Bought a '94 auto in January with 122K miles on it. Have been driving it pretty much every day for work , about 22 miles round trip. Couple little issues, but nothing major. Until a few weeks ago, it stalled on me when I gave it some gas. Pulled over, waited a minute, and it restarted and drove home fine. About a week later, stalled again during coast at 35 mph. Same thing; just shuts off, like key has been turned off. Waited a minute, restarted fine and drove to work with no problem. Stalled once on drive home. Reviewing forums had led me to believe it may be an ICM. So I replaced ICM and ignition coil with new AC Delco parts. Old parts appeared to be factory GM as well. Car actually felt more powerful on drive home from work, but still stalled once on 11 mile trip.
So, my next venture is the Opti. I have new AC Delco spark plugs, wires, and wire retainers to install, a starter switch, and I want to do water pump as well. If it is necessary to strip everything from front of motor, I'd like to reseal timing cover and anything else necessary also. So, I'm putting a parts list of what I need together now. What else is recommended to change while I'm in there? So far on list I have:
-Opti spark unit
-vented cap
-vent hose kit
-water pump and seals
-timing cover gasket set

Lemme know what I'm missing! Thanks all

 

Has anybody actually diagnosed the cause of the fault? It isn't necessary to throw random parts at these cars in order to solve problems.

Live well,

SJW

 

Have you checked the fuel pressure to make sure that it's not a clogged fuel filter or the fuel pump going out?
You don't want to replace the opti unless it's been truly diagnosed as the problem. It can also get expensive throwing parts at the engine.

 

Look for the color of the front of the opti. If it is peanut butter color it is original and you will be WAY better off having the optidoctor rebuild it. Also, if the timing cover is not leaking I would leave it alone. Dan

 

https://www.ebay.com/i/143342861543?...BoCR2kQAvD_BwE

If you do the water pump oil seal you really should also get the tool.

 

Thanks for the responses.
I can tolerate a lot of problems in a vehicle, but stalling is not one of them. Years ago, I was inches from death when a motorcycle stalled on me at an extremely inopportune time on the parkway. This is a 26 year old vehicle; I do not mind spending money on peace of mind knowing that these delicate electronic components are new and reliable. I had already intended to freshen up the ignition system before this problem, with AC Delco where available. Also, my current Opti has a black cap, so I doubt it is original. Any replacement I obtain will be a good name brand, or preferably, a rebuilt original unit with the Mitsubishi sensor.
I have been unable to duplicate the issue on demand. It can sit and idle for an hour and not have any problems. Driving it around the parking lot while it's hot still doesn't invoke failure. I did the 'wiggle' test on the harnesses and checked the connectors; wiring is fine. I doubt it's a fuel issue based on how on/off the stalling is. There is no sputtering, no shaking, nothing that would indicate fuel pressure has been lost or is dropping. It either runs 100% fine or it's 100% off (like ignition or signal problems). And its only 'off' for about one minute or so after it stalls, then it restarts with no issues (seems like an overheating electrical component to me). Having said that, I already planned on changing the fuel filter and pump on my next wave of replacement parts (the fuel filter does look much newer, so I believe it has been changed recently before I obtained car).
My current project is the Opti area, and I do not want to start this project, remove the opti, and go 'damn, look at all those leaking seals/crappy parts, wish I had replacements.' This is why I am looking for a recommended parts list from someone that's done this to have on hand before I start this. Anything else recommended while I'm in the area? Thanks again!

 

It’s definitely that after market opti......I’ve been there.

When they get hot they tend to do what you are describing.

Then one day they just stop working altogether and you are stuck somewhere when you least expect it.

Get an AC Delco rebuilt or the opti dr on a EBay reconditioned opti.

 

Theres a Reman GM unit in the parts section

 

When I had similar issues, it was a worn out connector. They would get hot and expand a little and wiggle a little and have intermittent connections. This was after listening to the (at the time) mob of parts throwers saying since it was an lt1 all problems are the opti.

Do yourself a favor and cut off all the old connectors and put new ones on, and THEN consider the opti.

 

I could be wrong but I thought I read somewhere that not all GM Reman opti's have the Mitsubishi reader. Dan

 

Do you know if the current AC delco remanufactured Optis have Mitsubishi sensors??

 

I do not believe the ac delco have new sensors! No one has them just send it to the opti doctorhe can tell if it the sensor or bearing.I had him rebuild mine and i also have a new MSD which has not the best write up. My replacement was a ac delco which seems to run okay. If you do replace it your self use clear marine or high end weather tite caulk on theout side of the unit to stop water from pump entering it. Also vent it for air movement.

 

If you suspect the opti, then there are tests to determine if it's failing. Doing it is a big job, If you spend an hour or two doing some testing, you might find something simple. If you decide to do the job, there are seal installation tools that orient the seal lips so they don't leak.

 

Saw you mention timing cover gasket...be advised that timing cover also seals against the oil pan gasket, may cause extra headaches if you tear the pan gasket which would be challenging to replace with the engine in car.

 

After replacing the OEM opti with two unsatisfactory units I am now on my fourth, my first from these guys:

https://petrisenterprises.com/

I like it. These guys do the internals as they should be. I talked with them before purchasing. They really know their stuff. With 140K miles on it my '96 now has its old pep back.

 

Pulling the timing cover also requires pulling the harmonic damper and its hub. The hub can be left in place if only the distributor, water pump, and their shaft seals are to be serviced.

Live well,

SJW

 

Really important: not all water pump gaskets are created equal. This one allows the bolt threads to hold the gasket in place while you wrestle the pump in place. Some don't and are a pain to get situated. Use this one, get two.

https://www.ecklerscorvette.com/corv...1992-1996.html

Also, if you get a seal that is teflon for the cover you don't lube it. Be sure to put good thread seal on all bolts. No need to apply anything to H2O pump gaskets. They go on dry.

In order to remove the inner hub of the harmonic balancer you can simply undo the motor mount bolts and then put the nuts back on just two revolutions. Then jack up the engine till it gets caught on the nuts. That should give you enough clearance. Only necessary when replacing cover. For only opti just remove outer ring. The 3 holes of it only align on inner hub one way IIRC. However, if you do remove the inner balancer make sure to mark it and don't let engine turn after that. It has to go on in same position. Also, when putting inner hub on make darn sure you have enough threads started before applying too much pressure to bolt to cinch it up. It is a very tight interference fit! This all relates to my '96 LT4. Whether or not this is the exact same as yours I do not know.

 

It’s typically the high voltage side of the opti system that fails. Get the LTCC Kit and LS2 coil packs. Your opti issues will be a distant memory.

 

Thanks for sharing that. With new oems disappearing,. How did you find them? There's a ton of garbage out there.

 

I just did a search of opti's since the MSD was so disappointing. I called and talked to the guy, or one of them, and he reiterated everything I had researched about the opti problems. He knows his stuff and does the internals the way they should be. Hopefully he will keep the service going and not sell out to another entity like OptiSpark did years ago. The company that took over really screwed the product for more profit margin, in my opinion. Petris appears to be the way to go nowadays. BTW, I have owned the '96 since '99. I like doing repairs only once when I start turning wrenches. I can't afford to have others do my work, too many vehicles and too much insurance. I am insurance poor!