Rpm

[norwegianvette]

My 1993 idles at 800 rpm when warm, is that to high. She idle nice, just high.

Thanks

 

[SnakeOiler]

Manual or Automatic?

 

[ex-x-fire]

Sounds alittle high, may have a vacuum leak. Poss. the o-rings for the injectors or a vacuum hose has a crack. Another thing you can do is thoughly clean the throttle body & iac passage.

 

[norwegianvette]

Manual or Automatic?

Automatic

 

[joshwilson3]

I think my 89 idles at 750 when warm.

 

[norwegianvette]

When switching off the heater the rpm drops. Is that normal? Anyone tried to put it on/off when ideling and have the same?

Steve

 

[boomdriver]

When switching off the heater the rpm drops. Is that normal? Anyone tried to put it on/off when ideling and have the same?

Steve

IAC should adjust the idle speed whenever the A/C is turned on/off but not the heater. Anytime the a/c compressor is running or turned off the idle should adjust itself.

 

[joshwilson3]

IAC should adjust the idle speed whenever the A/C is turned on/off but not the heater. Anytime the a/c compressor is running or turned off the idle should adjust itself.

The compressor clutch engages wether it is on AC or Heat in my 89. I think it does the same in my 3rd gen.

 

[norwegianvette]

When i say off i meen the whole heater/AC system. I have the electronic controll unit with a off position. When i turn the unit off the rpm drops.

 

[John Robinson]

Your idle RPM is the same as my 93. When the heater is on the air conditioner runs continuously to prevent fogging of the windows. This creates a heavy load demand on the alternator and so the ECM adjusts the fuel trim to maintain the current needed. This load demands so much hp that under hard acceleration the ECM automatically turns the air/heater off to improve wot performance.

I believe the rpm is a little higher when the ac/heater is on because the alternator needs to run at that speed to keep up with the electrical system load.

 

[joshwilson3]

Your idle RPM is the same as my 93. When the heater is on the air conditioner runs continuously to prevent fogging of the windows. This creates a heavy load demand on the alternator and so the ECM adjusts the fuel trim to maintain the current needed. This load demands so much hp that under hard acceleration the ECM automatically turns the air/heater off to improve wot performance.

I believe the rpm is a little higher when the ac/heater is on because the alternator needs to run at that speed to keep up with the electrical system load.

Could you disconnect the compressor clutch and run the heat? Like if your front compressor seal is leaking or if your compressor is on its way out, so you don't want the compressor running, but would like to have heat during the winter.

 

[John Robinson]

I don't know because the compressor is an integral part of the whole system. Maybe someone else can chime in here that has knowledge about what controls what.

 

[toptechx6]

Could you disconnect the compressor clutch and run the heat? Like if your front compressor seal is leaking or if your compressor is on its way out, so you don't want the compressor running, but would like to have heat during the winter.

Actually the current practice of running the A/C compressor even with heat on was implemented for two reasons, as John mentioned it removes moisture from the air which helps keep windows clear. The second reason is that when A/C first came into common use the compressor would often sit idle for months at a time during the winter when owners needed heat, since an oil film contributes to the integrity of the front seal many cars would develop a leak there due to lack of compressor engagement until the manufacturers adopted the current practice.

 

[joshwilson3]

Actually the current practice of running the A/C compressor even with heat on was implemented for two reasons, as John mentioned it removes moisture from the air which helps keep windows clear. The second reason is that when A/C first came into common use the compressor would often sit idle for months at a time during the winter when owners needed heat, since an oil film contributes to the integrity of the front seal many cars would develop a leak there due to lack of compressor engagement until the manufacturers adopted the current practice.

I know I removed the frisbee and put a new belt on my 89, and the front compressor seal started slinging oil on the hood right after that. So, I haven't been using the AC. Another car I noticed the compressor making a noise, so I figure it is on its way out. I may try disconnecting the clutch and running the heat in the winter and see what happens. I know in the winter if I run defrost and the car isn't warmed up yet, then that fogs my window up, then when it warms up it removes the fog caused by the AC.