I've had a few fb's over the years, the gsl-se I have now is the first one I've ever had with functioning AC. I never use it because it really really ROBS power from the engine. I would expect some loss, but it makes the car feel sick. When trying to cruise before 5th and 6th ports open (up to around 4k rpm) I get the "bucking" or "surging" like the rotors aren't coordinated or something, and it usually dies if you jump off the gas to come to a stop. It just sounds completely different also, and above 4k rpm, it still seems like I've lost at least a whole third of all available hp.
My car has full RB exhaust, DLIDFIS, K&N filter cartridge, brand new properly funtioning fan clutch, rest just about completely stock. Not using the AC, this car runs REALLY good compared to all the others I've had. It will fly to shift buzzer and still feels like it's got more, and has zero issues with idle or anything else. Can the AC belt be too tight? Could there be an issue with ac compressor itself?
Input is appreciated, I love this site!

 

Perhaps there's a problem with the compressor. Sounds like it's getting hung up somehow inside. bad bearings maybe. I don't know what the inside of the compressor looks like so I'm just speculating.

 

It does sould like a worn compressor.

 

If the system still works, the seals are still good. Thats not likely if there's a problem with the compressor.

AC takes a lot of power. It's a big percentage at idle, resulting in a 2 - 300 rpm drop easy!

Kick off the AC when you want serious power! A switch on the gas peddle to kill AC at full throttle would make it mindless.

Always liked the AC on the hot days, but yea, you can feel the power drag!

 

Many modern cars (like BMW) have a switch that cuts off the AC at 80% or so throttle for this reason.

 

Let be get more specific - the clutch and bearings on the compressor may be failing. Listen closely to see if you hear some rattling when the compressor kicks on. Almost a grinding/rattle sound - goes away when fully engaged. And the AC will work fine untill complete failure of the clutch. The issue is added resistance on pully - the pump will still function but just drag your motor. A 200 rpm drop is normal - any more and parts may just be worn out.

 

Have you recently serviced you AC, in have you added any freon? If the system is over charged it will cause the compressor to turn much harder.

 

If the system is undercharged it will run the compressor continuously.

If your seeing/hearing the compressor clutch constantly engaging over and over then
you have an AC issue. The compressor should come every 30 seconds or minute
to keep the pressure up but if theres a leak or low refrigerant it will come on
all the time and really put a drag on the engine.

Sounds like you need an AC checkup before anything else to see whats up

 

Thanks for the input, guys. I have never had the system serviced since I've owned the car ~5 years. I don't hear any rattling noises, but never popped the hood and listened, either. It seems to work really well(cold) but I have never used it for long. If I am driving at ANY rpm in ANY gear and just hit the button to engage the ac(as long as fan speed is on at least 1), it throws me forward so hard my seatbelt locks. I can't even climb long highway hills and stay in 5th gear at highway speeds while using ac! I guess before I just remove it all, I'll have the system checked out somewhere. Thanks again.

 

thats strange. the a/c on my SE does make the car lethargic when acelerating but nothing neck snapping...

 

IMHO,

You don't have a "A/C" issue but a running issue.

Have you verified that you 5th/6th port actuators are operating properly?

TPS adjusted properly?

Also may have vacuum leak(s). Spray the area where the Block off plate for the ACV is and see if the idle picks up at all.

When you turn the A/C on the IACV(Idle Air Control Valve) should boost the idle up to compensate for the drag created by the A/C compressor. If it does not then you need to trouble shoot this per the FSM.

 

I always thought that if your A/C is undercharged, the low pressure switch won't allow it to run the compressor. That's the way it seems to be with the cars I have.

 

Thanks for the reply, Doc...5th and 6th ports are absolutely working properly, I spent a few days the other summer taking all that stuff apart and cleaning everything to install the pineapple sleeves and it made a big difference in how the car felt afterward (they were seized before). I've checked the TPS, and I've checked for vacuum leaks, and the engine does speed up to compensate when ac is engaged, (~150-200 rpm) and it will idle and everything, but it really really wants to just shut down if you jump off the gas to come to a stop. Thanks for the suggestions.

 

Modern cars have these switches but in th 80s I don't think they existed. Thats
why on older cars a low charge can burn up a compressor cause it keeps trying.
Even my 93 Navajo SUV will cycle the compressor constantly when the charge
is low.

 

SE's do have a low-pressure switch, it's located on the low pressure line coming from the cabin (firewall) back to the compressor on the driver's side of the engine bay. It has a nut-shaped fitting and two wires that go into the harness on that side.

If pressure is too low to operate, it shuts down the compressor via the solenoid which engages the A/C compressor clutch, if the clutch won't lock down, the compressor doesn't turn, which saves the compressor if no lubrication is present.

 

My three 84 SE's and 84 and 85 GSLs all have the inline switch like LD mentioned above. My old 83 GSL and the 85 GS parts car have the pressure switch on the receiver/dryer under the rubber plug in the cover in front of the radiator. I think all 81-85 have a pressure switch in one of the two areas mentioned. Pressure has to be pretty low to shut down the compressor. When the pressure starts to drop the compressor stays on longer and longer until it stays on continuously then the pressure switch kicks in to shut it down.

 

So, what I've gathered from everyone's thoughts...1:No, my belt couldn't be too tight. 2:If the system is overcharged, it will cause more resistance @ comp. pulley.
3:If system is undercharged, comp. will run all the time, and it normally wouldn't.
4:comp. itself may have bad bearings or whatnot for it's pulley.
As far as me testing anything, can I check the pressure in the system to know if it's too much or too little? Just find a schraeder valve on the ac system somewhere and use a tire checker? Do this while car isn't even running, or only while ac is engaged? What pressures are "normal", what should I read from a healthy system? Thanks again, guys.

 

http://www.harborfreight.com/catalog...&q=A%2FC+gauge

Don't know if it has been retro fitted to R134A or not but would have a sticker somewhere and you would have a large blue and red cap on the fittings on the compressor if it has been.

As far as readings go the gauge comes with the instructions.

It is checked with the Engine running and A/C on.

 

Thanks again, Doc. I guess it wasn't retrofitted since everything looks like it's never been messed with and there aren't any stickers or red/blue caps anywhere...Next time I'm by the H.Freight I'll look into this.

 

If it has not been retro fitted with R134A then the gauges at Harbor freight will not work. :-)

Take a picture of the high/low side fittings on top of the compressor and post them up. That way I can see if it has been changed or not.