Serious Rough Idle and stalling on 89 Civic

[mmdir2002]

89 civic with 200K miles on it. I'm having a very serious rough idle and stalling problem lately for past 2 weeks. Previously I did had a little rough idle problme during warm-up and I ignored it as the car warmed up the rough idle is gone. Now in past 2 weeks, it got worse. I thought it has to do with cold weather. During warm-up the rough idle is so bad that the RPM needle is moving up and down crazy and I've never had this terrible idle problem before. Not only that, the car is stalling when I stop at red signal. Never had that before although the car has never shut off. One thing I do know is that the car does not stall when I push the gas. Why is that stalling at idle? Is fuel filter is about to go? Shall I replace rotor or igntion coil? O2 sensor? PCV valve? Other?

 

[etienne]

Possibly a worn out distributer shaft. I had a 92 Civic that idle rough and stalled. Took it in and the guy diagnosed it to worn out distributer shaft. I had the distributer replaced and the problem went away.

A worn distributer shaft could cause the rough idle and stalling as the timing is not steady and varies all over the place.

A way to check for distributer shaft, is open the distributer cap, and see if you can shake the shaft, ie does it rattle? Also connect a timing light and see if the timing is steady.

 

[Elle (2)]

Here's what I would do, in order, based on my experience and some reading here:

Properly purge the cooling system of air. Use the manual's directions. www.autozone.com has a free online repair guide for your car. Remember, it will likely take at least 40 minutes for the fan to come on twice. The coolant has to get as hot as possible, so as much air as possible is released during the procedure. The cooling system cools not only the engine but certain engine sensors which will affect RPM. In particular, the cooling lines to the EAC valve are a high spot where air can accumulate. This valve directly affects the idle.

Ensure the ignition wires and plugs are genuine Honda or the ones Honda specifically recommends. NGK plugs seem to be the preferred ones. Prior to replacing the ignition wires, run the car and with an air mist sprayer, spray them down thoroughly with water. If the idle changes, definitely replace them. See www.tegger.com/hondafaq 's section on running problems for elaboration on this.

I am doubtful the air and fuel filters are the problem, but I would still replace them, and at least clean and check the PCV valve (with WD-40 or PB Blaster) as well. If it's the original PCV valve, I would consider replacing it with a new, genuine Honda one. Replacing these last three things (air filter, fuel filter, PCV valve) will minimize interference with your efforts. Besides, they are all routine maintenance items that have to be changed every so often, anyway. Total cost should be under $75.

The distributor cap and rotor should be genunine Honda and not too old, also.

Check and adjust as necessary the idle speed. See the manual for how to do this. Check and adjust as necessary the ignition timing.

I would not suspect the oxygen sensor or coil at this point. An old O2 sensor can be a problem /after/ warmup. An old ignition coil also tends not to be a problem until after warmup, as well.

On the other hand, replacing your O2 sensor pre-emptively is not a bad idea at this point. Aged O2 sensors do affect performance in general. The place from whom I bought my 91 Civic's new, genuine Honda oxygen sensor had very low prices for them. I don't know if they ship outside the U.S., but for price comparison purposes, see them at https://www.automedicsupply.com/ . A sensor for your car from these folks should be under $50.

Updates are welcome, to help someone else in the future.

 

[mmdir2002]

Thanks for input but I'm looking for a specific part that is direct causing the problem.

 

[Elle (2)]

Thanks for input but I'm looking for a specific part that is direct causing the problem.

Do tell.

Ever notice how manuals have "troubleshooting procedures"? For example, a certain troubleshooting procedure will list a number of symptoms, and the steps have the technician (or amateur do-it-yourselfer) investigating a number of possible causes.

But please give this tip of yours to all local mechanics and physicians. I too am tired of them not being able to diagnose a problem, and then fix it, the first time I present it. They mess around trying different things, and after an hour, some still haven't diagnosed the problem. Or worse, they'll insist (in true macho style) they have fixed the problem, and I'll be back within two weeks, with the problem still present.

Anyway, I don't want to push you around. The School of Hard Knocks is superior to any old person sharing their experience. ;-)

 

[mmdir2002]

Yeah I unassembled rotor and cap and cleaned the metal part bit of decomposed area with sand paper and I replaced PCV valve. The rough idle seemed to bit disappered. I will try to replace fuel filter next and see what happens.

 

[etienne]

Did you shake the distributor shaft to see if it was loose? Did you connect a timing light to see if the timing was steady? Also do you hear ticking noise from engine? This is usually a sign that the valves need adjusting. All of these troubleshooting steps do not cost any money and do not require replacement of parts.

 

[Elle (2)]

do you
hear ticking noise from engine? This is usually a sign that the valves need adjusting.

If the ticking goes away after warmup, perhaps a check is appropriate, but an adjustment may not be. The valve lash may simply be set at the high end of the spec, which is less risky than it being at the low end.