So my Ruby has 95k rounds on it & still has the original wires & Optispark. The engine from time & the elements was looking a bit grungy, so I decided to power wash the engine bay. I fully intended to replace the opti, water pump, plugs & wires anyway.....in fact, parts are on the way.

With complete disregard, I power washed the heck out of it. I stuck the wand deep into the crevices of the engine bay everywhere I could reach, from the top & the bottom while on the lift.

When I was all done, I used a little compressed air to get rid of the excess water. Then I decided to see if it would start......IT DID!! It ran rough & seemed to clear up as it warmed up. I drove it and it was coughing & sputtering, but continuously improved.

A day later I drove it again & it started fine & ran fine as well. The problem I noticed is that when I attempt to accelerate hard on the highway, the tranny (auto) wont kick down & it acts like the ASR is activating. I can feel the pedal hitting the bottom of my foot the same way.

I am 99% sure that the opti is the culprit here. My guess is that the timing isnt advancing, causing the computer to go into a safe mode, due to engine knock (which I cant actually hear) and not allowing the engine to rev. I dont know if I'm on track here.....any guesses as to what could be going on?

Now, I'm not extremely concerned because my new optispark will be installed when I get it. I'm just curious. The car starts, runs and is basically ok, with the exception of an exhaust backfire once in a while.....I noticed also, when making right hand turns,the engine stumbles & misses. (water sloshing around in the opti???)

I am really surprisd that the car even runs, much less is pretty drivable. I think maybe the optispark gets a bad rap.....this one has 95k miles on it & took a good bath & still starts the engine & runs fairly ok.

discuss..

The computer is not going into safe mode... that's a given. However, the Opti is more than likely not retarding timing as it should.

Also, you may need to adjust the TV cable. It's a bit abstract and requires a torque wrench...

The exhaust backfire is rather common on the early LT1. My 92 did it until I put the LTCC system onboard. Even then, it still does it from time to time.

When you get the opti wet from the outside like you did, you simply soaked the wires. Which is no different than any other distributor. 99% of the time, that kind of cause effect will be just as you are experiencing. However, a year from now, the internals of the opti would start to deteriorate by the water inside the unit... that leads to other problems outlined below.

There are two failure points of the opti:

1. Cap/rotor. This is carbon tracing. It's just like what happens to conventional distributors. Cap gets wet, arcing occurs, carbon build on contacts. Because the opti is so accurate, it is constantly compensating for the misses caused by the carbon build up. The carbon causes a missfire, the computer detects same, engine retarts timing, idle fluctuates and the missfire goes away. Computer adjusts back, missfires again, and the cycle continues.

The bad cap/rotor will also cause a high RPM miss.

2. Codes. These are easily quantifyable. The opti screws up and fires one of two codes, H16 (low res or fuel) and/or H36 (high res or timing). The opti is managing both timing and fuel delivery, one screws up, things stop working right. There are only 2 ways these codes can occur, either the opti caused them or the harness to the opti caused them. That's it. I have actually been told by "professional" mechanics that these codes can be triggered by other faulty components... the Helm manual says it's impossible, too. Or, I haven't found it yet.

Finally, when you get the new opti, if you got OEM, then take the cap off and put a bead of silicone (I suggest copper, it's more resistant to oil and heat) where the cap and body meet. If you got MSD, simply put a smeer on the top of the opti, where coolant from the waterpump can drip.

Also, you can put a nipple and line on the bottom of the waterpump to route the drip away.

Your '95 is vented, meaning it hooked up to engine vacuum to clean out any (most) of the moisture that collects in it.

An optispark is a distriutor.

Would you take a garden hose to a regular distributor and expect it to run right w/o having to remove the cap and get all the moisture out?

his has 95k, IIRC, it's a 93 ruby he is referring to.

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Bogus, that's interesting. When are you getting the backfire? On long deceleration?
I had some small backfiring (multiple backfires) on decel after I put on the chambered catbacks. I found a small leak at the X pipe, switched clamps and now it doesn't backfire at all. Everything's stock except the MSD.

On deaccel.

GM actually issued a TSB for the early 92 units.

It was associated with timing issues of some sort, IIRC.

Thanks B, I'll pull up the TSB. I don't think mine's an "early", 18929.

I wash my engine all the time, and havent had an issue with the distributor. Its on its second cap and rotor, but the unit is original. Its not vented.

i get backfire out the exhaust when the ASR kicks in under hard acceleration.