Hammerhead69

My ‘’89 with the L98 has just started to randomly shut off with no warning. I was going down the road the other day & the engine just died like the switch was turned off. I think it’s something electrical since the radio quickly went off & came back on but all the presets were erased. I just put it in neutral & cranked it back up kept on going. Does anybody have any idea what might be happening?

Y-bodluvr

Could be something as simple as a LOOSE and or corroded battery connection make sure the terminals are clean and if the bolts are really old you’re better off just replacing them they’re like $2 for new ones Also make sure the battery is BOLTED down some movement can shut the car off if there is a bad connection being that your radio shut off lends me to believe it’s a charging problem and not an ignition..

Hammerhead69

Thanks for the reply. The digital voltage display showed 17 volts right after I started it back up & then almost immediately dropped back down to 13.5 volts.

Y-bodluvr

check the wires/connections going to your alternator too...

vader86

That it came back on at all with eliminated presets suggests battery connections to me. Remove the side panel, of course make sure the battery conneection is tight, and run the ground cable to ground to make sure thats tight.

Hammerhead69

Let me complicate it a little further....lol....When I got home I left it idling in the driveway & then checked the tightness of the battery cables. The negative was a little loose but when I pulled it off the battery the car continued to run.

Y-bodluvr

not a good idea for your alternator or computer :

pacoW

my '96 runs with the battery disconnected. If I turn the car off that way then I lose all presets (complete power loss). I would check all chassis grounds that you can get at starting with the bigger ones. You may want to just tie in a temporary addition ground wire to see if the problem goes away.

ctmccloskey

First: You should NEVER EVER run a MODERN car without a battery hooked up to it or you will toast a lot of expensive parts. Disconnecting a battery ground while the engine is running is almost as bad as disconnecting the positive cable while running. I have seen where lots of folks claim they can disconnect the battery when the car is running without problems. I don't and will never try to run any vehicle without a battery wired into the system

Check the wires going to your Starter, sometimes the ground strap or even the 12 Vdc power wires get loose. Another trick that is not likely to be a problem on your car, check the output of your alternator for "Alternating Current", I have seen alternators with a bad bridge diode send AC to the battery and worse yet to your ECM. AC going to the ECM is not good and will make all kinds of problems. It actually happens more often than it should.

Check your ignition switch as they do fail as well, not very often. I just replaced the ignition switch on my 1968 C3 as it wasn't sending power consistently out in the "run" mode.

Another possibility is that your Ignition Controller (inside the Distributor) is starting to flake out as they also will intermittently just shut down and after cooling off for a bit will restart and run. Once I had a broken 12 Vdc Power wire connector on the distributor , every bump or pothole would make the connection break loose for a second or two and then pop back in action. A fifty cent Crimp on connector solved that problem.

Being an Battery nut I can tell you that on these Corvettes like my 1988 have serious corrosion potential at the post near the battery where the power is distributed. I recently looked at the (Fusible Link) post after 5 years and it had corrosion on it again. I took out my wire brushes and cleaned the connectors and then reassembled the stack of ring type connectors that feed the Fusible links our cars depend on. I would clean every battery connection and alternator as well. When people look at the lead connectors on the battery cables they always look fairly okay, 90% of the time there is corrosion where you don't see it. Remove all connections clean them and then re-assemble them and spray them with battery terminal spray and they will stay cleaner longer. The best part of clean battery connections is that all the accessories were once again getting full battery voltage instead of the 2-3 volt drop I had previously.

Do you have a scanner that you can monitor your car with? That might help if you could watch what is happening when it shuts off. Intermittent problems are frequently solved by keeping a laptop in the car connected to the OBD port. That method has solved many a problem for me as when I hit the space bar on the laptop it recorded 10 minutes before and after the event. It turned out that the problem I had been chasing was a flaky 02 sensor and I cought it live on the Laptop,. The GM mechanics were impressed when I showed them exactly when the 02 sensor cut out, I had 20 plus pages of data and the mechanics said my laptop provided more information than their equipment. I only showed them after they agreed not to kill my new Cars warranty.

I wish you the very best in getting rid of this problem you are having with your Corvette.

Best Regards,
Chris

Hammerhead69

Thanks so much Chris.

KyleF

Once the car is started, the battery is a load on the charging system just like everything else. The car runs off the Alternator, not the battery.... modern alternators are regulated. There is no reason for a car not to run once started if you disconnect the battery. Battery problems affect starting not running.

The other suggestions about the grounding, alternator... all good things to follow up on. Coils/ICMs are also effected by heat and vibration and a good avenue to follow.

However, a bad battery constantly pulling on the charging system can cause other components to fail... and I am not suggesting that pulling your battery connections is without consequence long term... I am just saying that your systems are not designed to constantly run off the battery and if the battery would become disconnected, it will not cause the car to immediately shut down. It can run without it.

desertguyj

Definitely a battery cables and associated. Double chek terminals inside the lugs, too. and all grounds. And positive lugs