Problem with 91 Honda Civic

When you say your car does not start, does it make any cranking sound? If not, the starter could be bad.

Assuming the starter is fine but the engine does not turn over, then you need to check to see what is missing: spark or fuel. There are two most common causes of no-starts with Hondas - the ignition module (inside the distributor) or the main relay. My father-in-law had a similar problem with his '89 Civic and I found the main relay is bad. It does not start when it is hot (or even just warmed up). I removed it and reworked the solder joints and it is fine now. The main relay is located under the dash to the left. I believe your model year uses the same type/brand. It is black and the maker is Matsuba (I think...). Just remove the mounting bolt and unplug it from the wire harness. It is easy to pop the relay open and resolder the everything on the board. To check it, if you turn the ignition on it should make a clicking sound and the car will start. If it does not make a clicking sound, the car will not start.

It makes a cranking sound, it is not getting fire. Someone told me that it could be the gas I am using. I use citgo 87. They told me to use Amoco or Exxon 89. I thank you very much for your help. The part you said I need, can I do it myself or I have to get a tech to do it?

I'm quite sure the problem is with the main relay but here is something you can do to double-check:
Buy a can of starter fluid. The next time the car would not start, use a Philips screw driver to remove four screws holding the throttle body cover (it's the black metallic cover on top of the engine). Spray some starter fluid into the throttle body and place the cover immediately (even with just two screws) and try to start again. It is best if you can have someone try to start it immediately after you sprayed the fluid. Don't forget to check the cover to make sure you have reinstalled all four screws back.

If it starts, the problem is definitely the main relay. It's clicking sound when you turn the ignition to the ON position indicates fuel has been delivered to the chamber for starting. All you need then is spark from the plugs for the engine to start.

It is quite easy to change the main relay. As I have mentioned in my earlier reply, you may need to just resolder the contacts on the relay's PCB. If you know how to do soldering, you should just do it yourself or ask someone you know to help you. The relay is under the dash on the left end mounted with a single bolt. Make sure you disconnect the negative battery cable before you do anything. Remove the bolt then disconnect the wiring harness. You can pry the plastic cover (black with Matsuba labeling) off with a flat screw driver. Resolder the board. This main relay is a common problem with your car. Installation is the reverse of removal.

By the way, you should also scan the car's computer for errors. If the problem is the main relay, you will get a code 16. The computer is under the carpeting on the passenger foot rest. There is a lamp (LED) on top that you can use to count the number of blinks. You will see it after you remove the carpet out of the way. You start counting after you turn the ignition to the ON position. Code 16 will have 16 successive blinks of the red LED. Code 16 means there is a problem with the fuel injector circuit. This circuit includes the main relay.

Thank you again, I am going to try that when I get off work (see if I can do it myself) I will let you know how everything went.

I have a 1990 Honda Civic. I have been having this odd intermittent starting problem for a year now. It ONLY has difficulty starting when the weather is hot. In the morning, everning/night, and during the fall/winter it starts like a champ, on the first crank every time. But during the hottest parts of the day it just won't. It sounds like it wants to but just doesn't. Now if I wait 30 minutes or so and try again it starts normally.

I have gotten a tune up, changed the fuel filter, air filter, flushed the radiator, and checked the battery but the problem persists in this very predictible way. I read from someone else's post that for many Hondas the main relay is the culprit so last weekend I bought a new main relay from the auto parts store. Much to my dismay, the starting problem persists.

What am I not thinking of? What else could pose such a specific problem--starting problems during the hottest part of the day only, reliably starts 30 minutes after first attempt, never a problem at night or during winter?

I see these Honda problems and nobody seems to be solving them. I don't know too much about Hondas, but maybe you need to apply standard no start procedures when it is hot and not starting.

Since you say it sounds like it is trying to start, I assume you mean it is cranking. Move on to checking for spark and fuel. Often a failing coil or ignition module will not produce spark or as good of spark when hot. Harder to do with the direct ignition, but pull the whole assembly off and hold one of the terminals near a ground when you crank. Spark, no spark? Pull an injector or the whole fuel rail and see if it sprays gas when you crank. Note, watch where you spray gas. Look carefully and see if start circuit has separate feeds for the gas or ignition from the run circuit.

If the engine is turning over, you have spark, and fuel, it should start. Find where something is stopping one of the 3 on a hot start, and replace it.

I may have to do that Labman. If it's the relay, as so many are convinced, it's going to manifest as a fuel delivery problem...I'll replace the fuel pump, but the problem will persist. I called the dealership yesterday and explained to them the problem and the guy immediately said, "It's the main relay." When I told him I already replaced it there was silence...then he said, "Bring it in and we'll run the codes."

Here's a finger in your pudding...it may be related or it may be a red herring. I hitherto figured it was a red herring and completely dismissed it. The power locks do not work during the day time. After sunset they function normally. This parallels my starting problems. Now, since I've already replaced the Main Relay could this be a POST-relay problem, I.e. The power locks and the relay share a common circuit or harness thereby persenting with a problem that seems for all the world to be a Main Relay problem? I sure would like to hear what you guys have to say before I dust off my credit card again and start yanking stuff out. :-/

The main relay and igniter are the most common cause of the 'no-start' problems with your Honda. Of the 4 problems I have actually seen, 3 are with the main relay and 1 is with the igniter. They are both heat-related.

If you followed labman's suggestion of checking for spark, it's almost certainly an igniter problem if you don't see a spark (when the car would not start, of course!). I heard there is now a better replacement for this igniter. It is easy to replace but you need to be sure because it is quite expensive.

My father-in-law's '89 Civic Wagovan started having this problem this Spring. When Summer came, it became worse. It starts fine cold but even after running it for 2-5 minutes, it will hesitate to start again... Until allowed to cool down. It had spark and I saw a Code 16 from the computer. I checked the main relay and it was failing intermittently. I reworked the solder on the PCB and it was fine again. I bought a new main relay but the old, reworked relay is still in the car with no problem.

I suggest you scan your computer for error codes. Code 16 would suggest a fault in the injector circuit - which includes the main relay. I forgot the code for a failing igniter - you can find it from a manual.

By the way, what brand main relay did you buy?