thires

4 years ago I have a 94 vette that runs fine when the weather is cold and on warm days before the coolant temperature exceeds 207 degrees. At that point the idle speed becomes erratic and surge, it also coughs and sputters at low speeds. I haven't had the car long and it been like this from day one. Several members of this forum advised me that it was probally the optispark. Not willing to change cams and not willing to replace a defective designed part with another defective designed part, I lived with it for a year or so till I replace the coil with a coil pack system. Taking the high voltage out of the cap took care of the problem.

As time passes I had a clutch cylinder leak inside the car that got wires and thing quite wet. I don’t know if this has anything to do with the problem but I’ll throw it out there. I replaced to cylinder and cleaned up the mess as much as I could. Not to much later I noticed that opening the drivers door no longer turned of the radio, and the door hatch release quit working as well. I checked the door ajar switch and it is operating correctly. So, I just ignored the problem. Several months (14-15) later the car started having drive-ability problems again. After some rainy weather (don’t if moister had anything to do with it), while accelerating on the highway the engine started choffing, the tach when erratic, blue-gray smoke came out of the tail pipe, and the engine died. While still moving down the road at 60mph, I turned to ignition of and back on (without any clutch action) and the engine started up and the rest of the trip was uneventful.

This started happening more frequently, usually after the car has been driven 4 or 5 miles. Now it happens every day after just a mile or two. Sometimes it restarts on the go and everything is fine. Sometimes it starts and immediately does it again. And sometimes I have to pull off the road and wait a while. I have determined that once this condition happens that even with the clutch disengage (no engine load) it will still refuse to stay started.

A few day after this started happening I do the restart on the fly trick and my hatch opens as I’m going down the road. And the “Passive Entry” light comes on and stays on. I don’t have a remote device. I don’t recall ever seeing that light before. Now it’s on most of the time. It goes out when I insert the key in the ignition but comes back on as soon as I start the vehicle.

Hear is what I’ve tried since the stalling at high to medium rpm problem started: fuel filter, fuel pump, optispark distributor, coil pack ignition module. The heads were worked along with new plugs and wires 1 year ago.

I’ve never seen a car die from 3000 rpms before, and start right up like nothing was wrong. The only engine code is 09, H62 – from what I can tell that is tach input missing.

Any possibility that the PKE module could be causing this?

Thanks

pcolt94

I don’t exactly know what to answer here but as far as the PKE goes, it pretty much controls the PKE light. There is not much else external of it that could affect the lamp. Proper operation is when the key is turned to on, the PKE light goes on for 2 seconds while it does a self test. So I would say if it never lit before and now it stays on the PKE receiver is defective. And no, it is not going to effect engine operation.

An FSM would probably help you so you can see what connects to what and how some things are configured. However I would check the fuel pressure with a gauge, look at the O2 numbers with a scanner, make sure the CHT is good and the digital temp reading on the speedometer looks OK and a general check out of some of the sensors, TPS, IAC under the hood. A scanner can also tell you the BLM fuel numbers and if it goes into closed loop.

thires

Thanks for your input.

I did the paper clip scanner thing. It’s a 1994 and the diagnostics system is not a ODB1 or ODB2. It’s some mix of the both. The car does show a code that the tach signal was lost or missing. Is there any benefit to getting a scanner for the car?

The problem is getting worse. The car is just not safe to drive anymore. I’m reluctant to take it to the dealer because I suspect that the opti-box is the culprit and the deal would not be able to fix that.

I’ve been trying to get in touch with the manufacture of the opti-direct system. I’ve email and called them on the phone. Their voice mailbox has been full for weeks. I wanted to try the opti-box just to rule it out before I turn the problem over to the dealer.

This weekend I’ll check those things you suggested. Thanks

L71Maynard

I'm having the same problem with my '92. It will die randomly and sometimes give the H62 in the 9.1 module but other times no codes are thrown. I've got 2 ECMs and it happens with both. The difference between my car and yours is that I have the Delteq Opti-Direct installed. It's been on the car longer then I've owned it (3 years now). I don't have anyway to pull realtime data so I don't know what's causing this.

The FSM for an H62 code doesn't help much. I've traced wires to the ECM and CCM and not found a problem. I've changed out the TPS, IAC, and coolant temp sensor (because I broke the old one) without any change in the way the car acts. I'll have to check the fuel pressure to see if it goes when the engine dies.

Anyone in the Denver metro area that would be willing to scan my car realtime?

Dave

thires

Dave, I too have the Opti-Direct system. After changing the fuel pump and fuel filter, I actually tested the fuel pressure. It checked good. I also check the TPI. They both checked good even while the car was going through its dying condition. I also put an oscilloscope on the ignition system. What I found was that the opti direct opti-box was losing its sync signal when the car would go though is dying spasms. Because Delteq is apparently out of business and I can't seem to find an opti-box anywhere, I going to have to change the system out.

I spoke to a once opti direct distributor last week and he recommended changing out to a LTCC system. He had a used system he would sell me for $800. Having just been burnt by delteq's proprietary out of business product, I am probably going to return to a stock system. At least if that doesn’t fix the issue I can take it to the dealer with some assurance that they can’t blame it on an after-market product.

Tony

pcolt94

You are technically right about it being a mix of OBD 1 & 2. But in practically it is a OBD 1 system. The on board diagnostics only display the OBD 1 codes. And a basic OBD 2 scan tool will not even establish communications. The Tech 1 or similar scan tool that was designed for the system will indicate an indication of “no OBD 2 codes”. I have created several OBD 2 codes by accident one day while I had the Tech 1 connected and saw the screen fill with codes. When I went back to see them it indicated “no codes”. The OBD 2 codes on the 94 monitors very little and not even worth mentioning or being really beneficial.

I would consider it OBD 1 for all practical purposes. It was the first year they started laying the OBD 2 frame work.

I can see what you mean by the voice phone mail being full. Unfortunately it does look like a sole source item with no other place to go. However someone is paying the phone bill and wondering if you have left you phone number for them to call back. I can see why you would want to revert back to the opti just to get it going again. Maybe you will get lucky and be able to get a spare part or a call back to at least know the possibility.
Best of luck.

L71Maynard

This is bad news, I didn't know they were out of business. This week I determined the same thing you saw and was going to try and get a new box. I didn't do the conversion but I guess I'll have to put it back to stock as well. Let me know when you get yours done. I'm going to have to order new plug wires and figure out how to route them to the opti.

Dave

93stroked

Are you sure Delteq is out of business?

BluRay

Considering it is temperature related I would check your coolant temp sensor. You can do this with an ohm meter. The details are laid out for you at alldatadiy.com My username and pass are on a thread in general or tech(can't remember), just do a search for "an offering for techs". It's not REAL likely since your issue kills the car. I would also be suspicious of the EGR valve having a bad spring, or being carboned open. The exhaust pressure can hold them open once they are opened by the ecm or even force them out of position. When the car stalls and the pressure goes away the valve will close on it's own allowing restart. A rather crude test for this is to remove the valve and place a dime under it. Then bolt it back down lightly against the dime to keep it from leaking. Go for a drive and see what happens. This may also cause an SES light depending on if the 94 monitors EGR flow.

You may also try just disconnecting it(the ECT sensor). This will of course set a code and engine light, but if you lose your issue then your on the right track. It should be located in the front of the engine(water pump) and have a two wire connector.

Driftmonster

I was getting the H62 code, and the car was dying randomly on the road, my gauges would go nuts.... ect. I have a '93, I installed an MSD optispark and all my problems vanished.

thires

I replaced the optidirect system with an all new original optispark system and it works fine now. Its all new original execpt I added a couple of vents in the optispark cap for the next time it collects mosture for whatever reason.

pcolt94

It’s great to hear the end of a success story. You should be good to go for a long time now. Take care of some of those other item now and just drive the car happier.