literallarry

1998 Civic LX- the engine has been randomly dying while driving for some time now. It happens at all speeds and is very unpredictable. When it does die, it is only the engine. All the power remains on and check engine light comes on. It usually takes about 10 minutes of trying to restart and the engine will turn back on. The engine will only turn back on once the check engine light goes off, again which takes about 10 minutes to happen. I recently was able to hook up an obd2 reader to the car when it happen to die. The reader would continuously say that it could not connect to the car, even though the check engine light was on and everything was hooked up correctly.Pretty sure it's not the brand new obd2 reader.

On a few rare times it died on the freeway but then fired back on quickly when my foot remained pressed on the gas pedal.

I've been given several suggestions:
ICM
Ignition coil
Ignition switch
Fuel pump
Fuel pump relay
Distributor..etc
Main relay

Dont know where to start. Any help would be appreciated.




P.S alternator and battery were tested and proven to be good.

Thanks

ezone

Does the code reader work on this car while it DOES RUN right?

literallarry

Yes it does. This obd2 reader gave live info with the car running. Of course no codes because the check engine light was off.

ezone

If the PCM quits communicating at the same time as the engine starts acting bad, then you have a PCM problem. Either the unit itself is heading south, or it is losing power or ground and shutting down.

I would monitor the powers and grounds at the PCM connectors just to rule out the possibility of a wiring issue (see what they do while the car is acting up), and condemn the PCM if the powers and grounds are perfect.

I can't just tell you to put a PCM in it, but if you have a good one available to test with that would speed things up a lot.

literallarry

Awesome thanks for the response. I will monitor that. I read in another forum that a guy describing my exact same problems with his 98 civic replaced his main relay and this solved his problem. I changed mine just about an hour ago. My car starts up and it drove fine around the block. I'll need several days with no dying to know for sure if it worked. I will monitor and report back.

ezone

I was a bit confused with the check engine light description..... The PCM controls the CEL, so if the light does not come on then the main relay is one of the first things to check....(That should be covered in testing as one of the power and ground checks if you could catch it acting up.)
Whenever I get a main relay that is bad, it has always been just a plain no-start with either the fuel pump inop or the CEL doesn't come on. Never been able to witness one dying on the road because of the main relay....but then again I usually don't get to see the cars until they are really completely dead and towed in to the shop.