jfls44

I have a 98 Accord EX, with 4cyl. auto transmission.
I am feeling a vibration in the steering wheel and in the drivers seat when the air conditioner is on, the two radiator fans come on and the idle jumps up some.
There is a slight vibration, hardly noticable, when the AC is off, so I know this problem is connected with ac running.
The vibration is really noticable when the two radiator fans kick in, the idle jumps from 650 to 750 (just guessing the rpms, the guage isn't clearly marked) the vibration gets worse.

Anyone have any ideas what this problem may be?

jfls44

40 views and not one reply??? Are you guys real technicians or just wannabees?

professorman

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jfls44 &raquo;</TD></TR><TR><TD CLASS="quote">40 views and not one reply??? Are you guys real technicians or just wannabees?</TD></TR></TABLE>

How about car enthusiasts? If you wanted a real qualified technician, maybe you should take your car to the shop and pay to have it looked on rather than trying to get free opinions on HT.

When your A/C kicks on, it amplifies the load on your engine, so whatever is causing your vibration just get more magnified with increased load. It does not mean that it is the A/C that is causing the vibrations. The radiator fans and the headlights also put increased load on your engine. Try turning on your high beam and turn them off and you see your RPM changes.

Maybe your engine mounts are bad, causing the vibrations from your engine to go to your car. Maybe your car needs a tune up and it is struggling to stay turned on because the spark plugs need changing. I do not know.

If the vibrations only happen in the steering wheel when you are driving withing a certain speed range, then it means that your tires need balancing. If it only happens when you are braking within a certain speed range, then your rotors need to be resurfaced.

Vibrations can result form a lot of different things.

jfls44

its definately related to when the idle jumps up, for instance with ac clutch kicking in. One thing I did notice, the radiator mounting is loose, I can shake it back and forth in its mounts, which seemed unusual. I will troubleshoot this later. Any ideas how this should feel, loose at all?

accord99power

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jfls44 &raquo;</TD></TR><TR><TD CLASS="quote">its definately related to when the idle jumps up, for instance with ac clutch kicking in. One thing I did notice, the radiator mounting is loose, I can shake it back and forth in its mounts, which seemed unusual. I will troubleshoot this later. Any ideas how this should feel, loose at all?</TD></TR></TABLE>

radiator mount are fine the radiator is supose to move alittle within the mount. listen to professor mans advice i agree with him.

jfls44

With the motor running, I unplug each spark plug wire and can see how it effects the motor running. One the no. 3 cylinder, when I unplug it, the motor will stall, it doesn't do this on the other ones. What could be causing that?

jfls44

I only said wannabees to get someone fired up enough to answer, I didn'tr really mean it...

accord99power

whens your last tune up? is it just the #3 cylinder? or do you have 2 or more plugs off when testing? and whats the purpose of that test? you should see motor shake really bad when plug off 1 cylinder. thats normal, not sure the point of your test of pullin plugs off.
i wouldnt throw that comment about tech out again, some of these people know more then anyone you take your car to. and they save you money so be nice just give it acouple days next time geez.

Elvis1977

What is the mileage? Look at both front and rear motor mounts for cracks, etc. I had to replace both of mine when I was getting vibration at idle at 110k on my 98 accord 4-cyl. Also, does the vibration get worse when you turn on your headlights and put the tranmission in gear?

noobking

What about his idle speed? I recall that my car used to drop to too low of an idle while I was in neutral at stops etc. This only happened when the car heated up to it's normal operating temp. The car would vibrate at the steering wheel and stick and the idle was choppy. Does anyone else think that the OP should increase his idle speed at normal operating temp.?

Just my 2 cents

professorman

I dont know. I am kinda hesitant to ever feel the need to change mine. I do not think mine has EVER been changed from the factory setting, and thus, if it ever needs to be increased, then it means that something is not running right to cause it to need a different setting. I would prefer to fix what needs to be repaired than to change it. If it was ever changed in the past, I would have no problem changing it again, because I wouldnt be guaranteed that the person who changed it put it to the correct setting.

This possibly could solve the problem if the idle speed is in fact lower than the stock setting, which I believe is around 700RPM at normal operating temperature. Is this correct?

99accordFX

Check your motor mounts, does it vibrate when in gear like reverse. I know the older hondas 94 and earlier always had a bad vibration due to worn motor mounts.

jdowen2

I had a problem with my 93. After poking around I found that the rubber had deteriorated on the crank pulley.