Car not starting...possibly an ECU issue?

**zel05** · 19-11-2009 05:57 PM

Hey,

Just wondering if I could get some pointers as to determining why my car wont start.

Just quickly, the car is a eg civic with b18cr conversion.

To give you an idea of what has happened:

Got home with the car at 6pm, go to leave at 8pm and the car wouldnt start. I'll describe the key positions as 1 and 2. On 2, the usual dash lights would come on, slightly faint, but they would turn on. One thing I did notice was that the interior light would not be on at this point. I turn it back to 1, and the interior light would come back on. I then go back to 2, and the fuel pump would turn on and everything would seem fine. Go to start the motor...and nothing.

This afternoon I had another try. I reset the ecu, and the dash lights would come on with full brightness, unlike previously. The radio would work, and at full strength, this gave me the idea that it wasnt battery related. I then roll started it down a hill, and it fired and started. I drove around for about 30-45 mins. Turned the car off, and then tried to start again, and nothing like before.

Any suggestions and what I should try next?

Thanks

**02gzm** · 20-11-2009 08:19 AM

I would have said your starter is gone but since the electrics are playing up it sounds like a short in your starter circuit. If you've got a multimeter check the wire from the ignition switch to the main relay (pin 4) and from the main relay (pin 8) to the ecu (pin A23 or A24). The fact that it runs fine after it's roll started means the wiring from the main relay to the ecu should be fine though.

This picture will help explain what I mean. Check the circuit highlighted in blue.

If you aren't to savvy with a multimeter another way to test the starter circuit is to hold the main relay when you turn the ignition switch to 'start'. You should feel the relay click when it engages the fuel pump circuit like in the picture above.

If you can't find the problem yourself, roll start it, take it to an auto electrician and explain the situation.

**ECU-MAN** · 21-11-2009 12:44 PM

dead battery or poor battery terminal connections

**zel05** · 21-11-2009 07:52 PM

Thanks 02GZM and ECU MAN.

It was actually a flat battery. Obviously my knowledge of batteries wasnt as savvy as I assumed. Next door neighbour showed me that I only had about 4.# volts when trying to turn the engine over. Replaced the battery, good as new.

Thanks again/