Ok guys and ladies I am having an issue and I hope someone can guide me in right direction. I apologize ahead of time for the long post, but I want to include as much detail as possible. I have a 97 Vette T56 with a 402 stroker.

I just recently bought it, from a member here, and the previous owner rarely drove the car less than 5k miles in 9 years. The car has an Optima yellow top dated 4/16. He stored the car with a battery tender hooked up to it.

I drove the car 4 hours home without an issue except for a "weak" start after getting gas on the way home, but I didn't think much about it. Well then the following day I tried to start it, turned the key and NOTHING not even an attempt to start.

Ultimately I had the battery tested and the battery tested good. Reinstalled the battery and it cranked right up. I thought the issue was resolved because the negative terminal bolt(side post) was a little loose and seemed to be cross threaded. I replaced the terminal bolts and it cranked right up.

The following day again it was dead, turned the key and nothing. Unhooked the terminal bolts, hooked them back up, and it cranked right up. Ok so now, I had the same issue, unhooked then rehooked up the terminals, car cranked right up. A few hours later I tried to crank it and nothing, I didn't touch a thing and a few hours later, tried it and it cranked right up without hesitation.

Following day, I tried to crank it and NOTHING again, I unhooked it, hooked it back up, and it cranked right up.

I drove the car and when I went to brake the car died, according to the DIC the battery volts would drop to 11 or less, cranked the car right back up, and battery volts jumped back up to 12.0-12.3 or a little more according to the DIC. While driving the volts on the DIC read 12.3 or so, but when slowing for traffic, volts dropped to 11 or less then died, car immediatley cranked right back up. This happened at least 20 times, does anyone have any thoughts, I think it is some sort of loose connection. Any thoughts or advice would be appreciated.

Today I replaced the battery, instantly cranked up without hesitation. The battery volts on the DIC now read 13.4ish which is much better than before when it was only reading 12.4 then it would drop to under 11 and the car would die. But I now have the dreaded "low voltage" warning and codes for the EBCM and ABS. Does anyone have any suggestions about fixing this issue, I know if the entire thing goes out it is nearly impossible to fix or replace. With that being said what does it actually mean, does it mean I have no ABS?

I tried to clear codes but wasn't able to, I let the car sit a few hours, tried to crank it, and now the car is dead again and doesn't even try to turn over and start, the key does NOTHING in the ignition. Any advice from anyone would be completely helpful and beneficial.

Also to add, when I would reconnect the battery terminal bolts, there would be a slight spark and then I would hear an audible "tick" it seemed when I would hear the "tick" the car would start after it was all hooked up, but if it didn't spark and I didn't hear a "tick" the car wouldn't start.

 

Those symptoms could be a failing ignition switch. A common thread through your report is that after a shut down or a sudden failure to start, a new attempt to start results in a normal start and run. When the second ignition switch on my car began to fail, the engine suddenly stopped running at a stop sign but restarted and ran fine. For both of the two failed ignition switches on my car I saw low voltage on the DIC along with a slew of other warnings. This is because the switch contacts get burned over time and do not allow proper voltage to be reported on the DIC.

To determine real battery voltage, you must measure it across the battery terminals. A fully charged battery will read at least 12.6 V or slightly higher across the terminals. With the engine running, you should measure about 13 to 14 volts across the battery terminals if the charging system is working properly.

Proper battery side terminal torque is 11 foot pounds, many owners people do not fully torque the battery terminals. Since you have changed batteries it is unlikely that both batteries have shallow side terminal bores, but there have been reports of shallow side terminal bores in batteries and shallow side terminal bores do not allow the cable to be tightly clamped to the battery even though the cable bolt is properly torqued.

These symptoms can also be caused by the theft deterrent relay going bad and or the ignition cylinder key contacts or key being dirty and not making contact. First try a different key and or cleaning the key you are using. Also try spraying a dielectric cleaner like Break Free into the ignition cylinder where the key is inserted. Try changing the Theft Deterrent relay.

And, of course the failure to start could be the starter solenoid or starter going bad. Some have found that clonking the starter with a rod will allow a start if that is the case. If so, the car needs a new starter.

 

With the combination of a no start plus low battery charging voltage I’d head down to the starter solenoid and remove both the B+ from the battery and from the alternator...take a wire brush or emery cloth and clean them as best you can and also the solenoid stud. You can verify a bad connection there by taking your DVOM and putting one lead on the B+ wire at the alternator and the other at the battery positive terminal..seeing .2 volts there is good...you can do the same thing to check the negative side of the charging circuit...one lead on battery negative and the other lead on the alternator case...you should read about the same...you can put your DVOM on a 2 volt scale if it has one...do this with the car running !!..having just a bad starter you should not see low charging like you’re seeing.Forgot to mention you should remove the battery negative terminal which attaches to the engine block...it’s in that same area...every other year that’s part of my preventive maintenance program is cleaning all those terminals...not easy to get to but it helps !!

 

I will try these and check them and report back, it might be a while as I am headed out of town. Please keep the suggestions coming.

 

I had starting problems several years ago with my 04 C5. I squirted some CRC Mass Air Flow Sensor Cleaner in the ignition and no further problems. I now make this a twice a year process. Hope you resolve your issue.

 

I will try this, at this point I will try anything, but the car is currently on a speed density tune

 

Op, it’s a good idea to put all of your mods including this speed density tune in your profile...this helps us help you in a diagnosis down the road !!

 

Checking that the TDR "Theft Deterent Relay" is being energized is always a good place to start. It is located above the BCM in the passenger footwell area and is the Relay that sends power to energize the starter, you should hear it every time you turn the key to the start position. Many corvette owners have replaced the BCM to correct this problem, disconnecting and reconnecting power resets the BCM. Hope this helps.

 

How do I go about checking it? I read a post about "jumping a wire" what exactly does that mean and what is it or is not supposed to do?

 

**UPDATE**
So I cleaned the grounds, but I couldn't take the pin grounds apart and was afraid to break them. I changed the battery as I mentioned before, and it immediately started, thought issue was resolved.

Few hours later, car won't start, turn the key and NOTHING happens at all. Go out of town a few days and start messing with the car again. Nothing changed and volts on DIC reads 10.3ish, ultimately try to jump start the car, NOTHING. I leave the jump hooked up and after about 5 minutes, "security" begins flashing on the dash, horn beeps, and car starts very easily.

I will mention after the jump was hooked up for several minutes the horn beeped, then "security" was blinking as it should and the car started.

A few hours later I open the door, dash is blank, I sit in the car with the door open, try to start it, and nothing. I sit there for about 10 seconds, horn beeps by itself, dash lights up with "security" and the car does start.

After the car started, volts on DIC read 12.3ish while driving. As I drive when I touch the brake even at low speed to get out of my driveway, the rpm's drop and the car dies, immediatley cranks back up.



I am at a total loss of what to do. Any help would be appreciated, I am trying to include as much detail as possible.

 

As previously suggested, I would pull the Ignition switch and replace, or clean the contacts. There is a sticky on this forum that details how to disassemble the contact block. Have you also verified that your cars alternator is charging the battery. Very simple to measure charging voltage across battery terminals with car running.

 

Another update, I used a volt meter and the alternator is charging at 13.7 volts, the battery reads 13.7 volts. The fuses in the fuse box read 13.7 volts with the exception of if I remember correctly 12, 13, and 16. I know 16 is for the PCM and they all read somewhere around 12.5 volts.

I couldn't get it to start and I removed the negative battery cable, I reconnected it and during reconnection the alarm started going off, I put the key in the ignition and the car started right up, as I drove it it began dying again when I touched the brakes.

With the car running in neutral, rev the engine a little, touch the brakes and the car immediately dies.

I did have a tuner check it today and the column lock has been disabled. I am still at a loss of what to do next.

 

Just to check the voltage drop across the ignition switch set your DVOM to the lowest voltage setting...maybe yours is a 2 volt scale...run the car at idle and connect the red lead of your voltmeter to battery positive and the black lead to one of the 2 metal “nubs” on top of the PCM and fuel pump fuse (13)...should be around .2 volts or so on each one...what does yours read ??