Skip the auto shop - Our mechanics make house calls

Q: Truck will crank, but engine won't start - 1973 Chevrolet K20

asked by on

The old battery in my car would not hold a charge, so I replaced it with a new one. After installing the new battery, the truck will crank, but the engine will not start. I held a plug wire next to ground to test for spark, but there was nothing. I also used the same technique to test the coil wire - nothing. Next, I tested for voltage across the input wires to the coil. When the ignition engaged, there were only 4 volts. Next, at the ignition fuse, in the fuse panel, I tested for voltage and saw 12 volts. I know that from the starter solenoid is the only other direction that the voltage comes from. When I tested there, it was 12 volts going into the solenoid, however only 4 were coming back to the coil. My truck’s starter is a new one that I installed several months ago. Next to the distributor is a small capacitor-looking part in the same bracket with the coil. I don't know if this is a resistor or a capacitor. There is only one connection that goes to the coil’s back side connection. I have been researching for wiring diagrams but so far haven't found any. Could you please give me whatever help you can for these problems?

Hello there, thanks for writing in. The wiring diagram for the ignition system of your vehicle is pretty simple. Power flows from the ignition switch to the coil. When the engine is cranked, the points open and close to create voltage in the coil secondary windings. This creates the high voltage needed to fire the spark plugs, which is sent to the distributor.

If there is no spark, suspect a faulty coil, coil wire, cap rotor, points or distributor. The wiring between the ignition switch and coil could also be bad. A faulty starter will not prevent the engine from getting spark.

It sounds like you’ve already spent a lot of time on this issue; if you’d like further assistance, consider having one of our certified automotive technicians come to your home or office to diagnose and repair your vehicle properly.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: My Expedition vibrates a lot when stopped at a slope

Hello and thank you for your question. This symptom is not related to the engine but rather the transmission. If you drive the vehicle around and the engine runs just fine, then either the engine oil is low, causing the...

Q: car not accelerating properly, only gets half way to the speed

Many different things can cause the car to lack power. Most of these will be seen with a Check Engine Light to indicate there is a fault. The most common issues involved in this scenario are problems with the fuel...

Q: Electrical issue

Thanks for writing in about your 2006 Saturn. It looks like you've inspected all of the usual suspects, but one item you might want to look at is the battery temperature sensor. Battery temperature sensors detect the temperature of the...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...