Hey everybody. I found my way to the forum because I'm getting stuck trying to get my fiance's 92 civic LX running. Please bear with the long post, I'm really desperate.

It simply stopped shortly after startup one time, and now it will crank strong, but makes no attempt to fire up.

I used a spark tester on the plug wires, and I'm not finding any spark at all. For kicks I also listened for the fuel pump, and found it wasn't running either. Uncovering the fuel pump revealed that the connector on top was melted, so i replaced it with one from the junkyard. Then I was not seeing voltage at the connector when the ignition was on. I unplugged the fuel injector pump relay under the driver side dash, and jumpered the 5 and 7 terminals in the connector together (per the haynes manual) which made 12v appear at the pump connector. The book says that would make the pump relay bad, but i bench tested it (per the book), and it works ok.

Next I checked ALL fuses under the dash, and under the hood, and no problems there either!

What else could be causing this problem? Bad ECU? I read something about an Electronic Load Detector (ELD) but I can't find it to test it!

Please give me some more ideas of what to check! And thank you for reading!

 

Does the CEL stay ON when the ignition key is turned to ON (II)?

Check the critical ground wire connected to the thermostat housing. Remove it and clean it thoroughly with some steel wool so that it is making good metal-to-metal contact.

Also double check all ECU fuses under the dash and hood.

Next check whether the wire between the ECU and MAP sensor has 5-volts when the ignition key is turned to ON (II).

 

check your main relay. it's an old enough civic that it was a common problem. resolder the connections as they tended to crack due to the heat and cooling of the seasons.

 

Thanks for the replies!

The CEL does stay on with the ignition on (engine not running)... is that good or bad?

Does a lack of 5V at the MAP sensor indicate a dead ECU?

Is the main relay also known as the Fuel Injector Pump relay? The one above the driver side front kick panel? With 7 prongs? Or is it something else?

 

The CEL indicates a problem with a sensor. Retrieve the code as detailed at the link in my signature as it may help troubleshoot the problem.

Typically yes.

Yes; however, a bad main relay would only cause loss of fuel not loss of both fuel and spark.

 

Go ahead and resolder the main relay because though it may not be the problem now, it will later if you don't.

Also check that you're getting power to the big black/yellow wire on the distributor with the key on.

If you don't get sensor power, check for the sensor circuit shorted to ground, also check that the ECU itself is receiving power before condemning the ECU.

 

I think it's best to start by considering a single explanation for the no-fuel and no-spark problem, although as mk mentions, it's also possible that there are two separate problems.

 

Ok, I just got back from the car (it's still in the spot it died). The 2 powered wires going to the MAP sensor only read 0.35V. The book also said to check them for 5V, but it doesn't say what to do if it's not there!

I had tried to pull codes from the CEL using the same method you suggested as one of my 1st troubleshooting steps, but the CEL would just stay on solid with the jumper in. No blinking *shrug*.

How do I check if the ECU is getting power? The book has no diagnostic tips for the ECU, so I'm not sure what else to test. I'll have to try to test the MAP sensor circuit for a short tomorrow.

There doesn't seem to be a short between the fuel pump wires, or between them and ground. I think that the connector may have been loose or dirty, and the bad connection created the heat to melt it.

What is there to solder on the main relay? Could you explain that process a little more? The relay I'm looking at has a bunch of broad pins in a connector, and it snaps into a connector on the end of a wire harness. The wires in the harness connector seem secure.

I think this is looking more and more like the ECU. Any other diagnostics for it? Or should I be looking for a problem that may have killed it so i dont kill a new one too?

 

You pull it apart. The relay components are on the red? brown? plastic part with the pins. The grey? part comes off and is just a cover for what is inside.

http://www.marklamond.co.uk/tech-hon...main-relay.htm

Read that if you want to repair your main relay. Otherwise, let's see what RonJ has to say about this new information.

 

I guess I'm ordering a new ECU unless anyone has any other ideas...?

Does anybody know a good place to buy an ECU? Or maybe what I should be looking for in a compatible one in the junkyard?