FAQ - My Honda Civic Won't Start - Read Here Before You Post
So, your 88-91 Fuel Injected Honda Civic won't start? Many people here had similar problems (including me), and I'll try to explain a few troubleshooting tips that might help you get your Civic running again. Even if your Civic is a bit older, or a bit newer - you might find some interesting informations here.
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Some, perhaps unknown, terms I'll be using here:
MPFI - Multi Point Fuel Injection - MPFI engines have 1 injector for each cylinder. Standard Civic engines have 4 cylinders, and so they have 4 injectors. Fuel to the fuel injectors is brought through a fuel rail which is connected to a fuel filter. Each injector has an electrical connector attached to it, which brings signals from ECU telling injectors when to inject gas.
DPFI - Dual Point Fuel Injection - DPFI engines have 2 injectors in the throttle body, one main and one auxiliary. Fuel to them is brought through a line from fuel filter to the throttle body - if injectors are pulled from a throttle body, they do not get gas. Injectors also have an electrical connector attached to them which brings signals from ECU saying when to inject gas.
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One of the first things you want to do when you have problems with your Civic is to check your ECU / ECM (Electronic Control Unit / Electronic Control Module) for error codes. It is a metallic box, placed under the carpet, below the glove box, where a passenger would usually keep his/her feet while driving. Pull the carpet down a bit, and you'll see it. There will be a circle on the metallic sheet, which is just an opening through which a red LED light can blink. When you turn the key to position "II" (when the Check Engine Light, Oil light and Battery light turn on, but you do NOT yet crank the car) the LED will blink once, as if it's saying "Hello there, I'm alive...". That LED will report any error codes it might have stored after the initial hello-blink. Error codes are coded with blinks as follows: number of short blinks = error code, pause = another error code is coming now. For example, if you're getting a "HELLO_BLINK-pause-blink-pause-blink-blink-blink-blink" it means the ECU stored error codes 1 and 4. Once all error codes are "blinked" (displayed), ECU will "reblink" them again. Notice that if you're getting something like this: "HELLO_BLINK-pause-blink-pause-blink..." it means that ECU has an error code 1 stored. If there are no error codes, then the ECU will just blink once and will not blink again.
After you've written down all your error codes, you can search online for an error code list. You can find an error code list on www.4thgenerationcivic.com
Now error codes might give you an idea as to what's going on. One of the very common error code you can get is 16. It means there's something wrong with Fuel Injection System. Now, don't go running right away, trying to replace fuel injectors. If your car is having a hard time starting in a hot weather (after being parked in the sun for an hour or so), or if you shut it down, go to the store, come back and it won't start, AND you check your ECU and see an error code 16 - you most likely have a bad Main Relay. It's such a common thing with Civics. Now don't either go running to the store to buy a new one. All you have to do is take out your old Main Relay, resolder it's joints, and put it back in. I did that to my car (it experienced the same problems I described above) and it's starting every time since I did that. Detailed instructions on how to "DIY (Do It Yourself) Main Relay Fixing" can be found here - http://www.markl.f9.co.uk/howto/elec...main-relay.htm
When you're done with fixing the car, have your negative battery cable disconnected from the car for about 20-30 seconds. It will erase the ECU memory of error codes. It will help you notice any new error codes once you see your car is having troubles again. To make sure error codes are deleted from memory, try checking for error codes when you connect the battery cable again. You should see less error codes then before (hopefully none).
Final note about checking your error codes: Many people will tell you that you should disconnect the negative battery cable for half an hour or more to delete error codes. Official Service Manual states you should only keep it disconnected for 10-15 seconds, so double that if you want to be safe and keep it disconnected for 20-30 seconds. I've tried it and 20 seconds work.
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Problems with starting your car might be caused by not getting a spark, not getting fuel or by your timing being off.
To check if you're getting fuel, the easiest way would be to have someone crank the car while you smell the exhaust. If you can smell gas, it's getting gas. Just a word of caution here - do NOT try smelling the exhaust of a working car. There is carbon monoxide in it, which can, if you breathe in enough of it, kill you. If a car is working, it is getting gas :)
If you're not sure if you smell gas or not, pull out your injectors (if you have a fuel rail and 4 injectors (all 1.6 liter Honda Engines are MPFI, only 1.5 liter DX is DPFI - if you have a DX, try pulling out the whole throttle body which is connected with 4 nuts to the intake manifold)) with the rail still connected to them (and electrical connectors connected to them too), pointing them to somewhere that will not ignite the fuel once they (if they) squirt gas out, and have someone crank the car while you look if gas is squirting out. If the gas is not squirting out, you now know that your car is not starting due to not getting gas to the injectors. It might be caused by clogged fuel filter, clogged fuel lines, non-working fuel pump (make sure you check for Main Relay before you go out to buy a new pump, because Main Relay gives power to the fuel pump - if your Main Relay is not working fine, and you DON'T check it first - you might believe that your fuel pump is not working, and be amazed that your newly bought fuel pump is not working either, all because of a Main Relay) or no gas in the tank (a long shot, but hey... ). If you are getting gas, then connect everything back (injectors into the intake manifold, or throttle body to the intake manifold) and go on checking for spark.
Now for spark - I'll quote labman (member of this forum)... "If it has spark plug wires, pull one off and hold the terminal near a ground while somebody cranks the engine over. If you don't get a spark, start checking the ignition system." So, since we do have spark plug wires, pull one off. Now there are two ways you can check for spark: with a spark plug or without. If you want to do it without a spark plug, do as labman said. I personally like the spark plug method better. Take one spark plug (known working one), plug it into the wire until you can feel it touched the metal inside the wire, hold the wire by it's top (what you used to pull on to pull the wire out of the spark plug hole in the valve cover) and make contact between the top of the spark plug and the chassis (any piece of body under the hood enough away from the fuel filter and fuel lines). Now have someone crank the car while you look for sparking on the spark plug. Do this process with all 4 spark plug wires. If you're getting a spark on each wire, then the only problem might be wrongly set timing. If you're not getting a spark, and ignition coil and igniter unit both test fine (read on for procedures how to check those), then either spark plug wires or distributor cap and rotor must be replaced (wires, cap and rotor are cheap things... you should replace them all if you're not sure when you last replaced them). If ALL fails, it might be possible that your internal sensors inside the distributor went bad. You should replace the whole distributor.
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Checking your spark plug wires:
Service Manual says that you disconnect each spark plug wire off and measure resistance between the 2 ends of the wire. Resistance should be less than 25000 ohms on each wire.
When taking wires off, it's best to do one at a time. If you take all off and forget where each one was connected to, and connect them back in wrong order, you will get sparks on wrong cylinders, and your car surely won't start. So, be safe and take off one wire at a time.