Hi folks,

I've been having this rough idle problem with my wifes 2000 SE 4 cylinder VTEC 130 K for a while.

Just before we went on a 3500 km road trip last week. I had an oil change, complete tune up, wires plugs rotor and cap along with all the fluids changed. The car ran fine except for the rough idle when warm and intermittently hunting when idleing. Another odd thing is that when I turn the AC on it affects the idle, causing it to run even rougher.

I don't have any check engine lights on so I can't really use that as a guide, everywhere I look it seems to me that it points to a lazy 02 sensor, but I can remember reading about someone who changed them and had no improvement, since the idle issue was caused by a totally different sensor that even the scan tool didn't pick up as faulty.


Does anybody know what sensor other than the 02 sensors that may be causing this problem, since the 02 sensors are expensive and if they don't need replacing I don't want to waste my money only to find out that it wasn't the cause.

Thanks in advance
F.O.G.

 

What's your idle RPM? Maybe you need to go through the procedure of setting your BASE idle & re-setting the ECU so it can re-learn it's idle control.

Automatic tranny? If so, the rear engine mount is vacuum-operated. That's supposed to get softer when idling in gear. How does it behave idling in D or R? As opposed to idling in N or P?

There's a vacuum hose going down to the engine mount (near center, low, back at or under the firewall). There's a solenoid valve in that vacuum hose, unplug the wires. That SHOULD make a big difference in vibration when idling in R or D.

 

2 things you might try, Clean out the throttle plate area with Berrymans B12 carb cleaner and your wifes toothbrush. ;-].
Also remove the IACV and blast it out with the carb cleaner, the screen can get clogged with oily vapors and crud.

 

Thanks guys, I'll look into those suggestions. But I still wonder why the rough idle increases when the A/C is turned on?

 

good info again

 

Honda's idle control system seems to like the IAC valve to operate in a specific part of it's control range. But if the BASE idle is a little low, the IACV can open up a bit to compensate. But then it runs out of range to compensate for the AC compressor.

Small adjustments to the idle air needle valve can be made without any immediate, obvious consequences. But they influence how well the system handles OTHER stuff like the load of the AC or of high electrical loads.

 

I've had a very similar problem... I took the car in for a smog check, and it started to stumble and stall at idle.

I've reset all the odbc codes, and it improved for a short time, then came back.

Checked the hoses, filters, wires with nothing unusual.

I let the engine stumble for awhile, then heard a 'click' like a relay or solenoid... Afterwards it ran smoothly.

Any ideas?

 

His car is a 2000 4-cyl. What's yours?