Hello all, this is my first time here, and my first corvette. I'll get right into it. I'm building a drag car. I purchased a nonrunning base model 93. Eventually I'm going to run it on a stand alone ecu but I'd like to get it to fire up for now.

I could care less about keeping the factory ignition cylinder. I'm just going to put it on a button. Here's where I'm at (the starter never engaged to begin with). I can manually engage it by jumping the solenoid or putting 12v to the purple wire on the starter relay with a power probe. So starter is good. Key in run position, jump starter still won't fire, I think the injectors aren't running.

So I'm thinking VATS related? I have no way of knowing if this is the original key. I went through all 15 resistors waiting 5 minutes between each. Still won't engage the starter off the key. Just to be clear, running the starter isn't my issue. I can run it from a button. I'm more concerned about VATS not letting the injectors fire. How can I verify this is the issue? What are the next steps I can take to start narrowing down the problem. Thanks ahead of time, I'll be as involved as possible in this thread until I figure it out and will post a solution. For anyone else who may be here.


Also edit after the fact, forgot to mention. The security light doesn't come on not solid not blinking just doesn't come it was never on from the start, I assumed the bulb is burnt out. Not sure if this info helps.

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First you need to expand your wait time 5 minutes is too short it's closer to 12. I have heard it argued 9 and 12 but I think the Interragater tool I used at the Dealership did 12 minutes

 

Understood, thank you I'll do 12 and report back. Will take a few hours before I reply next.

 

Unfortunately even give it a moment or 2 more to be safe, also since you have a key start with it's value. It wasn't uncommon for the Contacts in the cylinder can get Shakey

 

5 minute wait for a 1993 (or any mid-1990-1996) is more than adequate. The only "12 minute" wait was for early 1990s after the third 'wrong resistance' attempt.

VATS disables the starter, and it also inhibits fuel injection. VATS does not inhibit spark or fuel pump operation. The Fuel Enable (FE) signal is sent on the UART data line to the ECM, and the ECM sends an "acknowledgement" back to the CCM that it received and processed the FE. There are codes in the CCM associated with key resistance, FE, and the "handshake".

Is the SECURITY light on SOLID with the key in RUN? (Not "flashing" with a door open.) If yes, the resistance was not correct when the key was turned to RUN, and VATS is active.
^^ Ok, I see that the SECURITY light doesn't come on. There are (3) fuses for the CCM which controls VATS. LCD 5A, A/C 10A and CCM 10A. If any of these are open, the CCM will not power up and process VATS.

Does the center LCD speedometer light up and display data with the key in RUN? << This is also controlled by the CCM.

If you can get the LCD to come on and the SECURITY light to flash, you can use the onboard diagnostics to display codes and VATS status.

> Is the Service Engine Soon light on with the key in RUN? It must be, or the ECM is not powered up. If = NO:
> Does the INFT REST light flash a bunch of times when key is turned to RUN? If = NO, check the AIR BAG fuse. If it is blown or removed, the ECM does not receive power. The engine will not run if the AIR BAG fuse is open, or if the DERM (air bag module) is unplugged. (It should still crank.)

Read through this thread from January. There is a lot of information re VATS specifically for the 92-93. (The 92 particularly, and the 93 share the same problematic ECM that can cause a myriad of no-start, driveability and "VATS" related issues.) Unfortunately, the OP in the thread hasn't come back with the conclusion or final disposition of what it was.

EDIT: You have a 1993. I seem to always forget that the fuse panel changed significantly for 1993. The fuses I cited above for the CCM are for a 1992 which is what I have an FSM for, and the year that "VATS" discussions usually involve. I don't have a 1993 FSM. I'm sure there are still 3 fuses for the CCM, but I don't know how they are labeled in the panel. Turn the key to RUN and check every fuse in the box by probing the test holes to ground. If you get power in one hole, but not the other, that fuse is open. If there is no power in either hole, that circuit probably isn't powered, or the fuse has a bad connection to the powered side.

 

Thank you for the detailed suggestions. You brought to light some good points I failed to mention.
1. My center lcd screen is not powering on could this be an indicator the CCM is faulty?
2. I did a continuity on every fuse with my Multimeter both inside box with the small fuses and 2 outside boxes with the big fuses (all fuses had contunity and none missing.
3. I am getting spark, and I do hear the fuel pump run when ignition is on.
4. I pulled the airbag and put on a different steering wheel. Could this be the reason the starter isn't cycling?
5. The service engine soon light is on with the ignition in run
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[QUOTE=ItsYak;1609450629]Thank you for the detailed suggestions. You brought to light some good points I failed to mention.
1. My center lcd screen is not powering on could this be an indicator the CCM is faulty?
Possibly, but not likely. My guess is that the CCM isn't powering up or it is the cluster or LCD itself. If you can get the SECURITY light to come on, and the LCD is still blank, it could be the LCD which do have 'age related' problems.

2. I did a continuity on every fuse with my Multimeter both inside box with the small fuses and 2 outside boxes with the big fuses (all fuses had continuity and none missing).
Continuity is not the same as testing for voltage. Put one lead on a good ground. Put the key in RUN. Use the other lead to check every test hole in every fuse for voltage. Voltage in only 1 hole is a bad fuse.

3. I am getting spark, and I do hear the fuel pump run when ignition is on.
4. I pulled the airbag and put on a different steering wheel. Could this be the reason the starter isn't cycling?
5. The service engine soon light is on with the ignition in run.
The ECM is powering on. Only if you disconnect the DERM would the ECM be affected. The ECM is powering on because the fuel pump runs and the SES light is on.

Recheck the fuses using the voltage method. If you can get the CCM to power up (SECURITY) and the LCD working, you can use the onboard diagnostics in the other linked thread.

The inst clusters are known to develop bad connections and traces on the board. These maladies could cause the SECURITY, LCD, and other problems.
> Does anything work on the cluster or 'halo'? BRAKE warning with park brake set, green arrows, the back lighting in the LCD, or is the screen completely dead?
>The CCM controls the blue high-beam indicator. If the green arrows work with the turn signals, with the key in RUN, does the blue light come on with high beams? If = no, this is another indication that the CCM is not functioning.
> The CHANGE OIL indicator should come on for the 2 second bulb test. It is controlled by the CCM.
> Courtesy lights are controlled by the CCM. If courtesy lights come on with the headlight switch dimmer paddle, but not with the doors, this could be a CCM issue, but the courtesy light circuit is kinda complicated.

And you have verified that there is a CCM installed?

 

[QUOTE=IHBD;1609450837]​​​​​1. Yes, the ccm is installed (silver box beside driver right knee behind radio.
2. All I get in the halo ignition on is door ajar when door is open, brake when e brake is up, and check gauges. Nothing else. No blue high beam, no green signal arrows, no change oil during 2 second bulb check, no security.
3. Courtesy lights do come on with dimmer not when door is open

I did a voltage check on all fuses attached is a photo of the ones that display no voltage with ignition on highlighted in yellow.

Also, I disconnected the harness going to the clock spring because I don't need a clock spring anymore. Surely that can't have anything to do with the vats problem. The harness I removed is shown in this photo below.

 

Every one of those (5) fuses in a row is supposed to be hot with the key in RUN. Note that one of them is CCM1!

That row is fed directly from the ignition switch on the orange wire at the switch. The hot at all times feed to the switch comes from Under Hood "Ignition Fuse 7" which is 40 or 60 Amps depending on which page I look at.

You could have a bad ignition switch, but doubtful. More likely a bad connection of the orange wire at the switch. Or there has been or is an aftermarket Remote Start system that has compromised this wire.

Try this: Turn the key to RUN. With a jumper wire, jump the left (sitting facing the fuse box) hole on fuse 16 to the right hole on fuse 8 stop/hzd. This should energize the entire 'dead' row. The CCM may come to life, and hopefully the LCD as well.

I say may because no CCM functions with the key OFF suggests that there is no power to the CCM from fuse 35 or 39. OR the ground for the CCM is open. The CCM grounds at the RR of the engine on the upper bellhousing bolt. Blk/wht wire.

It's looking like there are multiple problems. Why was this car sold as "non running"? What is the history that led to the PO 'giving up'? What is the general condition of wiring and things? Is this car a basket case with **** hanging out of it everywhere, or is it generally intact? Sorry for all the questions, I can't see it from where I'm sitting at my desk in California.

 

I did some more digging, I jumped the fuses, still nothing. It gives 12v to the rest of the row but the right side of 16 is coming back with 0.81. Still no new action on the display or any other lights.

What I also did in the meantime. Is drop the column down a bit to get more access. The orange wire on the ignition switch reads 0v key off 12v key run.

I'm going to check the ground you mentioned in the morning when I get it on the hoist.

I wouldnt label this car ragged out defiantly needs some time put into it. It seems to be in good mechanical condition, I pulled the valve covers, checked the rockers, it sounds healthy on the starter. I got it for $600. Only non factory thing I can see is a sterio. Which is obvious wired wrong, previous owner passed away so I can't ask questions but it powers on with ignition off. It also raises the antenna randomly. Wiring issues definitely. But I'm willing to keep at it.

 

Also, side quest. But does anyone know what this does. Left side of the steering column you push and makes an tactile click. Wires coming out of it appear to be going to the side of the halo where the lights aren't working.
Thanks

Edit, it's the high beam switch the rod for it is just missing. Duh.
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Ok update. I was able to get the green turn signal indicators to come on. The way I did it was a serious shot in the dark. I didn't get the screen in the halo to turn on yet but I feel I'm on the right track. I took apart the turn signal switch because it has a copper bar inside that connects a bunch of different wires together and a spring and some other things. I don't know what all these wires do so I was nervous about randomly jumping circuits together. (I have a replacement coming tomorrow morning)
I removed the copper junction and placed 7 individual jumper wires on each soldered terminal. I jumped one to another (this is the shot in the dark because I don't know what controls what). The turn signal came on. I didn't go any further, I didn't want to risk burning something out before the replacement comes.

​​​​​​Below are two pictures, one of my jumper wires on the turn signal switch and one of the copper bar that seems like it's supposed to join terminals by resting on top of them.

The question for someone more knowledgeable than me. Because I forced the green flashing arrows on is this a good indicator my ccm is functioning?

 

That yellow thing is the turn signal switch. With it unplugged, the turn signals won't function.

Not at all. The green arrows are not controlled by the CCM. They are just dumb light bulbs wired in parallel with the front turn signals. Lt blue (left) and dk blue (right) wires. My asking about the green arrows' function was to ascertain whether the cluster was plugged in, and if it had a ground. If yes, then the blue high beam check would be valid for the CCM because the blue indicator shares the same ground and connectors as the green arrows.

Regarding the orange wire at the ignition switch: That wire goes directly to the row of 5 dead fuses. If you have power at the ignition switch orange wire but not at the fuses then the wire is interrupted. I mentioned in my earlier post that Remote Start installations interrupt this wire. Look at the orange wire; look at the harness. Are there any non factory butt splices or add-on wiring or equipment?

 

Update. I took your advice and inspected the whole harness inside. I got sick of guessing and squeezing around so I pulled the whole dash. Finally, good visual access to everything I should need to see. The harness isn't cut up or mangled anywhere. One non factory splice has been done on the thick red wire coming into the firewall left of the brake pedal (first picture). Whatever accessory previous owner was trying to run from it no longer exists. The 3rd leg of the splice has been cut off.

Second order of business. Follow the thick orange wire from the ignition switch to the fuse panel. Here's what I found (second picture) the orange wire is actually running into the row of fuses below the dead row. Getting a good 12v reading ignition in run. 0v ignition off. I'm looking at the dead row now. The wires running into the ccm3 fuse 16 are green (right side looking at panel) and yellow(left side looking at panel) I'm gonna keep pressing on but I can't seem to figure out how that dead row is supposed to be getting voltage.



Also, with the dash out what are some other things I can test. (I don't see any aftermarket remote starts. The only thing I can find related to that are two lectron boxes above the hvac controls that appear to control keyless entry.
Thank you for your involvement in this. It's helpful bouncing ideas around.

 

Ok, I'm sorry for wasting your time and everyone's time for that matter. The harness on the passanger side is absolutely molested. I didn't notice it a few hours ago because it was wrapped up well.
I'm not joking when I say there's literally duct tape and solid core house wiring crimps holding some of these together. I've never seen anything like this, I'm compleatly amazed. Going to take some photos just so you all can see why I was so confused.
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It just gets worse and worse the more wrap I cut off the harness. They are all held together with sticky old gorilla tape. I don't know how this thing hasn't caught on fire. Does anyone know why anyone would ever do this?

 

Those are factory splices. That is factory "gorilla tape". That is the way all GM harnesses were spliced from the mid 60s through at least 1996, which is the newest GM harness I've worked on. Those splices are very reliable and robust. I've never found one with bad connection. The biggies for wiring damage are rodents, floods, and fire. And people doing electrical work that they aren't qualified to be doing.

 

In the far left, bottom of the frame, what is the module or connector with the white and gray wires in it? Those aren't factory splices, but looking at the wire colors more closely, it looks like the connector splices for an aftermarket stereo pigtail. Actually, I've seen a lot worse for aftermarket splices.

 

[QUOTE=ItsYak;1609452454] Follow the thick orange wire from the ignition switch to the fuse panel. Here's what I found (second picture) the orange wire is actually running into the row of fuses below the dead row.
No, it is not! Look again. The orange wire is to a buss that feeds all 5 fuses in the row. The individual circuit wires are all brown, and are above the buss.

Getting a good 12v reading ignition in run. 0v ignition off. I'm looking at the dead row now.
That's correct. It's very unusual to have an entire buss test dead. I'm now wondering if your test procedure is flawed. Like the ground you used wasn't really "ground"?

The wires running into the ccm3 fuse 16 are green (right side looking at panel) and yellow(left side looking at panel)
Again, no they are not. Look again. The green and yellow are on #6, RH ILLUM which is above CCM 3. The brown wire below the circled yellow wire IS the wire to the CCM from CCM3. (I looked it up in my FSM and confirmed that green and yellow are indeed Illumination RH.)

I'm gonna keep pressing on but I can't seem to figure out how that dead row is supposed to be getting voltage.
Through the orange wire!

I now think there probably IS voltage on those fuses and your testing is flawed. The orange wire and CCM3 tell the CCM that the key is ON. Because the SECURITY light doesn't flash with the door open and the key OFF, there is either no power to the CCM from CCM1 and CCM2 which are both hot at all times, or the CCM is bad.

Also, with the dash out what are some other things I can test.
Before I'd start cutting up the harness, I would remove the CCM and test at the connector for power, grounds, and continuity to things like the SECURITY light. You really need an FSM for the pin outs, and frankly this level of testing may be above your skill set. If the connector colors on your 93 CCM are green and gray, I'll take a pic of the pin-outs in my 92 book. Other than the 3 wires for the PKE in 93, everything else should be the same as the 92 which I have an FSM for.

(I don't see any aftermarket remote starts. The only thing I can find related to that are two lectron boxes above the hvac controls that appear to control keyless entry.
Those are the PKE and the cruise control module.

Please. I told you what the wire colors and fuses were. Then you just missed looking closely enough and jumped to conclusions that are incorrect. It takes time to research this stuff and write responses and corrections. (I've been working on this post for 45 minutes. I have two FSM in my lap.) I'm human and can make mistakes. (Ask arbee or WVZR). But not so far in this thread. Please read carefully, and double check yourself when your findings disagree with what I wrote. Cheers.

 

You're right my intentions are not to waste your time. I incorrectly assessed the fuse panel and hastily posted after making an assumption the harness was tampered with, I've never seen a harness look like that before today. Moving forward I'll be careful and thorough. Your time and involvement means alot and I do appreciate the effort.

I'm going to get back after it tomorrow morning. I don't believe I have a false reading on the dead row because I probed the orange wire on the back of the fuse panel 12v key run 0v Key off. Same ground same time checked ccm3 row still dead ignition run. Now that I know the whole row is on a buss I'm going to look for any kind of damage to the bar, possibly the orange wire somehow isn't contacting the buss bar.

​​​​​I'll post my findings, and start checking wires from the ccm to the instrument cluster.