Vibration with AC on (1 Viewer)

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Sometingwong. Check all fasteners. Belt tension? Compressor bearing? Belt type? Compressor lube?
 
I had rough vibration at around 800 rpm with my 97 LX450 with my AC on. For me, it was the exhaust had been re-welded across the rear cross member which was causing acoustic vibration that rattled the entire frame. Could yours be exhaust related? I saw you noted the Midwest so rust could be eating at fasteners. I had the exhaust re-welded and now there is only minor vibration and noise coming from the AC compressor. Not sure if the vibration that you are getting is the same as mine. However, in comparison to what I was experiencing, it feels completely different.
 
^^^This^^^. Check the exhaust system hangers. IME the rubber cushions split apart from age, then with the higher rpms when the AC is running ie: while parked or when at a stop light, there's increased vibration of the exhaust pipes due to the loose hangers.
 
I am experiencing the same vibration after a pretty extensive restoration which I replaced everything suggested with OEM parts. Has anyone been able to resolve this? It's very frustrating to spend so much time, effort, and money to have something that my wife points out when she's in the car. What's that noise? Why is it vibrating like that? Is something wrong?

Symptoms: Vibration in drive when stopped and AC is on. AC off or shifted to N stops vibration.
Work done: Rebuilt driveshafts, Replaced motor mounts, exhaust hangers, etc.
 
I am experiencing the same vibration after a pretty extensive restoration which I replaced everything suggested with OEM parts. Has anyone been able to resolve this? It's very frustrating to spend so much time, effort, and money to have something that my wife points out when she's in the car. What's that noise? Why is it vibrating like that? Is something wrong?

Symptoms: Vibration in drive when stopped and AC is on. AC off or shifted to N stops vibration.
Work done: Rebuilt driveshafts, Replaced motor mounts, exhaust hangers, etc.

Next time you are at idle with the A/C on and the vehicle is vibrating....(with brake still applied) very lightly depress the throttle and note at what rpm the engine smooths out. My guess is it will be just off idle at around 1,000-1100 rpm, yes?/No?
 
Next time you are at idle with the A/C on and the vehicle is vibrating....(with brake still applied) very lightly depress the throttle and note at what rpm the engine smooths out. My guess is it will be just off idle at around 1,000-1100 rpm, yes?/No?
Yes, right in between them.
 
Happens to my 94. Replaced the entire exhaust system which meant new hangers, and no more old cat heat shields. Made it almost unnoticeable- till I installed some tight fitting metal tech bolt on sliders that had very little space between the cats and the sliders. Mine definitely seems to be exhaust vibes- going to drill and dremmel a bit more space and see if it goes away.
 
Idle air control valve? It should help kick up the rpm when AC comes on. If it’s bad or dirty, it might cause this rough low idle. Explains why it goes away when you put in neutral…engine is under less load
 
I'm having a similar vibration issue on my LX, and it's gotten worse lately. My AC cools really well so no issue other than the vibration. At idle, in Drive, w/no AC, I'm at ~600RPM. However at idle, with AC on/compressor engaged, in Drive, I'm at 710-725RPM. My idle is too low with the compressor on, if I increase the RPM to the correct ~900RPM range then it smooths out. Also if I put it into neutral it also smooths out.

Has anyone tackled too low of RPM with the AC on? and what was your solution/things to try?
 
I'm having a similar vibration issue on my LX, and it's gotten worse lately. My AC cools really well so no issue other than the vibration. At idle, in Drive, w/no AC, I'm at ~600RPM. However at idle, with AC on/compressor engaged, in Drive, I'm at 710-725RPM. My idle is too low with the compressor on, if I increase the RPM to the correct ~900RPM range then it smooths out. Also if I put it into neutral it also smooths out.

Has anyone tackled too low of RPM with the AC on? and what was your solution/things to try?
My RPMs currently match yours with the 1FZ engine. My vibration went away when I replaced the exhaust cushions.

I will say that I occasionally see an RPM of 585 on a digital readout when the compressor kicks off.

I also screwed something up when changing the evaporator. I am getting blower fan noise/ vibration. Not sure if it’s my DIY gasket job between those components.
 
My RPMs currently match yours with the 1FZ engine. My vibration went away when I replaced the exhaust cushions.

I will say that I occasionally see an RPM of 585 on a digital readout when the compressor kicks off.

I also screwed something up when changing the evaporator. I am getting blower fan noise/ vibration. Not sure if it’s my DIY gasket job between those components.
I forgot to mention that I did check my exhaust mounts and everything looks good. Same thing with the compressor, no grind/wobbling from the clutch. This all leads me to believe that my issues is related to something else. I might try a different idle control valve and see what happens.
 
Swap the motor mounts?
Given mine is a diesel, it had a generally shaky idle vibe. I went for the engine mounts. The difference is night and day. The compression design hides the fact that the rubber is losing its adhesion to the metal part of the mount, I found my left mount and rubber were completely separate once the weight was taken off. FWIW, although an easy job to change, support engine properly or loss of fingers could be inconvenient.

Regards

Dave.
 

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