TAC Tech => Electrical => Topic started by: P-Js_BLKBRRD on March 19, 2023, 03:40:22 PM
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To preface this post:
1) I know enough about electrical systems to be dangerous and so far have avoided getting zapped.
2) a FITECH EFI system is installed on the car.
The car has been sitting since late last fall and I needed to move it out of the garage to make room to bring my truck inside to do an oil change and tire rotation. So a couple of days in advance I put a trickle charger on to bring the battery up.
The day of maintenance rolls around and I pull off the car cover, hop inside (dome light come on), put the key in the ignition (buzzer sounds) and turn the key to let the EFI prime (without starting the car). After the fuel pump stops, I turn off the key and repeat the prime (have to do this a couple of times when the car has sat for a period of time). When the fuel pump stops I turn the key farther to start the car. Nothing happened - dead silence. Dome light isn't on and the key buzzer is silent. Headlights don't come on.
The battery charger shows the battery has a full charge yet everything is dead. What has happened? Where do I start looking?
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Check nuetral safety switch if an auto, or the clutch safety switch on manual, just follow the clutch pedal. This was my issue for a weird no start issue, grease gets old and the contacts get gummed up. Otherwise a loose wire, verify power is getting to the starter or where it doesn’t. Not the most mechanically informed person just speaking from experience.
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Sounds like a bad battery or badly discharged battery.
Do you have a digital volt meter? Ideally you have a meter with alligator clips or an assistant to hold the probes on the battery terminals while you do some basic troubleshooting. Static voltage on the battery with minimal load like door open and dome light on would be 12.5 volts or slightly higher. If your turn the headlights on battery voltage should be above 12 volts. With the key turned to start position battery voltage shouldn’t drop much below 10 volts with the starter spinning. I am guessing since the key buzzer doesn’t buzz and no dome light, battery voltage will be way down. It’s possible a long slow charge will bring the battery back to life. But if the battery has been discharged for months it’s probably no good. You can take the battery to some auto parts stores like Autozone and they will test and charge your battery for free.
If the voltage is above 12 volts and your dome light doesn’t turn on or no headlights you have corrosion on connections or lose connections.
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Thanks for the replies.
It is a 4 speed car and the battery is just a couple of years old. It was last run in November. I will pull the battery and take it to town to have it load tested just to be sure it is still good.
Everything was fine until I turned the key to start the engine so think there might have been a dead short in the starter that killed everything. I don't see any reference to a fused link in either the owners manual or the 1978 service manual so will have to do some more research. Just seems odd that the headlights/taillights don't even come on. They're usually on a separate circuit aren't they?
I'm not too good with electrical systems so will have to see if a mechanic friend can stop by and give me a hand. I'll let everyone know what is found.
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Sounds like a dead battery or maybe even a bad connection at the battery. I would pull the cables and clean then and hook them back up after test the batery with a volt meter (just to see there is voltage there).
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All my old cars do this occasionally. It's caused by corrosion on the battery cables.
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A meter is a good tool to help determine where you have a problem. With a dead short from the starter you will get a very large spark when connecting the battery. If the battery is not dead, you have a bad connection or open connection. As mentioned before a badly corroded connection will give you the same symptom as not having the battery connected. I have seen battery cables that don't necessarily look corroded but are. The plastic insulation could be hiding the corrosion. This most often is in the terminal ends where they attach to the battery.
The positive battery cable has a heavy gauge wire that goes directly to the starter motor, no fuse there. There is also a much smaller wire (maybe 10 gauge) that runs to the output post of the alternator. On that post of the alternator, will be another wire that runs along the rocker arm cover back to the firewall where it attaches to a large harness. This is where everything other than the starter motor gets its battery power from. The fusible link is usually in the area of the rocker arm cover. Both ends of the link are usually wrapped in electrical tape. Some earlier cars may have a fuse coming right off the alternator instead of a fusible link.
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a badly corroded connection will give you the same symptom as not having the battery connected
Now, in my experience, a teeny tiny layer of invisible corrosion will give you the same symptom as not having the battery connected. The symptom is initiated by the engaging the starter. 300 amps go through the corrosion for a millisecond and it's all over.
All my old cars do this, and they always have.
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Visited with my mechanic friend on Thursday and he echoed several of the probable issues all of you have brought up. The more we talked through things he kept coming back to the battery being bad. So yesterday I raised the hood and disconnected the battery cables. The negative terminal was clean but the positive terminal was caked with corrosion. Pulled the battery out of the car to have more room to clean the terminals. Then put the battery charger on it while I cleaned up the cable ends. I really dislike the side mount terminals as they hide any corrosion that may develop and are a PITA to clean. When I first connected up the battery charger the meter read 90+ percent but by the time I was done cleaning the cable ends it had dropped to 25 percent and the charger was very warm. So guessing the battery is indeed bad. So sometime this week I'll take it down to my mechanic's shop and have him load test it.
I'll report back on what ends up happening.
Thanks everyone...!!!
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You probably know this already, use a mixture of baking soda and water with an old toothbrush or brass brush to clean both the terminals on the battery and the cable end. You could still have internal corrosion on the battery cable, yet it will look alright. Measuring voltage drop at the battery end against the other end while under load will tell you if your cable is bad.
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Today I took the battery to my mechanic friend's shop and he checked it out. His test determined that the battery had failed internally so I took it back to the NAPA store I bought it from. Since the battery was less that 2 years old they replaced it under warranty.
Over the weekend I'll complete the cleaning of the battery cable terminals as suggested and install the new battery. Appendages crossed that the car will fire up.
Thanks for the replies...!!!
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Sorry to not have followed up. Got the battery cable ends cleaned up, new battery dropped into the car and connected. Hit the key and everything worked, except the engine wouldn't start. It turned over fine but wouldn't fire. Seemed like it wasn't getting any fuel. Last fall had a shop go through the TBEFI system I had installed and they corrected the plumbing of the fuel and vent lines (which corrected some other drive-ability issues) so thinking that allowed the fuel reservoir to lose its prime over the winter. So disconnected the power lead to the electric fuel pump, turned the engine over a few times to let the mechanical fuel pump re-prime the reservoir, reconnected the power lead and it fired right up. A couple of days later the weather turned gorgeous so got the car out on the road a couple of times. ENJOYED the drives...!!!