Hey guys wondering if anyone can help me out with this. I'm having problems with the idle on my Civic. Earlier last week my car would idle really low roughly 500 rpm and bog like it was going to shut down. The it got to the point where my car would shut down when making really sharp turns (i.e pulling into a parking spot). I called my buddies down and we ended up finding a disconnected cruise control hose hooked it back up and the turning problem seemed to go away.

Next day going to work my car would shut down when ever i would slowdown to come to a stop or make a turn. Managed to get the car home and called my buddies back down. We went through all the cables and connections and everything was in place. It came down to the ignition coil being bad that was causing the stalling. We got it swapped out with a new one and reset the idle and ECU and checked the timing.

While the car no longer stalls. I still get the occasional fluctuating idle and it still drops as low to 500 on occasion and will feel rough than bounce back up to 800 or so. I noticed it occurs the most when the engine is warm and when the day at its warmest.

We noticed there's a coolant leak at the thermostat housing. Is this possibly whats causing my idle to not be consistent?

97 Civic EX 5spd D16y8
AEM Cold Air
DC Headers
Recent work includes cap, rotor, spark plugs, wires, head gasket

 

Clean the IACV.

 

Already done, problem remains.

 

check iavc & map sensor...

 

I'd fix that coolant leak not to thread jack but I've had the same problem with my b16 swap its been a year and it still has a bouncing idle it sucks

 

make sure the coolant system has no air bubbles in it and bleed properly. then check for any vacuum leaks or try to turn in your idle air screw on the top of the t/b with a flat screw driver.( do this last as its only to be used to fine tune the idle)

 

How do I go about checking the map sensor?

 

bump

 

Ok so an update. I fixed the coolant leak and bled the system running the car with the cap off till the fan came on twice. The car seems to be idling better but still getting the occasional drop to 500 and then it bounces back up to 800. I also threw a p1831 code. I cleared the code and took another test drive the light didn't come back. Any other ideas bout the idle?

 

Our Civics don't have a code P1831.

Have you tried adjusting the idle speed as detailed in the service manual (see FAQs sticky)?

 

My idle bounced from 1000-2000 after I cleaned my IACV because my gasket had warped and no-longer sealed (the IACV gasket.) I replaced this gasket and my idle has been great ever since.

I've also heard that a bad PCV valve can cause idle hunting, look into that as well.

 

You may also want to check your intake manifold gasket (between the intake manifold and head). Some times an air leak there will cause a erratic idle...

 

Might have to do this, cuz my buddies set it with the IACV still connected then reset by disconnecting the battery.

I'm gonna order an IACV gasket and see if that helps. The intake and exhaust gaskets were just replaced so I might need to double check the tightening on the bolts. The cars running without dying, but im still getting what feels like sputtering when the cars idling at 700 and I still got the occasional drop to 500 when I went driving on my lunch break.

 

I haven't had an opportunity to readjust my idle, but now my car is dropping back to 500 like before and sputtering at idle. Is my IACV going bad or maybe my distributor?

 

If your ECU did not throw P1831, then what was the actual code?

 

I cleared the code already and it never came back. Is there any way to retrieve it when the ecu has been cleared?

 

No

I was just asking as the actual code may have been an important clue.

 

Bummer, any idea where I can go from here? So far I've changed my spark plugs, wires, cap, rotor, ignition coil. The IACV and throttle body were cleaned out when my head gasket was changed. My fuel pump primes, but I haven't checked the fuel filter yet. We did notice that when we pulled the old ignition coil it was hot to the point where it was difficult to hold. Maybe a clue into something?

 

My wife's car is doing the same thing; does yours only occur when the a/c is on, or is that not a factor?

 

Not a factor idles low either way

 

5-speed or auto?

 

5 speed

 

You'll find this in the FAQs sticky:

 

Will get to this asap

 

I reset my idle set ended up being around 800 was tough to set going by the dash tach. The car seems to be running better it feels like there is small sputtering though. I'll take it for another drive tomorrow when it's warmer.