1993 z28 bad opti?


93z28demon
09-12-2010, 10:54 PM
i have a 93 camaro z28 i have replaced the opti and the waterpump not even a year ago plugs and wires too it runs when it wont's to

93z28demon
09-12-2010, 11:03 PM
the camaro starts and the SES light is on and sometimes the camaro dies right after start up and some times just dies going down the road and has intemit rmp loss and when it looses rpm the SES light goes out and comes back on it has no opti related codes has some quad driver module codes related to emissions and some times the rpms come back and it keeps running i am a very frustrated

wrightz28
09-13-2010, 08:20 AM
You're 100% certain the water pump gasket is not leaking on the opti?

93z28demon
09-13-2010, 08:54 PM
yes the gasket is not leaking i am geting my uncle to go ahead and replace the opti it has a lifetime warranty any other ideas thanks

The_Bandit
10-24-2011, 04:52 PM
Hi there,

My 93 Z28 is doing the exact same thing...I've had the car a short time, but the previous owner says he changed the opti (distributor) just a few months ago...I don't know if he changed the water pump and/or gasket though.

Curious...did you find out what the problem was?? A chevy dealer thinks it's the opti...and they are about to change it...including the diagnostic, parts, labor and taxes it's going to be up over a $1000. So...I'd love any info you might have...

here is a vid of what mine is doing..
http://www.youtube.com/watch?v=lr07LyqzZPA

Tech II
10-24-2011, 07:20 PM
Optispark on the "F" cars and the Roadmaster, were a pain in the butt to diagnose....

One problem was the Water Pump....it was positioned above the distributor....so if it leaked, it would leak on the distributor, and the distributor would misfire....

Another problem was a fresh air line that would go from the snorkle to the distributor...if that became plugged, I guess the best way to describe it, the air in the distributor would become ionized, and cause problems...

Another problem in working on these, is knowing what was previously replaced....in some cases, it's just the cap and rotor....in some cases, it's the whole distributor.... some garages don't want to mess with a misdiagnosis, and replace the whole distributor, when it may just need a cap and rotor....

Have seen these distributors replaced, but the car had the same problem, and the real problem was either a bad coil, or ICM, or the high voltage wire between the coil and the distibutor, or the plug/wires.....

When these cars came in for their 100k tuneups, customers would pass out when you told them the cost....the plugs were hard to get to......the wires, more often than not had to be replaced because they could be damaged removing them from the plugs....in order to replace the cap and rotor, the waterpump had to be removed.....since it was already off, it was recommended that it be replaced at this time.....then the wires were a horror show(forgot how many hours book time was on these wires).....

To diagnose these systems, you needed the GM Tech II scan tool, and the trouble trees had to be followed to the letter.....

j cAT
10-25-2011, 07:36 AM
Hi there,

My 93 Z28 is doing the exact same thing...I've had the car a short time, but the previous owner says he changed the opti (distributor) just a few months ago...I don't know if he changed the water pump and/or gasket though.

Curious...did you find out what the problem was?? A chevy dealer thinks it's the opti...and they are about to change it...including the diagnostic, parts, labor and taxes it's going to be up over a $1000. So...I'd love any info you might have...

here is a vid of what mine is doing..
http://www.youtube.com/watch?v=lr07LyqzZPA

welcome to the forum.

when you post your issues give the dtc failure codes. also give what your issues are and any testing results/things found good or bad.

the opti distributor is a very expensive part. since I own one, it is best not to wash the engine. also the water pump on my vehicle has a hose connected to the water pump weep hole,which directs any weeping coolant to the lower area which will not blow on anything .. this weep hole leaks from time to time . not alot but any coolant getting into the opti will cause you to replace it .

as mentioned the coil has corrosion issues. any plug wire work will require removing the tires for correct removal/routing. using a tool to properly remove these wires is recommended. the plug wires require dielectric grease to be plced in the plug boots. the wires need be resistance tested for proper amount. the opti connection electrical connector also can get damaged by corrosion or wires get damaged.

some china opti are defective . when replacing the opti or getting to the opti for inspection the coolant must be drained out of the engine. this will require removal of the knock sensors. this will drain the engine completely. if not done the opti will get coolant on/in it.

1000.00 to replace this opti is a good price. the opti costs about 450.oo alone. labor if done correctly will add up to many hours.

replacing the water pump requires proper testing on install so that the coupler does not damage the ceramic water pump seal. the gaskets must be completely removed and new gaskets must be the correct thickness ..

I have found on the internet . many good pictures with proper proceedures on this work . it takes time and it the opti is damaged alot of part costs. the work is not that difficult with the wheels removed for plug wires/plugs.

from your video my guess is you are not doing this work. so this can be a big problem if the mechanic doing this is not properly trained/has the proper preceedure to test/replace these components.

make sure they have the proper proceedures/knowledge !

The_Bandit
10-25-2011, 05:21 PM
Optispark on the "F" cars and the Roadmaster, were a pain in the butt to diagnose....

One problem was the Water Pump....it was positioned above the distributor....so if it leaked, it would leak on the distributor, and the distributor would misfire....

Another problem was a fresh air line that would go from the snorkle to the distributor...if that became plugged, I guess the best way to describe it, the air in the distributor would become ionized, and cause problems...

Another problem in working on these, is knowing what was previously replaced....in some cases, it's just the cap and rotor....in some cases, it's the whole distributor.... some garages don't want to mess with a misdiagnosis, and replace the whole distributor, when it may just need a cap and rotor....

Have seen these distributors replaced, but the car had the same problem, and the real problem was either a bad coil, or ICM, or the high voltage wire between the coil and the distibutor, or the plug/wires.....

When these cars came in for their 100k tuneups, customers would pass out when you told them the cost....the plugs were hard to get to......the wires, more often than not had to be replaced because they could be damaged removing them from the plugs....in order to replace the cap and rotor, the waterpump had to be removed.....since it was already off, it was recommended that it be replaced at this time.....then the wires were a horror show(forgot how many hours book time was on these wires).....

To diagnose these systems, you needed the GM Tech II scan tool, and the trouble trees had to be followed to the letter.....


Thank you very very much. This is great information.

The_Bandit
10-25-2011, 05:23 PM
welcome to the forum.

when you post your issues give the dtc failure codes. also give what your issues are and any testing results/things found good or bad.

the opti distributor is a very expensive part. since I own one, it is best not to wash the engine. also the water pump on my vehicle has a hose connected to the water pump weep hole,which directs any weeping coolant to the lower area which will not blow on anything .. this weep hole leaks from time to time . not alot but any coolant getting into the opti will cause you to replace it .

as mentioned the coil has corrosion issues. any plug wire work will require removing the tires for correct removal/routing. using a tool to properly remove these wires is recommended. the plug wires require dielectric grease to be plced in the plug boots. the wires need be resistance tested for proper amount. the opti connection electrical connector also can get damaged by corrosion or wires get damaged.

some china opti are defective . when replacing the opti or getting to the opti for inspection the coolant must be drained out of the engine. this will require removal of the knock sensors. this will drain the engine completely. if not done the opti will get coolant on/in it.

1000.00 to replace this opti is a good price. the opti costs about 450.oo alone. labor if done correctly will add up to many hours.

replacing the water pump requires proper testing on install so that the coupler does not damage the ceramic water pump seal. the gaskets must be completely removed and new gaskets must be the correct thickness ..

I have found on the internet . many good pictures with proper proceedures on this work . it takes time and it the opti is damaged alot of part costs. the work is not that difficult with the wheels removed for plug wires/plugs.

from your video my guess is you are not doing this work. so this can be a big problem if the mechanic doing this is not properly trained/has the proper preceedure to test/replace these components.

make sure they have the proper proceedures/knowledge !

Thank you very very much. This is great information. The car is at the largest chevy dealer in the city, I hope the person working on it loves these cars as much as I do! (maybe I'll have to learn how to do this stuff on my own). Thanks again.

j cAT
10-25-2011, 05:56 PM
Thank you very very much. This is great information. The car is at the largest chevy dealer in the city, I hope the person working on it loves these cars as much as I do! (maybe I'll have to learn how to do this stuff on my own). Thanks again.

this will give you an idea of whats with this job.


Complete vented Optispark replacement guide

Way back in early '94 when I first picked up my Impala SS I was fairly disappointed when I opened the hood. You see I had read that the Impala engine compartment was supposed to contain one of the most powerful small block Chevy engines ever, the LT1. Unfortunately it did not look like an LT1, at least not like the one in the Corvette.
1992 - 1996 LT1/LT4 Corvettes (Y-Body)
1993 - 1997 LT1/LT4 Camaro's, Trans Ams (F-Body)
1994 - 1996 Fleetwood (D-Body)
1994 - 1996 Impala, Caprice, Roadmaster (B-Body)
After studying both the Corvette and the Impala engine bays, I determined that the dramatically different appearance between these two nearly identical engines was limited mainly to the dress items attached to the top of the respective engines. After studying both the 'vette and Impala parts catalogs I determined that it would be very easy to duplicate the look of the Corvette LT1 in the Impala by first removing the "home plate" induction resonator and it's bracketry, and then installing the fuel injector rail covers and valve covers from the Corvette. This was surprisingly easy, and so dramatically changed the look of the engine, other Impala owners thought I had changed the engine itself!
Although these items can very easily be installed, there are a few modifications and adjustments that must be made, and several different parts are necessary to complete the job. The major appearance change comes from adding the Corvette fuel injector rail covers, and you can optionally also install the plastic Corvette valve covers as well. Since the valve covers are a direct bolt-on, there are no instructions necessary for them, other than what is already contained in the service manual. This text will focus on installing the fuel injector rail covers, which are a little more complicated.
Finally, from 1992 - 1994 the Optispark was what is known in the gearhead world as "unvented". The reason it is called this is because it does not have the vacuum hoses connected like the newer 1995+ LT1/LT4 engines have. What the vacuum hoses do, is they pull the moisture out of the Optispark.
What a lot of people don't realize is the unvented Optisparks are actually vented!! Yes, they have 3 weep holes at the base of the Optispark to allow moisture to escape. Well, all this does is pull moisture back in. Put cold water on a hot Optispark, it's going to suck the water in! This is the BIGGEST problem with the design.
Before you go out and buy a brand new 1995+ Optispark, be forewarned. You CANNOT bolt a 1995+ Optispark up to a 1992-1994 LT1. The CAM is different. You could change the CAM, timing cover, CAM gear, etc but this gets expensive, and is very labor intensive.
So, what is the solution?
You can do 1 of 2 things :
1. Change the Optispark out and be up and running again. However you risk damaging it again. There have been people who have had to replace a brand new Optispark because they got them wet.
2. Change the Optispark out with a modified unit.
The conversion process is simple!
Buy a older style Optispark (the one you're supposed to buy), and simply change the cap! Of course you will need to do a few additional things.

First let's start with the parts list:
GM Parts needed:

Optispark for 1992-1994 LT1's PN - 10457702
Cap and Rotor kit PN - 10457735 or
1995+ Distr. rebuild kit (Pep Boys or NAPA)
1996 Vacuum Hose Kit PN - 12556174 or
1995 Vacuum Hose Kit PN - 12555323
Order GM parts from http://www.gmpartsdirect.com/ or from your local GM dealer (yuk!).
Other Parts:

Inverse Torx Bit - E4, deep well!! SnapOn part number STLE40 - I stopped a truck, or you can order online at http://www.snapon.com/
2-claw puller - Autozone
2 water pump gaskets
Gasket Sealant
Vacuum T or a brass T that will screw into the manifold
Long Breaker bar, or torque wrench
Brass fitting for the base of the Optispark. I got mine from the local parts house that carries various hose/pipe fittings.
3/16" Drill Bit (slightly bigger than the hole your drilling out)
Bandages
Recommended :

Plugs and Plugwires
Converting the new Optispark
Remove your cap from your new Optispark. Nothing like taking apart something brand new eh?
Remove the rotor from the Optispark. This is a torx T15 I believe. Carefully remove the rotor, and the metal disc. Do NOT remove the slotted one! It's spot welded on for a reason. Only the disc directly behind the rotor should be removed.
Remove the middle spacer. This is the center portion of the Optispark body. Set aside everything, but the back plate. BE careful when handling this. Try not to get any grease, dirt or anything on the disc.
You will notice 3 holes on the base. Fill the center one, and the one closest to the long pointed portion of the base in with JB Weld or something similar. I drilled out the remaining hole. Try not to get the metal shavings in or on the Optispark. Next I tapped in a brass fitting. Do not use the center hole for this, as it won't clear the balancer hub. IF you can find a brass L fitting, this would be your best bet. I wasn't able to find one small enough, so I used a straight brass fitting from a local parts house.
Vacuum the metal shavings from the previous step. MAKE sure it's clean before you put it back together.
Reassembly is the same. MAKE SURE you don't forget to put the metal disc back in place. If you leave it out, the gap for the rotor and cap will be WAY off. The rotor and disc are keyed, but still make sure you put them in correctly.
Remove the old RTV Sealant, and put some new RTV on the cap at the electrical connection. Put it back together with the newer style cap. Lightly blow into one of the hose connections while closing off the other. You should hear no hissing.
You aren't supposed to turn the shaft on the Optispark (why I don't know), but I would still recommend slightly turning it (1/4 turn is enough) to make sure everything spins smoothly.
this is another guide ......
The Nitty Gritty
First disconnect your battery.
Drain your coolant. Be sure to open the bleed screws. This will help it drain much quicker. Remove the rubber intake bellow.
Remove the upper radiator hoses.
Disconnect the bottom radiator hose from the water pump.
Remove the coil wire, and the electrical connections from the Optispark and water pump.
Pull the belt tensioner out of the way, and loosen the accessory belt.
Remove the water pump. There are 6 bolts holding it in place. Additional coolant will dump out when you remove the drivers side lower bolt. Clean the old gasket material and set the water pump aside for now. You MIGHT need to remove the coil, but I didn't need to. Check the weep hole on the water pump to make sure it's not damp.
This is the fun part (for me at least). Remove the 3 bolts from the balancer. The Haynes manual says you can simply pull it off without a puller. I was not able to. I had to use a 2-clawed puller. I got mine at Autozone. I believe the one I got was the 6". Somebody is borrowing it as we speak for this repair! MAKE SURE you make a note of the position of the balancer in relation to the hub. Both the hub and balancer should be marked, but not keyed.
Remove the remaining plug wires. If they are old, you may want to replace them. Now is the time to do it!
Remove the 3 bolts that hold the Optispark in place. Pull it straight out. There is a shaft that connects the Optispark to the Cam gear. This may or may not come out with the Optispark.
At this point, you should look at the old Optispark and make a mark of where the notch (spline) is. This will assist you later.
This would be a good time to put some gasket sealant on one side of the gaskets, and place them on the water pump so they can dry. This will make reinstalling the water pump much easier.
With the old Optispark to compare, rotate the shaft on the new one until they match up.
I found it easier to insert the shaft on the cam shaft, and then sliding the Optispark on top of it.
IF there is any gap on any of the 3 mounting screws, you probably haven't lined the Optispark up correctly with the spline on the shaft. It should slide all the way on with no gaps on any of the mounting areas. Tighten the bolts, but do not over tighten.
Run your vacuum lines. The clip goes on the alternator bracket. MAKE SURE the hoses are going to clear the belt.
The hose that has the filter and regulator is the vacuum supply.
Poke a hole in the rubber bellow (on the top) and push the L into it.
Put a T or something similar on the drivers side intake manifold, and hook the vacuum hose up.
Reconnect the plug wires.
Reinstall the 3 bolts on the balancer. Tighten the bolts to 60 Ft-lbs. Make sure you line it up properly (see step above where you removed it)
Put gasket sealant on the remaining gasket material, and reinstall the water pump. Tighten to 30 Ft-lbs.
Reinstall the belt. It is much easier to do it now before you do the next step!
Reconnect all the hoses, the coil wire and the other misc electrical connections (temp sensor, Optispark connector, etc).
Lightly tighten the bleed screws.
Refill the cooling system until it is full. Place a rag around the bleed screws, and bleed off the excess air. Don't let any coolant get on your new Optispark!
Check and recheck everything.
Fire it up.
If everything looks good, your done!
You should also pull the hose out of the bellow, and check for vacuum. If it gets clogged, or a hose gets pinched, it will cause the cap to cave in, and burn up the rotor.

The_Bandit
10-25-2011, 06:07 PM
this will give you an idea of whats with this job.

Complete vented Optispark replacement guide

...


I just read all that...and can't believe the level of detail you have accomplished here. I think (next spring or maybe over the winter) I'll do this task...or I might wait until the "new" one fails...it sounds like it will. Regarding this opti-spark issue... I guess this explains why I can wait a little while and start the car again and drive a bit more...the strange thing is though...that if the issue occurs, it does so at around 3200 rpm like in the vid, and then I can "sometimes" start it up right away, or worse case scenario I need to wait 5 or 10 mins...but then once it starts, I can drive it all around everywhere as long as I keep the RPM's under 3 grand or so. So...I don't know how these opti-sparks work, or why 3200rpm is a magic number, but that is how it goes. The mechanics had a heck of a time making the issue happen again, it's so dang intermittent.

Anyways, I am going to copy and save what you all have posted in a safe place, because I feel that myself (and perhaps the proper mechanic) will benefit from it. I'm very impressed with this forum, because of these great suggestions/possible answers.

Kindly,

rich

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