My recently purchased 1998 Civic LX 5-speed suddenly loses idle at a complete stop. Everything runs fine otherwise except in neutral at a light ect. It will stop completely unless I keep the RPM's up with the gas pedal. Is there a stepper motor or idle adjustment? Also I am new to Honda's, what is a good repair manual to help a shadetree mechanic work on their Honda (besides Haynes)? Thanks in advance for all opinions ect.

 

How does it idle otherwise? Cold idle okay when you first start it up?

If this is your ONLY symptom (and this is gonna sound crazy), have your alternator checked by someone who knows Honda charging systems. If the alternator "FR" signal isn't working, the ECU will (1) turn off the alternator and (2) make faulty assumptions in setting the idle speed. The classic symptom of a bad FR signal is .. car stalls at stoplights.

Here's a Motor Magazine article that describes the Honda charging system.

Re: repair manual, why not go with the genuine Honda Service Manual? You can get a printed version from Helm, Inc. or a CD version on eBay.

 

sounds like a bad EGR Valve. Haynes manuals suck, try to get a Helms or Chiltons manual.
EGR Valves run $100-150 from a dealer with a new gasket and on a Civic it would be EASY to replace. I wouldn't even bother buying a shop manual. When you get the part it will make sense.

brad

 

Brad,
If the EGR valve is bad, wouldn't that cause a flaky idle all the time? Why just when he decelerates to a stop?

EGR valve is easy to check, though. Just take the hose that goes to it, apply vacuum to the hose (suck on it!) and the engine should stall. If it does, the EGR valve is okay. If it doesn't, the EGR valve is probably clogged.

But if the valve's clogged, that means there's no EGR action -- ever. Since there shouldn't be any EGR action at idle anyway, why would that make it stall at idle? There shouldn't be any EGR at idle to begin with.

Hmmm. Maybe the EGR control circuits are messed up, putting vacuum on that line at idle, when they shouldn't. But, again... why only when decelerating?

Can you help me here? What am I missing?

 

Here's an update. Yesterday morning the Civic stalled many times in heavy traffic as it slowed with the car in neutral. Otherwise when the gas was applied it was fine. Then later in the evening when the car had been sitting off for about an hour I got in and started it up. It idled fine at first but slowly went down to around 1000 RPM's or less. If I get an OBD II check will that be able to tell me anything about the EGR? There are no check engine lights on right now. Thank you for the responses.

 

yes, and OBDII check will tell you if there is something wrong with the EGR. What happens is that the EGR Valve gets stuck in the open position, usually once the car is fully warmed up...and then stays open when the engine returns to idle, and stalls the motor. It can also make acceleration lag when it gets stuck too.
Other causes for this problem could be: fuel filter, ignition system

I'd put my money on the EGR...

brad

 

Yes it's more apparent when it's warmed up. I have taken off from a cold start and it idles fine until about 3-5 minutes of driving. I will get the OBD II check today. Thanks all!

 

Aneurysm,Yeah... that would cause those symptoms. I usually think of clogged ports when I think of Honda EGR problems. But you're right! That could be the problem.

Thanks for the explanation.

BTW, is there any particular "age" or "mileage" when the valves begin to get stuck open? (Clogging usually occurs on older, high-mileage valves. Same here?)

 

from my experience, EGR valves usually go bad when the motor gets older is when it happens. Maybe 100k-150k miles. I'm sure there are many factors that could change that estimate though. Cleaning the valve with carb-cleaner is a temporary fix. I've tried that a few times in the past and it usually only helps anywhere from a few hours to a couple of days at best.

I would recommend www.slhondaparts.com if you need a cheap source for Honda OE parts. They also have all schematics online for viewing. Its a SUPER easy install though. I can change it on my Prelude in about 3 minutes with a 1/4" socket wrench, extension, and 12MM socket. Far as I know, ALL Honda EGR valves come with the new gasket too.

Good luck with it!

brad

 

I had Autozone check it with their OBD-II scanner today and no codes showed up. Everything passed. All today it idled fine at about 500 RPM's in stopped traffic and never stalled once. However I have an uneasy feeling it will come back though.