I usually leave the key in the on position so the HVAC blower will blow when at the car wash to help prevent water from leaking through the vert weatherstrips. It seems in the past that wirdness happenbs when I do this and go to start the motor.

Today the motor started fine then as I was pulling out, it died. Was hard to start but started. Died again then started hard again. I hammered on it in first gear and at 5K RPM the engine just totally lost all power and fell on its face and the tach went to zero. I got out of the gas and it returned to normal. After all this I had a code 16.

I then pulled the PCM fuse to reset the DTC code and drove it hard again. I hit 5K RPM and felt a very slight hesitation. After beating on it some more with several 6K RPM blasts in first, its not losing power or doing anything wierd at all. Maybe its a fluke.

Car idles great and runs great except for this incident. Opti has about 10K on it.

Question.
Is it normal for opti wirdness to happen if you leave the key in the on position for several minutes then try to start the car? Does this definitely sound like an opti related issue?

Question 2
Is this definitely an Opti problem? Fuel pressure is spot on.

 

id say your opti is toast. my did the same thing. ran fine but if ud get into it a little the it would cut out and the tack would flicker. a cheap scanner didnt pick it up and i used my friends good one and came up with p36 high resolution failure wich is the sensor in the opti so i put a new one on and no problems.

 

Low res pulses not coming through right... Sounds like moisture rather than anything else. You have a vented opti, so the undercarriage sprayer wouldn't have shot water in the bottom like a 93-94 would be vulnerable to. However, the opti pigtail goes a lot deeper on the pin drive dist. My guess is you got a tiny bit of water intrusion through the pigtail/ connector. Then when you spun it good and hard it vaporized the water enough to vent it out/ dry it.

 

This was a wand car wash so no chance of the opti getting wet. But now that I recall I did wash the motor several weeks ago and tried to avoid getting water near the opti but thats hard to do. Maybe it is lingering moisture from then. I will pull the pigtail and blow it out and lube it up.

Hopefully it blew the moisture out once the motor got hot and its just a fluke.

 

i had the same thing happen to me last fall just before i put it in storage. wand hand wash, stayed out of the engine bay but some moisture must have gotten in there... started it then it jumped in the rpm and died, started it back up, revved it a few times, let it sit, started it, ran fine. not a problem since. i learned to hand wash . not sure if i got water in my intake or the opti, but like i said, i learned pressure washes can go to hell with lt1's.

 

I pulled the connection from the opti and it was either lightly corroded or the dilectric grease hardened up and casused the connection to be dirty. Well see tomorrow how it does.

 

Let me ask again. Is there a thread, or any interest on what actually dies in the Optispark? According to what's going on here every one of these must drop dead every time it rains. Sounds more like an early 50's Nash

Reminds me of the old Mallory Unilite BS that 99% of was not true.

Al

 

My 1995 Z28 went over 100k on the original opti and my brothers went like 110k in his 1993. They aren't THAT bad, but I'd prefer a different setup. I have a receipt for my Trans Am that shows the dealership changed the opti at 65,000 miles because it was "sluggish". They were nice enough to change the coil and module as well....all in all she paid $1200 for an oil change, opti, coil, and module.

 

The optical sensor that reads the 360* pulses gets moisture in it and no longer can read properly. Generally if a vented opti gets moisture in it, within a few miles of warm/dry driving the opti's housing is literally sucked dry. now the non vented didn't have anything to circulate air causing the moisture to linger and keep the sensor working improperly. If a person has a vented opti on their car and can't keep one for a least 15k miles is either revving it to 7000 at every stop light, or likes to splash in puddles. lol

 

Like said above the main issue is with water affecting the optical sensor. Sometimes it can cause the rotor to rust too but that could be said about any distributor. The issues are real but yeah they are FAR exaggerated for the most part I think. Generally speaking as long as you don't just absolutely soak it with water you'll be fine. The possible exception being the 93-94 non vented optis which really are pretty susceptible to moisture issues.

 

that optical sensor is also known for the LEDs that "shines" through the shutter wheel to go out.

 

http://www.youtube.com/watch?v=lFCjaz6zHfc

the training video we had at the "stealer"ship

 

There are 2 designs, many manufacturers, lots of permutations of problems that come from these distributors, but only a small number of root causes. The optical sensor, like all solid state electronics has only a finite life in the presence of persistent heat. Hats off to the Mitsibishi engineers that created the J924 encoder. It lasts a lot longer than you'd expect in probably tens of thousands of heat cycles, sometimes as long as 15 years in extreme cases. Ask your VCR to live that long in your living room...

Most folks hit a problem that prompts them to expend the labor getting to it and justify a replacement because of the effort. Fouling of water, coolant or oil are the most common reason folks tear it down and replace it. I've seen oil intrusion by the rotor shaft due to a bad or improperly installed seal in the timing cover on both types (vented/non). I've also seen coolant getting in through the seals on the distributor body (water pump leaking on it). Also common to get water intrusion similarly by washing the engine bay, driving through heavy standing water (93-94 cars with the weep holes). I had one go bad by crumbling the shaft bearing and clogging the encoder. If the shutter wheel gets bent enough to touch the body of the encoder, it will create enough heat on the encoder to fry it in a couple of days.

In these cases, the optical encoder isn't to blame and would probably be fine for a lot longer if you could correct the physical cause that 'blinded' it. Problem is, nobody makes a rebuild kit for these. And the internal parts rust and can litter the encoder/shutter wheel interface naturally with age. Cheap knock-offs using imitation encoders may work pretty well for a while. Only time will tell who makes one approching the quality of the Mitsubishi. In the meantime, the normal attrition of intrusion/corrosion will continue to cause the vast majority of problems seen with the opti, regardless of where it came from.

 

I have a couple of quick questions.
Can I put a vented opti in my 94?
What is the best way to clean a lt1?

 

1) yes, but you need to switch to a 95 timing cover, change to a dowel pin drive camshaft. ---OR--- use a little ingenuity of your own. Make or pull a vacuum harness from the boneyard, vent the cap yourself with some RTV & vacuum fittings. Here's what inspired my mod: http://www.corvettefever.com/howto/16758/index.html. I decided to put one of my fittings up top for better cross flow.

2) By hand, using as little water as necessary. This really goes for any engine. Pressure washing one just isn't wise anytime.

 

Well the opti lives and is showing no more ill effects. Damn things are just temperamental weird I guess. Ran strong at the track.