41,000 miles on it and I know I've never got the optispark wet. I guess a waterpump can go bad that fast.

reoch999

Wow, I lucked out. My water pump was just starting to drip from the weep hole, and when I openned up the opti to replace the cap & rotor, the seal was cracked and crumbled in my hand but the insides had no rust, corrosion, or visible damage of any kind. The cap showed its age where the rotor makes contact (don't recall the name for those little metal contacts), but it was not as bad as I expected it to be. Especially since it was not vented. I must have caught it in time.

Mojave

Pshh, that opti doesn't look too bad. This is a bad opti:



No more rotor problems for me; I'm running LTCC conversion with LS1 coils.

dlmeyers

Well done diagnosis. An yup Mohave, that is one ugly opti.

corvette-pilot

how did you get it apart?
I replaced mine last year and got the cap off but not sure how to get into the guts??

jimg's'93

Once you get the cap off you remove 2 screws holding the rotor in place. That done, the assembly just comes apart. Mine looked pretty bad too. My rotor bearing was so bad it 'rocked'. There was obvious wear on the 4 of the electrodes from the rotor brushing against them. No idea how it was even working! And there was evidence that at one time there was a cap gasket that pretty much had disintegrated.

I'm thinking I may turn my old opti into a clock for laughs.

Rathbone

The symptoms I had on Thursday were gone on Friday. Maybe the fuel pump is going out or something.

theadmiral94

MikeC4,

Thanks for the pictures and analysis/symptoms, very nicely done -- will remember this for if/when needed.

Not to get a thread on which is better, but since your like me and do alot of analysis -- what OPTI have you decided to install (oem, msd, etc), vented upgraded?, and from where?

skybolt31

lt14life

Hello, Ok I had the same issues and of course the lurching , So I decided to go with the vented MSD Opti and a brand new waterpump. 20,000 Miles later no problems at all. also I have nothing good to say about OEM Optis that should have been a GM Recall part.