Solving Automotive No-Start Problems
Another common cause of a no-start condition is no spark, or no ignition. It’s the first thing I check for with a crank/no start condition. No-spark conditions can have a number of causes, but for starters, we need to know if we have spark when we crank the engine. As shown in the Crank/No Start video, you can easily check for spark with a spark tester or screwdriver. In fact, with a crank/no start condition, I often check for spark first since it’s usually the easiest thing to check. Just be careful, as some ignition systems pack quite a punch and you don’t want to get shocked during your testing.
If you find you don’t have spark, the next step is to determine if the problem is in the primary or secondary side of the ignition system. The primary side of the ignition system includes all the stuff before the ignition coil. This includes the igniter or ignition module, the pick up coil or crank sensor, the cam sensor, and the ignition switch itself. This varies greatly by manufacturer, so you’ll have to do a little homework to see how your ignition system is supposed to work, as well as how to go about testing it. The short of it is that the primary side of the ignition system tells the ignition coil when to fire. If it’s not told when to fire or it has a weak signal, then the coil won’t work right and you won’t have spark.
The testing for this varies greatly, but here are a couple of videos that explain a little more about the process of testing the primary side of the ignition system.
The secondary side of the ignition system is a little easier to diagnose since it mostly involves similar parts. The secondary side of the ignition system is everything after the ignition coil output. So if you isolate your ignition coil and you know you have spark coming out of it but it’s not getting to the spark plugs, you have a problem with the secondary side of the ignition system. This could mean a problem with the distributor cap, the rotor, the wires, or the spark plugs themselves. These parts include much of the secondary side of the ignition system.
With this type of failure, I usually just follow the chain from the coil to the plug to find the failure. Most times I find a bad ignition rotor or distributor cap, or occasionally a bad set of ignition wires.
Be sure to inspect the distributor cap and rotor for carbon tracking. Carbon tracking is when an electrical short is created by carbon deposits inside the distributor cap or rotor. These can be tricky to spot, but they look like tiny lines that connect different terminals inside the cap or on the rotor. This shorts out the secondary ignition and it never reaches the spark plugs.
I’ll go out on a limb here and say that if you have a problem with the secondary side of the ignition system causing your no-start, just replace everything: the distributor cap, ignition rotor, wires (HT leads, depending where you’re from), and plugs. These are maintenance items anyway so replacing them really can’t hurt.
One thing to note about Honda ignition systems: They HATE aftermarket parts. One of the first things I see rookies do when they get a Honda with a no-spark condition is to replace the entire distributor. This is wrong in so many ways. As you can see from the Honda No Spark video, it’s easy to find out if you have an ignition coil or igniter problem with just a test light.
Also, aftermarket distributors for Hondas are junk. Yep, I said that. Can’t tell you how many people have come to me with check engine lights and no-starts because they have an aftermarket distributor on their vehicle.
I’d go with a used Honda distributor over a new aftermarket any day. So don’t shotgun a distributor if you’ve got a Honda with no spark. Also, don’t replace the wires if they’re OE (Original Equipment). The OE Honda wires last pretty much forever; the aftermarket wires are mostly junk compared to what Honda uses. However, I have had quite a bit of luck with NGK wires, and if I needed to save some cash and get a new set of wires for my Honda, go with NGK wires.
Another issue you may run into on some Honda and Acura vehicles is a start/stall condition, or that the vehicle just stalls for no reason while driving. This is often caused by a faulty ignition switch. If you find this to be the case, you don’t need to replace the entire ignition lock cylinder. You only need to replace the electrical portion which is fastened to the back of the assembly. It’s not that expensive and fairly easy to replace. Just remove the steering column covers to gain access to the part. If you see melted solder inside the cover when you remove it, it’s likely you’re on the right track to a fix as this is one of the tell tale signs of a failed ignition switch. Here’s a video showing how to check for this problem on your Honda.
The last thing I’m going to cover for no-start conditions are mechanical failures. This covers a lot of possible issues, and I’ll touch on the main ones.
An engine needs to breathe, just like you and me. If it can’t breathe, it can’t run, just like you and me. An engine is basically an air compressor. It needs to draw in air, compress it, burn the mixture inside it, and expel the waste and spent gas. If there is a breakdown with the moving parts of the engine, it cannot perform these critical functions. This includes issues with mechanical timing, broken parts, or a loss of compression.
Let’s cover mechanical timing first. Most engines have a top end and a bottom end. The top end has the valves that open and close, allowing air to come in and exhaust to be expelled. The bottom end has the pistons that move up and down, helping to draw in new air, compress the mixture, and expel exhaust gasses. The bottom and top ends of the engine are tied together so that they work in perfect time. This is called mechanical timing. Mechanical timing is critical; it’s also exact. Most engines use a belt or a chain to connect the top and bottom of the engine. Some use a set of gears, but you don’t see that often.