car shuts off when a/c turned on, robs to much horsepower when on wiseman help !

[ShadeTreeDSM]

i've searched and posted this before and couldn't find anything. as of now i have my car set at 900-1000 rpm's and it idles fine both when i turn my a/c the engine shuts off, or when i'm driving the a/c feels like its robbing a lot of horse power. TPS is good and is adjusted according to hayne's manual, no vacuum or boost leaks, BISS screw is good, Idle Speed Controller is brand new and working, ECM is new. A/c compressor is new. the only thing that is not wired from the factory is the a/c condenser fan, i have a slim fan wired to a switch, but im not to sure that that'll be my problem, what do you guys think ? need expert help on this

 

[viprez586]

Sounds like a defective A/C compressor clutch - locking up.

 

[donniekak]

You may have to much oil in the a/c system, or the compressor is getting ready to die. Does the a/c blow real cold?

 

[BoostedBeaver]

Also make sure that your alternator is working and that the A/C is not pulling so many volts that it kills the motor.

 

[ShadeTreeDSM]

the alternator is working fine, it is charging 13-14 volts, the a/c compressor is brand new and it is blowing cold, im pretty sure it has enough oil in the system. i mean just because the compressor is brand new doesnt mean its good, but im assuming its good, is there a way to test it ?

 

[Lusion972]

it sounds like your A/C system is requiring to much electric power at start up. Most cars will slightly shudder when the system is turned on but the car is supposed to compensate for it with a slight change in rpm's. Your new a/c compressor, is it OEM or an autozone brand?

 

[ShadeTreeDSM]

bennett auto supply, local auto store.

 

[Lusion972]

edit: after doing some reading it would appear that the IAC is in charge of raising the rpm once a heavy electrical load is made such as turning the A/C on. Its not compensating for the load by raising the rpm so it might be malfunctioning.

 

[steve]

Unless you have an EPROM ECU and different software the simple fact that your idle is 900-1000 rpm's tells me that your ISC can't do it's job.

That might be because the IPS isn't working, that you have a 91+ ECU in the car or the harness had the pins swapped in the past to run one, that the drivers in the ECU are damaged, the wiring to the ISC is damaged, a bad ISC, or you haven't got the BISS set correctly.

I don't know where you find a real new ISC or ECU for a 90 anymore so I take it they are new to you not brand new.

 

[ShadeTreeDSM]

Unless you have an EPROM ECU and different software the simple fact that your idle is 900-1000 rpm's tells me that your ISC can't do it's job.

That might be because the IPS isn't working, that you have a 91+ ECU in the car or the harness had the pins swapped in the past to run one, that the drivers in the ECU are damaged, the wiring to the ISC is damaged, a bad ISC, or you haven't got the BISS set correctly.

I don't know where you find a real new ISC or ECU for a 90 anymore so I take it they are new to you not brand new.

ISC is brand new, got it from DSMISC.com and the ecu was rebuilt from a place down here in florida that rebuild ecu's for cars\ are from a 1990. when i first got the car it would idle correctly when the a/c was turned on, and if i plug in an ISC outside of the car i can see it working fine. so ECU and ISC are good.

the wiring to the ISC does anyone have the schematic of what color the wires are ? because when i wired it up there was 2 (10) gauge red wires that i mixed up but when i tested them with a muliti meter they both have a 5 volt source so i didnt think that was the issue. if anyone has the wire colors let me know, im pretty sure its wired up right though, i colored matched the wires.