Folks.

My 1993 DelSol is experience something very strange.

The car starts fine. However, with a few seconds I loose all electrical power (tachometer drops to zero, heater fans stops, ect.) The engine dies a second or so after the electrical system shuts down.
I can immediately restart the car, but the same things continues to happen no matter how many times I restart the car.
The battery is new.

Any help would be greatly appreciated.

Thanks.
Ron

 

check and replace the alternator.

 

Thanks for the reply.
However, I cannot find anything in the Honda shop manual on testing the alternator if the engine is unable to stay running.

 

Do all the lights turn off too? If you are losing total power, the problem should be pretty easy to find. Id first clean all positive and negative terminals including but not limited to in the fuse box, the engine, body, and even remove the alternator itself and clean the mounting aluminum areas as the alternator ground is the body itself. When I say clean, I mean 400 grit sandpaper and go to town on any terminal you can freely unbolt and put your hands on. Make sure you unplug your battery first, of course.

I believe this issue is going to be near the battery or fuse block. You can hunt this down with a volt meter looking for voltage drop across circuits, but this concept is a little more difficult to explain, and id still start with cleaning terminals and contacts first anyways. Cars like clean power.

It also might be worth taking the alternator to a local parts store and let them bench test it. See if it loses power there too, but if you are losing complete power the issue should really be between the fuse box and battery.

 

Just remove it and have it tested at the parts store like Auto Zone for free.

 

Thanks, Faulcun.

I will check if the lights stop working.
The battery is new, so the terminals are clean.
The car will start every time, but dies usually a few seconds after it starts, when all the power seems to vanish.

I will check all relative electrical connections.
If that does not resolve the issue, I will take the alternator to a parts place and have it tested.

Ron

 

yeah thinking about it, It cant be the alternator. If you started the car, and disconnected the battery, it would still run because the alternator is providing power to the vehicle.

Likewise, if you started the car and disconnected the alternator, the vehicle would run off the battery until drained.

In your circumstance, the vehicle starts strong from the battery, indicating at the very least its not a charging issue.

If you are losing all power, it has to be a power distribution problem at bare minimum to the main relay which supplies power to both the computer and fuel pump.

The better scenario is TOTAL loss of power to the vehicle. This would put the problem to only a handful of components, beginning as discussed previously with the battery terminals/cables, and the fuse block

 

The holiday and warmer weather gave me time to do some more investigation.

After starting the car, power is lost to the ignition system, the heater blower fan, and the turn signals. Others components may lose power, such as the power windows and radio, but I don't think those have worked for a while anyway. The car has set through most of the covid time.
I can observe the tach going to zero an instant before the engine complies dies. That probably has to do with the momentum of the engine.
Lost of power to the heater blower fan and turn signals will sometimes be lost instantly, but occasionally remain for several seconds after the engine dies.

Power to the headlights, brake lights, and the key-in-the-ignition buzzer is maintained.
Trying to read through all the different wiring diagrams to determine a common circuit for the ignition system, blower fan, and turn signals lights is difficult at best.

Ron

 

Sounds like a key switch ignition pigtail failure.

 

I checked the terminals on the ignition switch, and all of them stay "hot" after the engine dies.

 

What I would do is pick a component with a simple circuit among the items that stop functioning. Id probably go with the blower fan. Focus on that component for your diagnosis and you should find the answer to everything.

 

If you can drive it or tow it somewhere Autozone can do a battery and alternator test for free. Start with that if possible.
If the car restarts fine then it’s probably not the battery, it seems like a bad connection or something with your key switch.

 

^^^ This sounds pretty on point.

You won't be able to inspect the electrical part of the ignition (key) switch and see anything of value. Replacing it would be more definitive. Typically vibration is the culprit but heat from current could cause the behavior you are describing. Heat from current pass through causes contact to lose connection, restart, contact returns to bad spot, wash rinse repeat.

Not sure if the main relay could act the same way, that was my other thought but could be way off base there.