Ok so my civic randomly wont turn on. It will drive just fine and later when i try to turn it on it wont start. After a couple of tries it turns on. Also sometimes when it comes on the revs are at about 2k and stay that way until i drive for a few minutes. Can anyone point me in the right direction?? Please and thanks

 

Usually an idle problem when timing is set correctly is either the Idle Air Control Valve (IACV) or the Fast Idle Thermo Valve.

If memory serves me well, the IACV is calibrated at the factory so is a no no to adjust. I believe you might be able to clean them sort of, but just buying a new one is probably your best option.

I've never really looked into the Fast Idle Thermo Valve. Usually I see people having idle problems end up fixing it with the IACV, but the Fast Idle can also be a culprit.

Good luck.

 

@TomCat39 thanks for the input and info I will check both those valves and I will post up as soon as the problem is resolved

 

Oh, just noticed the year of the car on your profile, if this is the car it may not have the fast idle thermo valve. I read the thermo valve is 92-95. I'm no pro and learning right along with a lot of folks here.

As for the no start.. Sounds similiar to the my 93 civic dx automatic. It usually has a pause when I turn the key and then it cranks about 1-2 seconds later. Not really sure what it might be. One thing I read is maybe a Neutral Safety Switch which is found under the center console on the auto shifter. I really don't know what you have. If it's a manual, the switch is on the clutch pedal and may need adjustment or replacement if some rubber piece in it fell out.

To be honest, your no start issue is a bit beyond me and is something I'm just beginning to look into myself.

 

randomly not start and won't start after shut it down.

This sound to main relay!! did you hear the pump priming when not want to start.

 

@TomCat39 its an automatic. I know what you mean I am also confused by this

 

@carlos8 yea i heard the pump and it even smelled a bit like gas after a couple of attempts to start the car. I will check out the main relay could it also be my ecu?? I changed my exhaust manifold and the o2 sensors but my CEL is on and when the car got scanned it said that the parts I changed werent registered on the ecu. Once again thanks for the info

 

Remove the back up fuse to Reset the ECU, To see if clear the codes.

OK, If your pump is priming then check for spark . When the car do the fail again put a spark plug in one wire and have a friend crank the car and check if you have spark, if not this can be a bad ICM(ignigtor) knowing to fail but with the spark delivery instead than fuel.

 

@carlos8 thanks for the tips man I will do what you said asap :D

 

Ok soi have changrd main relay, ignition coil, cap and rotor and still the problem persists. The battery and distributor are fine. Im assuming the starter is fine as well buy will double check. Any suggestions??

 

Check all your grounds. Now would be a good time to remove all your ground wires, and sand them down with some 80 grit sandpaper. When I did it I also replaced all the 10 mm bolts with new ones from autozone. Obviously, the negative battery cable is the most important ground, so make sure to hit that. And not just the ends of the ground wires, but the chassis that they sit on. Get it all roughed up. then sand the battery terminals down, blow away any dust, and put it all back together.

 

Thanks man ill do that asap.

 

@crazyhouse2011 this morning i checked the negative battery ground and shows signs of major wear. I remember that when i first checked the battery a few months back a penny had been jammed in between the the ground connector and the battery terminal. I removed it and after that is when i started having this issue. Maybe the previous owner didnt wanna put in work and added a copper penny to improve conductivity.

 

Ok so i have fixed the starting issue. Now im looking into my rough/high idle.vi have already changed iacv once but i might do it again and see if that solves the problem. I also reset the ecu and the same codes pop up.