Rough Idle/Vibration with/without A/C on

[DaChoZn1]

I did a search before posting and tried everything that was suggested.

I have a 96 Accord LX coupe, auto with 256,XXX miles on the odometer. I've replaced all motor mounts and tranny mount, cleaned the EGR, cleaned the injectors, cleaned the IACV, slightly adjusted the idle. Although it has somewhat improved, I still have a lot of vibration when I'm at a stoplight or in reverse. I gave it a complete tune up about 6months ago. The car runs like a champ at cruising/highway speeds. It just vibrates like hell when I come to a stop. It's really bad when I have the A/C on.

I'd appreciate any suggestions you guys may have. Thank you in advance.

[213374U]

What RPM's does it idle at? Sounds like you just need to make an adjustment. Should idle between 900-1200 when warm

[DaChoZn1]

I'd say about 700-800 Rpm's.

I also should note that I replaced my OEM mounts with Ebay mounts. I'm beginning to wonder if that was my 1st mistake.

[nwf_snake]

900-1200 when warm???

Mine idles at the little idle mark on the tack, maybe 700rpm...

[213374U]

When it's idling rough, bring the RPM's up to 900-1200 and see if it goes away. Almost positive this is your problem though.

EDIT: Just read your post about eBay mounts. Are they OEM, Anchor, or something else?

[DaChoZn1]

I'll give it a try. 900-1200 sounds kind of high? I believe my mechanics manual says that it should be about 650-750 If I remember correctly. At this point I'll try anything.

I'm not sure what brand if any my mounts are. I bought it from a "POWER SELLER" company on e-bay. They're supposed to be direct OEM replacements but not geniune Honda. I paid about $100 for all 3 motor mounts and the tranny mount. So the quality can't be that great. It was a lot of work replacing all of them. I sure hope I'm not going to have to do it all over again because I bought cheap replacements.

[213374U]

If they are OEM replacements they are more than likely made by Anchor. Decent mounts

[billyrusa]

Idles 700-800 RPM should be correct. The manual says 700 +/- 50. If the vibration vanishes when idles is over 1000 RPM, it is a possible rear mount system problem. Check the vacuum and voltages on the Rear Engine Mount Control Solenoid. If they are correct, check the rear engine mount.

I bought one rear engine mount from e-bay a while ago. A few days after the installation, I found the mount leaked liquid. I had to replace it again.

[DaChoZn1]

I'm suspecting two things...

1. The IACV. I don't see a change in RPM's when my A/C is on or off. Then again, I still have vibration when the A/C is off. I don't want to spend $257 for a new one to find out that's not the problem.

2. Rear Engine Mount Control Solenoid. I did measure the correct voltage at the connector but how do you know if the solenoid working or not? Once again, I don't want to buy parts that may not fix my issue.





Modified by DaChoZn1 at 9:02 PM 3/19/2008

[billyrusa]

Disconnect the vacuum hose leading to the rear engine mount from the solenoid valve. If you have a vacuum gauge, use it. Otherwise use your finger to feel it. When idles is around 700 RPM, there shoud be vacuum. When idles is over 1000 RPM, there should not be vacuum.

[DaChoZn1]

Sounds easy enough. I'll try it when I get off work. I'll keep you guys posted. I appreciate everyones input and suggestions. Thanks again.


Modified by DaChoZn1 at 9:13 PM 3/19/2008

[johnlear]

How old are the spark plugs? Poor plugs can cause a rougher idle, and it's probably worth checking the lead resistance as well (high resistance leads will make a good plug act like a poor plug and a poor plug act like a very poor plug).

[billyrusa]

I should mention this in previous message. You should test the vacuum on solenoid valve after disconnecting the hose from it.

[DaChoZn1]

Ok guys, thought I'd give an update.

My car seems to have cleared itself. When I initially posted my thread, I had just completed putting my car back together and reset the ecu. I drove it around the block a few times for a test drive. At that time my idle was still rough and still have a lot of vibration.

Well after driving to work and back home (which is about 40miles total) it seem to have smooth out itself. I don't know if the ECU had to learn and adjust to the now clean EGR, IACV, Fuel Injectors and Idle adjustment? What do you think? Also maybe the new motor mounts had to settle and sit right? I don't know?

I did find my idle was lower than it should be. Set it to 800 RPM's and its alot smoother now.

All in all, my car is idling a whole lot better now. Once again, I appreciate everyones help. Hopefully this thread will help someone else with the same issues down the road.

[213374U]

Originally Posted by DaChoZn1

I did find my idle was lower than it should be. Set it to 800 RPM's and its alot smoother now.

Glad to help

[dan200]

"Once again, I appreciate everyones help. Hopefully this thread will help someone else with the same issues down the road." Quoted from above


It just did.

[chrisdab]

And it keeps on helping.

[Liner]

Originally Posted by DaChoZn1

I have a 96 Accord LX coupe, auto with 256,XXX miles on the odometer. I've replaced all motor mounts and tranny mount, cleaned the EGR, cleaned the injectors, cleaned the IACV, slightly adjusted the idle. Although it has somewhat improved, I still have a lot of vibration when I'm at a stoplight or in reverse. I gave it a complete tune up about 6months ago. The car runs like a champ at cruising/highway speeds. It just vibrates like hell when I come to a stop. It's really bad when I have the A/C on.

I'd appreciate any suggestions you guys may have. Thank you in advance.

I have a similar problem with my 1996 Accord with the 2.2 Vtec and AT. I have done everything above except replacing the motor mounts and adjusting the idle.

How do I adjust the idle?

The rough idle does not change when I put the car in Park/Neutral, which makes me think that it is not a motor mount issue.