Let me start at the beginning .
I was cruising along on I-10 when my Vette started missing and backfiring.

I was able to get off at an exit close by.
I called a tow truck and by the time it arrived the car was running fine.

I took it to a shop the local corvette club
Recommended.
They couldn't find any thing wrong.

It left me stranded again a few days later.
Since I have a Delteq ignition I suspected that's what it was but it checked out fine according to the trouble shooting guide.

It got to where it would turn over but would not start.

After playing around and not getting anywhere I called a shop familiar with the ignition about 70 mi away.

I called a tow truck and the driver asked if it would start.

I told him it hadn't started in a month.

I tried it and the damn thing started!!

The shop had it a week and it kept running.
Finally, it started acting up.

They told me they believed it was a security issue.
I told them I never thought of that.

After waiting a couple of weeks for their
Friend at the local Chevy dealer to confirm their suspicion with some electronic devise, he confirmed that suspicion.

They said I needed to get the security deleted from the chip in the ECU.

I informed them that it was an aftermarket chip from Ed Wright.

I had the shop overnight the chip to Ed because he was getting ready to go racing for a week or so.

The shop called and told me the chip was back in the car and they started it many times and drove it around.

They said it was ready and I went to get the Vette. I was happy!

20 mi later I stopped to wash the car. It started and I let It idle when I saw the tach needle jump and then it quit.

It would start, miss & spit, and quit.

I had just spent over $400.00 and I was furious!

I tried calling the shop and could not get anyone.

I ran the battery down trying to get it to stay running. Hello tow truck.

After waiting over an hour for the tow I tried a jump. The car started and ran fine??

I made it to Cruising the Coast, about 80 mi. away. I drove it around that night and parked it.

The next night when I went to leave the Vette started right up.
I made it about a mile down the road and it started doing the same thing as before. Missing,backfiring etc.

I didn't want to leave it so I kept trying to get it going and it finally did and off we went. This happened about 5 or 6 times. Each time I was about to give up when it would run good and off we would go. It always would turn over.
I'm lucky I didn't blow the heads off it was backfiring so bad! I did blow the insides of my CAT’s.
The pieces were hitting my cousins car behind me.

After I finally got it home I then thought maybe it’s my fuel pump and that’s why it backfired because it was running lean.
I changed the pump and the car started and ran fine.
I thought it was “MAYBE” the answer. It wasn’t!

It quit on the way to fill the tank. I had 5 gallons on board.
After checking everything including my injectors I went again to a different president of a Corvette Club.
He told me about a place which was close by where the guy has been working on Vettes for over 40 years.
I didn’t even know about the place!

Oh by the way. I called Ed Wright and asked him what he thought.
When I told him the problems I was still having he told me in his gruff voice “You didn’t tell me it happens while you were driving. The security issue is only when your car will turn over but won’t start!” That’s more money I threw out the window. Who knew?

Anyway, back to the shop that’s been working on Vettes for 40 years.
I had the car towed (again) to his shop.
In a few hours he said it was my Opti Spark.

At this point I had my suspicions that the Opti was a problem.

In about four hours he called and said the rotor was in pieces. I informed him the DelTeq ignition doesn’t need the rotor. He said I know but these pieces would fly around in there and block the light sensor at times. It sounded logical to me.
He called me and said it’s running fine, he drove it around.
I said great!
When I picked the car up I told him if it runs good for more than two days he’s the Man.
He laughed and said that’s a GM Opti, you won’t have anymore problems.
One mile down the road the car quit!! I could not believe it!! Another $400.00 down the tubes.

When I called him he thought I was kidding him. I told him I wish I was.

While waiting for the “tow truck” I tried numerous times to get it started but it would not even try.
As usual it always turned over.

A few days later he called and said it now appears it’s the ECU.
I say ok,do it!
He sent the ECU off to be checked. The company tells him they found some problems and some corrosion and will repair it.

A couple weeks goes by and I call to find out what’s going on. He tells me he just put the ECU on the car and it would not start and the digital dash was jumping all over the place. NO!!
He said he called the place back and they said to send the ECU back.

He calls me back a couple of weeks later and says well, we got the ECU back. The dash isn’t jumping around. The car starts right up but only stays running for about 10 min. then quits. When will this end?
He says he called the company and they are sending him a brand new ECU.

A few weeks later he calls and said the Vette is running great. Eureka! It’s about time.

Another $500.00 bucks and the car is running great!
I drive it for about 6 miles, got on it about 3 or 4 times through the gears, no problems.
I park it in the garage and didn’t get back to it for over a week.

Just before Christmas I tell the wife let’s go for a ride in the Vette. She says you want me to follow you?
I say Nah it’s fine now.
I should have listened to her as usual. The car started acting up just like it did when it all started and then it quit. It will start missing badly. The tach needle will jump and it will spit and back fire if you try to keep it running by playing with the gas pedal.

When it quit, I just pulled over and called the shop.
I could tell by his voice that he didn’t want to see my car again. He said before he called me to tell me the car was ready he drove it for about 50 miles. I told him that doesn’t mean anything. Everytime I think we’ve found the problem it happens all over again.

While waiting for the “tow truck” my wife says try it again, you know how it acts sometimes.
The car started up, acted fine, and I drove it about 2 miles to his shop and he gave me and my wife a ride home.

I am at a total loss as to what’s going on with this car.
By the way, the digital dash started jumping around but went back to normal before the car started missing and then quit.

Anybody out there have any ideas?
I was told an Andy Bogus had a similar problem and he's on the forum.
Thanks
Herb

Welcome to the forum Herb.
Andy is the forum - owner that is.

His problem isn't over either.
http://www.corvetteguruforum.com/modu ... hp?topic_id=16101&forum=1

What year?

In all this, did anybody check the codes?

Welcome, Herb! There's some smart folks here, hopefully they will be able to help you solve your problem once and for all.

Your symptoms sound identical to mine.

I have sent my Dynaspark opti and the LTCC brain out for testing.

Personally, I suspect the dynaspark, because he had a run on bad sensors about the time mine was being serviced for another assembly related issue.

There is a chance that the DelTeq is causing it, but at this time, I don't know how available they are for diags.

Can you revert back to a pure optispark?

Considering the nature of the problem, and what I have learned about the opti, I would blame the opti... here's my logic... and I haven't found where my assessment is wrong; but please, if someone thinks I am smoking crack, let me know.

From what I can tell, the ECM does not care if TOO much info is sent - it gets cranky when not enough is sent. And I think that is what the sensor in my dynaspark is doing.

You mention EGR delete... I replaced my valve because that was causing a much of the problem as anything! It was shot and was causing a combo vacuum leak and exhaust leak, causing the computer to go nuts.

Has anyone run a data log?

Any codes?

Welcome aboard Herb. Yes, I am the one from CF that suggested you ask around here. Tell us more about the dash acting up --- "I am at a total loss as to what’s going on with this car. By the way, the digital dash started jumping around but went back to normal before the car started missing and then quit."

I am really wondering about a screwed up ground.

All the engine controls are grounded to the transmission/bell housing. If those are compromised, then things can get stupid.

I have had no other symptoms - ie, dash flashing about. Just the poor operation.

It will start, but the idle sucks. Or, it runs great and then falls apart. Very unpredictable.

I recommend getting an Delteq OPTI box and swapping it for testing purposes. Maybe, just maybe, someone near you has one. If not, let me know. I may be able to help. I have a couple, but I am in Hawaii. So, its time consuming. The boxes are usually mounted right on the cylinder head, and can potentially be ruined/deteriorate due to the heads heat.

Welcome to the site!

A couple things...check the grounds as indicated. This is related to you saying the dash was jumping around.

The wiring on these cars is older and can sometimes shrink or chafe, etc. Not as bad on the newer model LT1s vs L98s, but still something to consider. That being said, when you have it running at idle, go under the hood and start wiggling wiring and harnesses around and see if that affects anything.

Matthew

Another thought - since you now have a new opti, is it possible to bypass the delteq system to rule that out? I know very little about the delteq system and how it runs.

Matthew

For anyone else interested:

http://www.delteq.com/

Quote:

I am not sure the availability of the DelTeq folks... You can try...

Quote:
Someone on another forum stated he spoke to one of the two that made the company. He is working on the MoBoard and will have it back on line soon. That was last year...
Anyways, you need to find people that have spare parts or used ones. I have spares, just in case. I can always revert back to Opti, as I have 3 or 4 of those with genuine Mitsubishi Optical sensors. Cap and rotor is easy to change.

As far as C4s go, I'm no expert, but I have been working on cars for a long time now and I have learned some general information that spans many makes and models and it's always worth checking into.

Voltage & Ground

I would have the battery load tested. Sure, it may hold a 12V charge when off, a 14V when running, and fire the engine ever time...but if a cell is bad it can cause 'phantom' issues.

I would also take the alternator to a shop that specializes in starters and alternators. Have it tested. If the diode trio is failing...even intermittently, you're voltage will be jumping all over the place.

Computers are VERY picky when it comes to voltage. They typically have a very small range where they are happy. Fall below or above those marks and the systems shut down and start back up very randomly.

Aside from battery and alternator testing...remove, inspect, and clean all main system grounds. Battery to chassis, engine, computer...both POS and NEG.

I have trouble shot a few nightmare situations like this and it ended up being a bad battery / connection.

I have a newer Optima, and to be honest, I don't remember seeing my voltage scatter during a poor run time.

The alternator is from a 96, and its 144 amp, hotter than the 124 I used to have. I know the 124 is dead. Also, the power and ground wires off the battery are new; as in 2.5 years old, fresh from OEM GM. They are the updated units with better sealing and such.

I am going to check grounds and valve train.

With Herb's wacky IP display, that's why I suggested electrical.

Wow! This forum is really active!

The Vette is a 93 LT1.
The opti has just been changed a month ago.

The car is back in the shop at this time.

I guess going back to just the Opti ignition will be the next step after checking the grounds again.

I'll commit hairy Kairy if that's what it is after all this money I've thrown at it.

The codes have been checked and the one before the Opti change
said something about computers not communicating with one another? That's what the Chevy tech told me and suggested the security deletion.

I met a guy on the other forum that has a data logger and if the shop that has it now can't figure it out he said he would hook up his data logger. He told me he's a low voltage engineer so maybe he can figure it out.

I talked to the shop yesterday and was told the car acted up but didn't quit while he was driving it but nothing showed up on his diagnostic devise he had hooked up when it happened.

The person from Hawaii that said they had a board for the DelTeq I just might take you up on it.

I'll keep everyone informed and thanks so much for your input.

Oh my... you have a problem with the CCM communicating with the ECM... God Bless you my friend.

At this point, all bets are off... If you have a new opti, where did it come from? Was a Cardone reman? Or a GM new? If it was a junk ass reman, there is your problem. They do suck, dude... they really do.

You have to realize that the DelTeq system is based off the Caddy Northstar ignition. There is a lot of GM in there. I would blame a replacement Opti first.

If you don't have CCM comm, you won't get an easy data log.

You see, the ECM has 2 (as does the CCM) of these chips called UARTs - Universal Asynchronous Receive/Transmit. There are two of them, coming off of a unique port to a common wire and then split again to 2 more unique ports on the CCM. The idea? IF one fails, the other picks up.

If both fail, the VATs won't send the appropriate handshake to the ECM to allow the car to start. It will crank, but it won't start.

Forum sponsor K&B Products fixes the ECMs, they are one of the only such shops who can fix a blown UART. They have the diags and the hardware and the parts.

My 92 has the same ECM... and you can find them on eBay from time to time. 1992 and 93 Corvette, and 1993 Camaro/Firebird, with LT1 use the same ECM. Just swap chips.

Check for Scoob The Core Man on ebay, I Don't know his handle... I got one from him and it is great.

If datamaster isn't talking, disable handshake/ccm update or something like that. Its after you try to strt recording in the box tat pops up in options. I don't hae it in front of me but will in a few hours to tell you exactlt Common problem with 93 LT1, as mine had to be disabled to work, on build 4.0 datamaster

Quote:
Just fixed a similar problem on a 92 with a memcal swap.
Pretty much same symptoms, speedo acting up, ASR light coming on from time to time and limp home mode.

Any members in your club with 92 or 93 Vettes to swap memcals? Is yours auto or stick?

well, since I don't have the IP related problems, nor do I have any of the communications related problems, I am going to have to hope that my memcal is still ok.

God, where does one even find one?

Might as well tell the shop to check the ground connections. There is one on the block just above the oil filter and the other one is the driver's side lower transmission mounting stud/bolt.

Thanks for the ground locations,

As far as the memcal goes I don't believe I can just switch with any stock one.
I have an Ed Wright chip piggybacked on it.

I have an procharger and bigger injectors etc. and I was told by John at FIC that it would run way to rich if I did that and foul out my plugs.

The ECU was sent with the memcal and we were told it checked out with no problems.

I was told that the rebuild shop sent a brand new ECU after the shop had problems with the first two rebuilt one.

I will ask if it was a GM ECU.

On second thought I can just piggy back Ed's chip on another memcal.

I don't know why I said I couldn't do it!

I was going to say the alternator because I had a similar issue awhile back. It's free to get it checked. Also check the battery cables while your at it but doing the grounds like suggested is a good start to.

I don't belong to any club but I guess I should.

My car is a 6 speed.

Thanks 95 Vette for the ground locations.

Any update on the problems?

Quote:

No need to be a club member. I will be blunt: most club members are more concerned with waxing their Vette's and having fund raiser breakfasts.

Status. I see on another forum Herb found the issue, sort of. Went to stock and eliminated the DELTEQ. I am curious as to what part on the DELTEQ was tested , how it was tested.

I would be curious, too. I suspect some of the DelTeq can be tested with a TECH II... but I am not so sure about the optical interface.

I have never heard anything bad about either the DelTeq or the LTCC. Period. I have had my LTCC for 8 years and 60k miles and it has been exceptionally reliable. I can't account for serp belts that explode, taking out harnesses... Or me screwing up the o-ring seal...

Steve40th is correct.
This is the 4th day without any problem.

After everything that could be checked on the Delteq checked out ok including trying a new Caddy module the car still acted up at times.

So,the owner said he was pulling off the Delteq and going back to stock.

Plugs,plug wires,Module,coil etc.

It would have been nice to know what specific thing was causing the problem.

Now I have the drivers side valve cover bolts leaking where the Delteq module & coils were.

Strange since they didn't leak when the module was there.

I'm trying to find some nice covers. I like the polished Chevrolet & bow Tie look but I can't find any that have the oil fill opening and the hole on the side like the passenger
cover.

Anyone know where I can find some?

THANKS
HERB

You mean where the oil vent hole is on the side of the cover? I am pretty sure that combo doesn't exist. You will have to adjust the fitment.

As for the problem, I am glad it's ok... I assume it's the same optispark?

My ugly problem has been fixed, too! It was the Dynaspark. I had it rebuilt and it's been running great for the last 5 days!

It's not the same opti that it had when the problem first started but when it was changed it did not cure the problem until everything else was changed back to stock.

I guess your right about not finding the side hole on the valve cover so I ordered the GM performance Proform covers.

ok, good. My problems were caused by a bad Opti, so I had to ask the question.

Glad to hear your back on the road! I am rather surprised the DelTeq caused this, tho... Unless it is somehow faulty or has a bad coil.

I would like to test your opti box from delteq. Not many have ever failed, but coils and modules have on Northstars, where these icm's and coils come from