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Optical-Spark; Optimum Problem!

compyelc4

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Joined
May 1, 2002
Messages
608
Location
Dayton, Ohio
Corvette
'95 LT1 Coupe, Comp Yell; C6 Roadster, Vel Yell
Folks-

I am almost at the end of my wits and automotive expertise with my '95. 17k miles. Can anyone help before I have her hauled out of the driveway and up to the Chevy service tech! Right now, my pride is hurting real bad and a trip to the dealership will just kill me. Whoever can help me put this puzzle together will, forever, be in my heart! I WANT MY VETTE BACK!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! You may have read an earlier post about this before all heck broke loose.

Symptom History:
1. Has always start and run extremely well.
2. A week ago I tried to fire her 3 times before she would stay idling, then ran well for 1 day.
3. Next start incident, she coughed, backfired (sounded like one, anyway). Set code and displayed Check Engine Light all the way home. Shut her down, restarted immediately.............no code. Ran and started great for the balance of weekend.
4. Next start incident............ errrr, errrr, errrr, errrr....no start. Turned key off....hooked up timing light....asked better half to give the key a go and..........immediate start and ran fine balance of day. THIS IS GETTING WEIRD!!! No Check Engine light.
5. Next start incident............same thing only this time she started and farted like she did in #2, above but never did recover. No Check Engine light.
6. Time for mister TECH II. Ran codes and found 042-Ignition Control Circuit Grounded and 036-Hi-Resolution Pulse Circuit.
7. Ran ignition tests by the book and everything pointed to either a bad spark module or bad coil. Replaced both..............NO CHANGE. Crap, THIS IS GETTING REAL UGLY.
8. Checked all tests and fussed and fumed with her all day. She would not start once. I must have tried 50 times! No spark.
9. The next day I gave her ONE MORE START and she started and ran real smooth for about 5 seconds. Then she just shut down. This happened about 15 times in a row.
10. I gave up for the day.
11. Sunday morning I thought, "What the heck!". I turned the key and she fired right up and ran very smoothly for about 10 minutes, then she started sputtering and died.
12. During this moment of nirvana I had the Tech II attached and monitored all the systems. All were right on the money. Oops, when she died she set those 2 codes again.
13. I'm going after the Opti-Spark, but only 17,000 miles....COME ON! The front end is as dry as a bone. Could it be the opti????
14. The code 42 has me worried. Some books say it could be a bad ECM. The Ignition Control circuit is the only OUTPUT circuit in the ECM ignition circuit that produces that control signal. This pulsing (12v I think) feeds the optical ("eye") emitter, kind of like the "base" on a transistor . The High-Resolution Pulse Circuit (and a Low-Resolution Pulse Circuit) are produced directly by the Optispark and feed the ECM so it knows the location and rpm of the cam. See what I mean? This thing has too many interrelated variables for me?
15. BIG QUESTIONS: IF THE OPTI-SPARK IS HOSED WHY DID THE ENGINE RUN SO GREAT FOR THAT 10 MINUTE PERIOD. SAME QUESTION ABOUT THE ECM? Also, why does it sometimes fire right up every time (only to die quickly) and sometimes no spark at all.
16. Am I thinking too hard, or not hard enough?
 

compyelc4

Well-known member
Joined
May 1, 2002
Messages
608
Location
Dayton, Ohio
Corvette
'95 LT1 Coupe, Comp Yell; C6 Roadster, Vel Yell
Forgot something! A couple of internet posts show code 036 to be MAF circuit, or something like that. I had the TECH II (you know, that $2500 GM thingy) set up for '95 LT1 AUTOMATIC. The scope indicated she was reading OBDI codes. It did show 036 to be the Hi-Res Pulse Circuit!
 

supernatural400

Well-known member
Joined
Feb 25, 2001
Messages
410
Location
massachusetts
Corvette
1993 SuperNatural 400 #5 /99 LS1 Z28 N2O equipped
did you at any point get the opti wet ?
 

compyelc4

Well-known member
Joined
May 1, 2002
Messages
608
Location
Dayton, Ohio
Corvette
'95 LT1 Coupe, Comp Yell; C6 Roadster, Vel Yell
Not recently. I think a sprayed her off last August and again this April. I do not remember soaking the front end however. Never had a miss though! You can bet I know better now. I believe the '95 has the "new" forced ventilation system to keep her dry.
 

supernatural400

Well-known member
Joined
Feb 25, 2001
Messages
410
Location
massachusetts
Corvette
1993 SuperNatural 400 #5 /99 LS1 Z28 N2O equipped
They redesigned the 95 and 96 with a seal around the housing , but I still think you can get it wet. For what it's worth, you might want to bite the bullet on this one and go to the dealer. I know it hurts to do that, but the time and aggrevation you seem to be going through with this problem might be worth the trip. To soften the blow just take it there to find out whats wrong , then take it home and do the work yourself
 

compyelc4

Well-known member
Joined
May 1, 2002
Messages
608
Location
Dayton, Ohio
Corvette
'95 LT1 Coupe, Comp Yell; C6 Roadster, Vel Yell
I have an appt bright and early Monday morning. I'm betting on Opti-crap or Computer (ECM) failure. I noticed the funniest thing yesterday before I shut the hood for the last time til fixed. You may have caught my previous post concerning trouble with no courtesy lights. On the sixth start-up attempt yesterday, I had the driver door open. Of course, no courtesy lights on. The engine started, immediately set Check Engine Light, proceeded into Open Loop mode. Actually ran pretty well for "no computer control". The dardest thing... at the moment she went to open loop, the courtesy lights came on! I could not believe it. I duplicated that 3 times in a row!!! Computer bypassed = courtesy lights. Computer in closed loop (although only for 30 sec. or so) = no courtesy lights. Obviously, the lights now are the least of my problems, but I have NEVER run into gremlins like this before.
 

BigRed

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Joined
May 23, 2001
Messages
948
Location
Edmonton
Corvette
1985 Bright Red Rocket
Hmmmm could this be a Alarm problem?! Seriously! My 93 G/Cherokee did this to me last year.

I unlocked it tryed to start it NOTHING waited like an hour NOTHING I went under the hood pulled and checked everything NOTHING (Didnt have the benefit of a code reader)

So as I was going bald from pulling my hair out (And missing my appointments) I called my good buddy Dale (He the head mechanic at Southtown Chrysler Jeep) He listened in detail to my problem then outta no where he started LAUGHING HIS ARS OFF.

Obviously this peeved me off, he said relax! go back to my Jeep put the key in the door turn it Left then right..Turns out the alarm was in silent mode and killed my ignition! As soon as I did what he said VROOM No prblms

He also said (On the Jeep) to keep the drivers door open and push the two buttons on my onboard computer and hold them to reset it...Never had a problem since

Anyway back to yours you may have a silent alarm being activated somehow and its killing your ignition. Someone here with more knowledge on the VATS or whatever it is you have may be able to help you more!

But just for giggles try the key lock thing and/or/both use your keyless entry mabe you'll be surprized!
 
R

RubyDropTop

Guest
I'm not a betting person, but my money is on the Opti-Crap...it's crapped out on you. Sadly, 17k miles is not unheard of for an Opti to kick the bucket. I have read stories of the Optis going out at 10k miles and LESS! They are GM engineering at it's best.

You may also want to have the water pump replaced at the same time. It sits above the Opti and will eventually leak right onto it. Yeah.

Let us know how you make out. I bet it's the Opti....symtoms sound too much like a bad Opti.
 

69MyWay

Well-known member
Joined
Jul 3, 2001
Messages
4,364
Location
Auburndale, Florida
Corvette
1969 Killer Shark
So, if my guess is right, you will be my friend forever?????

Hmmmmmm, anyway.

Fuel Pump/fuel pump circuit


Sounds to me that you have a fuel pump that is on the fritz a good part of the time now. You can easily check with a good quality gauge. Just because you hear it whinning when you turn the car on does not mean it is putting enough pressure to the rail to start, or even keep the car running.

If it is not running at all at times, I would first check the relay, the power source to the relay, then back to the pump. At least the pump is fairly easy to replace. At 17K you should not need to replace, but when they sit up often, the fuel tends to gum things up.
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Hmmmmmmm!

Well... without the car in front of me...it's a tough one to fix VIA the Oujai board of online stuff.

1) If the VATS was intermittant the car would not CRANK...VATS interuppts the STARTER circut.

2) I agree with Chris... check the fuel rail... break down & purchase a fuel pressure gauge. The fuel rail has a schrader valve on it you need 36 ( ish ) lbs of pressure to run. The fuel pump is an area of concern... DO NOT ASSUME ANYTHING!

3) IF the opti -CR@P is at fault you will not get spark... even in LOW REZ mode the car sould run... Jerry rig a plug off 1 cylinder and ground it to the rocker covers... that will be the spark tester.... MAKE SURE THERE IS NO FUEL SMELL otherwise BOOM! and do not run the engine to long with 1 hole not firing.

4) If you are in a NO START condition.. have you tried sparying Quick start down the Snorkle? Does it light then?

5) Do the horns work?.. If you trip the alarm I do not believe there is a "silent mode" available in your year.

Do these tests.. and get back to us..... help is on the way.

( The door thing is weird.. have to chew on that)
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
AND

How is the condition of the connectors for the coil etc.... clean or scummy?

How are the wires?

CHECK FOR PROPER SEATING OF THE COIL WIRES @ the opticr@p.


Run thr car @ night to check for Corona of the coil wires & plug lines.

If you want to force the car into OPEN LOOP

Pull the TPS sensor... that will freak it out.


Mike
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Correction

The vats also enables the fuel line ( pump power).. once the car is running the 2nd oil pressure switch keeps the pump circut closed as long as there is good oil pressure ( over 10psi I believe )


Could be the fuel pump relay opening up...

But you need the fuel pressure gauge to confirm this.



Vig!
 

compyelc4

Well-known member
Joined
May 1, 2002
Messages
608
Location
Dayton, Ohio
Corvette
'95 LT1 Coupe, Comp Yell; C6 Roadster, Vel Yell
Thanks and Comments Not Getting Through to You Guys

I've responded to your questions and posted updates twice in 2 days. The system keeps telling me I am not signed on and I lose my replies to you.

Don't know what is happening. If I had no hard luck, I'd have no luck at all this week.
 

Rob

Site Administrator
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Messages
13,780
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1990 Corvette ZR-1
Re: Thanks and Comments Not Getting Through to You Guys

compyelc4 said:
I've responded to your questions and posted updates twice in 2 days. The system keeps telling me I am not signed on and I lose my replies to you.

Don't know what is happening. If I had no hard luck, I'd have no luck at all this week.

I just got your email. You had "Browse Boards With Cookies" turned off. If you turn this setting off, the system won't keep you logged in. I have changed it from my end so you should be all set. If you continue to have problems, please let me know.
 

compyelc4

Well-known member
Joined
May 1, 2002
Messages
608
Location
Dayton, Ohio
Corvette
'95 LT1 Coupe, Comp Yell; C6 Roadster, Vel Yell
Guys. Thanks for your concern and great suggestions. I considered and checked into every one of them.

Here is the final chapter of this problem start and run condition. I'll reveal the ending now................ OPTI-CRAP crapped out. GM replace that and the connector harness. I'm not sure what the internals of the Opti look like (that's this weekend), but the external Opti connector pins and the female harness connector pins were all corroded with a blue, powdery crap. It looked just like copper sulfate (corroded copper!). I discovered that just prior to taking it to (or shall I say having it hauled off to) the dealership. I cleaned the connections as best I could (kind of like performing vascular surgery on an ant), hooked her all back up. She started like crap, but ran terrific for about 10 min. During this time she missed a few times, then crashed, never to gain her spark back. That's when my wife said, "Give it up. You've done the best you can. I want our Vette fixed............Now go call a tow truck, and then mow the grass, and don't forget to eat tonight, in that order!" Yes m'am. I complied. I was beat. I knew it was the Opti, but I was just tired of reading and getting run-around electrical test results with nothing FINAL pointing directly to the Opti. You know what I mean?

Got her back (the Vette, that is) a few hours ago. Runs just as good as ever. I've never been so happy to fork over $840 in my life. I felt like I was purchasing a brand new Vette for that $840. Matter of fact the gal that took my cash gave me a piece of candy for having the highest repair cost of the day. Ahhhh..... peace of mind back. Heck, I even bested my best time on my nightly jog tonight. Attitude is everything, isn't it?!
 

69MyWay

Well-known member
Joined
Jul 3, 2001
Messages
4,364
Location
Auburndale, Florida
Corvette
1969 Killer Shark
I hate it when I am wrong, and the right answer was the more expensive alternative. At least you got her back and just in time for a fresh coat of wax and some summer time cruising this weekend.

I am working on a 1936 Ford that I put a 1995/6 LT1 from a F body in last year. It has started to run poor while cruising down the highway. I hope it is not the opti unit as it is difficult to access in this car, AND we put a new one on it when we installed the motor.

Hope you have plenty of fun cruise time on that baby.
 
R

RubyDropTop

Guest
Darn, I KNEW I should have put money on this one! :) Your symptoms just sounded too much like a bad Opti to me. That's how they act when they are on their way out.

Glad that you had it replaced. Did they do the water pump too? Hopefully you will get more than 17k miles out of this one. Crazy, isn't it?
 

compyelc4

Well-known member
Joined
May 1, 2002
Messages
608
Location
Dayton, Ohio
Corvette
'95 LT1 Coupe, Comp Yell; C6 Roadster, Vel Yell
To "Ruby", "69" and others:

Thank you so much for your advice and warm wishes!

Ruby - They looked at the pump. I'm sure they would have loved to replace that too, but amazingly they advised to keep the one I have. They said it was tight as a drum and should go the typical GM distance. You can bet I'm going to keep a daily eye on the pump and..................no more engine washes!

69 - I feel like an Opti-crap electronics expert now. Let me know what your codes are. At least I diagnosed the Opti correctly via electronic diagnosis. Was just sick and tired of reading, testing, and wondering what I would have felt like if I had installed the new Opti and the thing still would not run worth a poop! The very first thing I would check if you get spark-related codes is the terminal attachment at the input to the Opti.
 

96Holly

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Joined
Apr 30, 2002
Messages
117
Location
Livonia, Mi, USA
Corvette
96 LT4 Polo Green Coupe
Great idea...

Thanks for the idea for looking at the conections. I am STILL (long story) in the process of changing out my opti-------

Im going have to watch the conectors to the opti...

Great site isn't it?
 

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