Dragon760

Hey there. I am having idle issues with a 1997 Honda Accord. It idles fine cold and once it warms up the idle gets rough then stalls. There is no CEL light. I've checked and changed the entire ignition system (spark plugs, wires, cool, cap rotor, distributer). I've cleaned the EGR ports and EGR valve (which were clogged). I've removed the the IACV and cleaned and reinstalled. (The screen was dirty). I disconnected the battery terminal to reset the computer and so it would relearn the idle. I'm not sure what else to check. Is it possible that the IACV is still bad regardless of cleaning? Is there a way to check if it's functioning properly? It's a pricy part so id hate to change it to find out this isn't the issue. I've tried unplugging the IACV and there is no change in the idle, all it does is throw a CEL. I haven't removed the TB and cleaned it but did spray some carb cleaner in as it runs. Any help or suggestions for my issue would be appreciated.

holmesnmanny

the idle should drop when u unplug the iacv ... unplug it and test it for ohms it should be around 8-12-15 ohms or so across the pins somewhere in that range... if thats ok check base idle by unplugging it and idle should be 500-600 somewhere in there ... if not i would take the tb off and clean it real good after getting a new tb gasket ... then check the base idle again .. if still bad could be a bad oxygen sensor

hondamark35

seen similar issues as a result of a 90% clogged catalytic converter. the "honeycomb" structure had actually started to melt down. it's a quick check once the car is up on ramps or jack stands (assuming all the fasteners aren't rusted beyond recognition ) take the upstream (engine side) flange of the converter loose and have a look inside.

holmesnmanny

if the cat is clogged wouldnt it act up on a cold start too ?

hondamark35

the times i've seen it, it would run fine until the temp aproached normal then start idling rough, trying to rev would make struggle and want to cut off. with no other changes, running with the cat off the car fixed everything.

i never really tried to completely understand the situation. once i found that the cat was no good and it ran fine with it off, i just swapped it out and let it ride. maybe the higher idle and rich mix durring cold start was enough to compensate for the reduced flow. it wasn't completely plugged, so there was some flow.

Dragon760

Holmesnmanny

As soon as I unplug the IACV the car dies(car is warm). When I plug it back in it's thrown a CEL code. Clear code and same issue persists. I tried putting the car under load (A/C) and while in park and at idle it stays idling. As soon as I take it for a drive after warming up it stalls when I slow down or stop while car is in drive or reverse. After I put it in park and up the RPM's for a minute or two the car levels out and idles at around 850 - 900 RPM. I tried to adjust the low idle but the car won't stay idling long enough to make the adjustment. I'll check the olms on the IACV.

Dragon760

I also forgot to mention that as the car struggles to idle I can hear a clicking noise coming from the area of the IACV.

holmesnmanny

has the idle adjust screw ever been tampered with ? when you unplug the iacv the car should idle at 600 rpms and rise back up to 750ish when uplug it back in. If you did mess with it u should adjust it back to 600 rpms with the iacv unplugged. Then plug it back in and see if it goes back up to 750ish. Do this after the car is completely warmed up.

Keep in mind the very first white line after 0 rpms is 500 then 600 then 700 ect

holmesnmanny

its probably just the injectors opening and closing thats a normal sound.

Dragon760

I've never touched the low idle adjustment. It was never an issue before and I've had this car for about 2.5 years. It's like one day the car start to have a rough idle. I checked the power going to the IACV and it's within the right ranges. I guess next step is to remove and clean TB and clean and adjust the FITV if it's loose. Would an improperly adjust distributor cause this issue? I did replace it and perhaps I got the ignition timing wrong.