Rep Power: 0

I have a 98 Civic DX with 145,000 miles on it. Been running fine, no problems at all. Last Friday, I decided to do some 'preventive maintenance', and replaced following-

Distributor cap (O'reilly recommended brand for my car)
Rotor (O'reilly recommended brand for my car)
Spark plug wires (NGK)
Spark plugs (NGK)
Air filter
(all done myself)

Oil & filter change
(Done by garage)

Everything ran great for five days. On Thursday, I noticed a 'rotational grinding' sound coming from the engine compartment. Almost sounded like a water pump or alternator bearings going bad. (water pump was replaced with timing belt at 100K). Noise very noticeable at initial startup, and turn off. Car ran fine otherwise.

Was going to bring it in to the shop the next day, but as suddenly as it started, the noise is gone on Friday morning.

Five minutes after starting it post-noise, the car stalls at low RPM. Engine light comes on. Car starts right back up, no hesitation at all, but seems to have a low idle, and will stall if I take off the gas consistently. Car seems to run FINE otherwise. No noises, no rough idle, no other symptoms, but stalls consistently at low RPM.

While I am mechanically inclined, I won't claim to be an 'expert' at car repair/maintenance. My first inclination is that I did something wrong while replacing the distributor, etc, although I can't imagine what especially since it ran great for five days. I could be completely coincidental, but it seems odd that it happened so suddenly after maintenance.

I'm going to pull off the distributor/rotor and check connections, etc, today.

Any ideas?

 
Rep Power: 812

what does the engine light say? its prolly something with the distributor cap. either you forgot to screw it in or its loose.

 
Rep Power: 0

Well, I pulled off the distributor cap, and checked the spark plug wire connections. It doesn't seem to stall as often, but the idle still seems very low, and like it's 'trying' to stall.

I also notice that it stalls if I rev the engine (in neutral). When it returns to idle, it's almost like it drops too low and stalls out.

When I start it, without reving, it's fine.

 
Rep Power: 267

Are the wires in the proper sequence on the distrubutor cap? You said a light came on. What is the code?

Cap should be:

1: Left
2: Bottom
3: Top
4: Right

When looking at the engine from the front, sparks plugs are numbered 4,3,2,1.

 
Rep Power: 812

i think its time to clean out the whole intake system, including throttle body and all the sensors around it like idle valve. thats the reason its trying to stall, cant maintain idle when you let go of the gas. get some carb spray and clean all those lil things you can unbolt.

 
Rep Power: 267

If you decide to do this, don't touch your idle screw. It was pre-set at the factory. Check your idle RPM (engine at normal operating temp) with a meter before you touch anything. If it's out of spec, clean throttle body and particularly the IAC valve using break or carb cleaner. This should correct the RPM.

But, you should probably do that last since it's a hastle, and you may not need it.

 
Rep Power: 0

I was very careful about not mis-connecting the wires, set the new and old caps side by side when I plugged the new wires into the new cap, but I'll double check.

Is there a way to check the engine code myself? Or do I need to bring it in? Also, how do I reset the engine light to verify it's still coming back? I disconnected the battery for about 30 minutes, that was obviously a futile attempt.

Thanks for the suggestions guys. Also, thanks for the advice about not adjusting the idle screw, that's something I actually considered.

I'll try cleaning the intake system as suggested.

 
Rep Power: 0

delete

 
Rep Power: 267

Take it to autozone or whatever, and have them hook up a reader. If you ask them to delete the code for you, it's against their policy so tell him that you'll delete it. Make sure you delete it to see if the code comes back.

Oh and you can rent the reader for free from there too in case you can't get the car there.

 
Rep Power: 267

You didn't grease the coils did you? I don't remember if they come with grease in there already, or if grease isn't supposed to be there at all.

 
Rep Power: 0

Grease what coils? Obviously the answer is no, I applied to grease.

 
Rep Power: 812

you should put a bit of dielectric grease on the boots and the metal contacts, helps keep corrosion out.

 
Rep Power: 267

Okay, I couldn't remember if they were supposed to be grease free or not.

 
Rep Power: 0

No, I did not. Was I supposed to? What's the final consensus?

I did remove the throttle body and air control valve. They was dirty as hell, and I cleaned the crap out of both with carb cleaner, scotchbright, and a rag. Ran fine afterward, but I've yet to drive and warm it up.

How common is it for the ACV to go bad? Seems like a possibility.

Also, is it necessary to 'relearn' the idle with a 6th generation civic? Probably going to try it anyway, can't see the harm.

 
Rep Power: 267

Remove the negative cable, press brakes to remove all current, then re-attach. Then let the car idle for a few minutes. But the car is always learning so...

 
Rep Power: 267

NGK wires come pre-lubed.

 
Rep Power: 812

yeah idle learn is a good idea. just let it idle for 10 mins after removing battery without pressing gas or using accessories. its better to warm up the car first before disconnecting battery.

 
Rep Power: 0

Cleaning out the throttle body and idle valve definitely fixed the idle problem, hasn't stalled once since I followed your advice...Thanks so much Gearbox!

Now it seems the 'grinding' noise has come back. I assumed they were related, apparently not. The noise gets louder when the accelerator is pressed, quieter when released.

I know it's damn near impossible to diagnose a 'noise' without hearing it in person, but any suggestions on how I might narrow it down?

 
Rep Power: 812

usually grinding is clutch related if you have manual trans.

 
Rep Power: 267

I still don't see a code reading. And it's not like you installed a new transmission here, rather you only replaced minor parts. Shouldn't be a problem and easy to fix if it is. The car was working before, now it's not. Should be simple.

 
Rep Power: 0

Yes, manual transmission, but clutch was replaced about 20K ago. I had a bearing in the transmission making noise, and they replaced the clutch along with replacing the bearing (also had a cracked exhaust manifold replaced, although irrelevant).

Going to stop and have the code read today.

 
Rep Power: 0

Okay, so once again my noise is gone. Would a bad bearing come and go like that?? I doubt it. Nothing like troubleshooting an intermittent NOISE problem. I'm about to solve the problem by just turning up the radio...

It's running great after Gearbox's suggestion to clean the throttle body (MUCH thanks again Gearbox!).

 
Rep Power: 812

no prob. noises are tricky, if it goes and comes, the best thing is wait until it gets worse. othjerwise its hard to locate the problem.

 
Rep Power: 267

I've got that problem, or something similar. I replaced that bearing(s) when I did a trany rebuild and it made no difference. I even staked the countershaft bearing. Do you get the sound with the clutch up? It's either your counter-shaft or mainshaft bearing if so.

But it might not be the bearings at all. It could be the slave cylinder ball where it manipulates the release bearing fork. Maybe it's rattling against the fork. I have to check myself...

 
Rep Power: 0

When the noise is present (again, it's intermittent), I get it constantly. In gear, while driving, in neutral, clutch in, clutch out. As far as I can tell, it's coming from the belt side of the engine, and not the transmission side, although I know that noises can be misleading. Maybe that's just wishful thinking that it's NOT related to the transmission!

Stopped and got the code read today. P0135. O2 sensor heater circuit bank 1 sensor 1.

Going to check the wiring and connections at the O2 sensor today. I had the manifold replaced, but I'm guessing they didn't replace the sensor. @ 145K it's probably overdue anyway.

I really appreciate everyone's replies. Again, I'm mechanically inclined (I've worked on copiers, printers, and other electro-mechanical devices for well over a decade) but somewhat inexperienced with auto repair other than the basics, and certainly little troubleshooting skills. I stumbled across this forum, and have learned a TON. Everyone on here seems very knowledgeable, supportive, and in general a great group of people! A great find for the wanna-be DIY'er!

 
Rep Power: 0

Received and replaced the O2 sensor today. Engine light is gone...I was surprised I didn't need to have it reset, although I did disconnect the negative battery cable for 15 minutes, then let it idle for 15 minutes to relearn the idle.

Final verdict is that everything is running great, and the idle sounds good. Thanks again for everyone's help!

 
Rep Power: 812

disconnecting the battery resets the ecu.

 
Rep Power: 0

Cool.

Much appreciation and respect to you gearbox...been reading a lot of random posts on this forum, and I constantly see your responses with always informative and helpful advice. As a 'wanna-be' mechanic', it's very reassuring to know there is someone with your level of competence willing to offer support and assistance..and without making the questioner sound like an idiot for asking. I just wanted to say thank you again!

 
Rep Power: 812

no problem, im not a real mech either, just playing around for fun.