Car bucks under accel when A/C comp is on.

[Marccus]

Car bucks under acceleration when A/C comp is on.

Replaced the compressor, suction line, accumulator, and discharge line and orifice in my ’89. When the compressor kicks in and only under acceleration, the car bucks and I hear squealing (I assume from the belt). When I am just cruising at the same speed or idling the A/C works fine – that is when it decides to kick in – must be the switch that’s causing that problem.

Is my NEW factory Ford compressor damaged? Ugggggghhh, if true. Costs me over $300. Is the belt too tight or too loose with squealing/screeching?

Can anyone diagnose what is wrong with the symptoms I’ve described?

 

[ViPER1313]

I could always feel the AC compressor cycling with my 92' as well - it never bothered me that much. I always figured that the R134a in the system was causing the compressor to work harder.

Belt squealing - tighten it.

 

[Marccus]

Yes, but my car bucks BADLY. So badly, that you can't continue to drive it like that.

 

[techi14]

Perhaps the ac compressor clutch might need adjusting??? just throwing that out there

 

[Marccus]

Well it is supposed to come correctly gapped from the factory. But we know how that goes. To adjust the gap do I have to remove it completely from the car? What is the correct gap?

Thanks for the suggestion. It seems really plausible.

 

[rubydist]

on my 92, every time the a/c compressor kicks on, the pcm pulls the iac open some, and it bumps the engine speed up a little - around 100 rpm at idle. you can feel this as you drive the car at steady throttle. this is much more noticeable with the new iac than it was with the old, sticky iac that I replaced.

if your a/c cycling switch is bad or if the a/c refrigerant is low, so it kicks the a/c on and off every couple seconds, it can be very annoying to drive. I would take a good look at the refrigerant pressures and make sure the cycling switch is okay.

 

[SHOMON]

Also an idle relearn might help. Especially if the last time it was done the A/C compressor wasn't cycling.

 

[mrecoolgar]

Yep, as stated low on refrigerant, an ac compressor that’s on the verge of seizing or the intake air valve.
When that happened to me it was the iav.