What to do when your car won't start: for fuel injected and carbureted cars
First, let's look at the obvious: the battery. When the battery is run down, but the headlights seem to shine at full strength, usually the starter makes click-click-click noises. That usually means you need a jump start. Of course, if the headlights are dim or off entirely, the battery is the most likely candidate.
A clicking noise from the starter indicates (usually) a dead or dying battery, and (sometimes) a dead starter. This may be a common problem on 3.3 family engines as they grow older. A single click from under the hood on an attempted start could mean a bad starter relay. Jump starts do not always work; poor quality cables can prevent enough power from being made.
One reason why the battery might die is a constant draw of power from the tachometer drive board, in early 1990s cars [see the fix]
If the battery's in fine fettle, there are a few other problems that could cause your car to refuse to start. First, check the gas.
One contributor noted (this relates to older cars, as newer ones do not have distributors or rotors):
A perfectly running, recently tuned car died and would not restart. It turned out to be the ignition rotor. The bad rotor was only a couple weeks old and looked perfect. There was spark at the spark plugs so that test alone is no indication. There were no codes set in the computer and I tested everything in the ignition and fuel system. I discovered it was the defective rotor, partly by luck.
It is impractical to carry all kinds of spare parts in your car, but carry at least a rotor ($8) and probably a cap ($10) as those are cheap and very easy to replace, under 5 minutes. Your rotor, no matter how new or perfect looking, can fail any time and leave you stranded, as it did to me. It is your $8 insurance against at least one reason why you might need a tow.
If you car is not starting or stalling and you are about to pull your hair out, try a new rotor and a new cap, even if the ones in the car are very recent. It just might do it, and it is a cheap fix.
This also emphasizes the need to really dig into the basics of ignition before proceeding with more exotic tests. In my case, cap, rotor and wires were brand new, but don't discount the possibility that some of those may be defective, even if they look perfect. Some tests can be unreliable and insufficient, as I learned from the spark plug test that looked okay despite the bad rotor. Next time you do your tune up, keep your old cap, rotor and wires, that you know are working, to try in case something is wrong and quickly eliminate many possibilities.
If the engine was wet, dry it, separate the wires, and try again, Use silicone spray or "wire drier" and, if that works, replace your wires with really good ones ($25-$60 mail order). Dan Stern recommended Whitaker's Multi-Mag, which look like the original wires, but uses the spiral-wound construction of modern, high performance wires: lower resistance, but no irritating radio noise. They have a lifetime guarantee and don't cost more than regular carbon-string type wires. The Slant-6 wire set (32605 for pre-1975) has the correct one-piece moulded plug boots. They are also sold under the Borg Warner/BWD KoolWire name.
Many have found that automatic-equipped cars would not start in Park, but will start in Neutral. Bill Watson suggested that the shifter linkage might be out of adjustment, very slightly.
The linkage from your steering column attaches to an "arm" that sticks out from the tranny on the driver's side (console shifters are similar). Get under the car while someone moves the gearshift linkage. This way you will be able to determine which way it goes when you put it into park.
What you do is place the car in park, loosen the bolts to the "arm", push the arm all the way in the direction park is engaged. Then push your gear level all the over the left - as far into "P" as it will go. Then tighten everything up.
The problem could also be the neutral safety switch, if it will not start at all:
To find the neutral safety switch, look for a small wire attached to your starter solenoid that leads down under the floor toward the transmission. You will find the neutral safety switch at the other end of it. [This switch may simply be dirty]. ... John Smith had starting problems, mostly when cold, on his 250,000 mile Dodge Spirit. He found oil in the neutral switch next to the transmission dipstick. Cleaning the connection seemed to fix it.
Fuel injected cars
Then check the computer codes - click here for instructions. Often, the computer will know what is wrong, but it is not infallible.
Next, turn the key and listen carefully. On most Chrysler cars, you can hear the electric fuel pump engage for a second or two as soon as you move the key from OFF to RUN (not START - it will still engage but you might not hear it). If you do not hear that, there may be a failed relay, fuse, or fusible link, or even a bad fuel pump. You might want to try testing your car for this before it refuses to start, so you will know whether you can hear it or not. (If you can fold down your rear seats, and you have a sedan or hatchback, do so - the fuel pump is in the back).
If the engine turns over, you may want to check for a broken timing belt. On many cars, you can peek in and see the timing belt directly. That is not the most likely problem. Most Chrysler engines can deal with broken timing belts easily, and without the loss of the valve train and pistons!
Ed Hennessy pointed out that the auto shutdown relay may be bad; if it is, the fuel pump and coil will not get power. For 1980s cars only, "Try feeding power to the fuel pump directly. Temporarily connect 12V+ from the battery to the positive terminal of the coil. That will back feed 12V to the fuel pump through the ASD circuit. If the pump runs, the ASD relay is bad." Do not drive this way. Replace the ASD relay. (Bob Lincoln wrote that this will not work on cars starting in the early 1990s, because the computer has to switch the negative terminal of the coil from 12V to ground to keep the relay open; energizing the positive terminal still leaves the negative terminal at 12V, so the relay won’t close.)
Try disconnecting the MAP sensor, which can cause a car to not start without setting any fault codes! If you disconnect it completely, the car may start, in which case it is definitely the MAP sensor.
Another common problem is the Hall effect sensor, which tells the computer where the engine is. This is moderately easy and inexpensive to replace (as is the MAP sensor.) Even cars with no distributor use Hall Effect sensors, on the block.
There is also an engine fuse which might have blown - along with various fusible links. Check the owner’s manual to find their location.
Dale Berry pointed out that old or bad spark plug wires, especially moist ones, can cause non-starting, and suggested that you check all spark plug wires, check for moisture or carbon tracing in the distributor cap, and consider excessive water in the gas. He also pointed out that a completely clogged catalytic converter and flooding could cause failure to start. Your car's owner's manual should have instructions on what to do if the engine is flooded (has too much gasoline).
A leaky fuel injector or weak fuel pump may also cause problems. To diagnose these, click here.
John Mastriano noted a common problem: when no electricity was at either coil terminal with the key in ON, but the engine still cranked: "repair the burnt-out fuseable link in the wiring harness next to the left shock tower."
In one case, a Power Ram 50 had no start after installing a new engine, though there was spark; the injector wasn't firing. MacMichael pointed out, “are you sure you hooked up the ground strap from the intake manifold to the firewall? —this occasionally gets forgotten after doing engine work." (Thanks, swalve.)
Those are the most common causes of not starting, but we are always open to feedback on more systems.
Cars with carburetors
On cars with electronic ignition (starting in 1971, but often retrofitted to older vehicles), check the ballast resistor. It's a little white block attached to the metal between the engine and the driver, with a single bolt; wires plug into each side. It's easy to replace and costs under $5.
If the starter makes a rapid clicking noise, your battery may be worn, even if you can see your headlights.
You can extend the life of your ignition coil by moving it to the fender or firewall, away from the engine, so it is not affected as much by engine heat. (High Performance Mopar tip sent by Erik Namtvedt)
“Shakercude” noted additional issues:
- The starter has a solenoid. These will get pitted and a no start will result. A separate part of the starter.
- You have a starter relay on the engine compartment. The connections to the relay must be tight. The battery wire leads to the relay and from the relay to the starter solenoid. These are a parts store item.
- Check the heavy gage wire from the battery (positive and negative). The negative must be clean and tight to the engine block. The positive is hot where it connects to the starter if the wire moves under the nut on the starter disconnect the battery and then tighten.
If your problem is the starter turns the engine over but the engine does not fire:
1. The connection to the electronic ignition could have a terminal in it that is worn out or a broken wire.
2. There are several connections from the ignition switch out to the ignition system, including the dash panel connector. It might be a good idea when the engine is running to just grab the wiring along the inner fender and move it around a little.
3. When the engine does not fire try turning the ignition switch to accessory and then all the way forward to start.
4. The distributor can have hair line cracks in it. This can be checked only when running by spaying a light mist on the cap. If you see sparks or the engine starts running rough it is the cap.