Looping / Surging Idle only when A/C is on

[djur]

I have a 2nd gen ranger 1989 to be exact, 2.9L... Whenever I kick the A/C on the clutch engages every 3 seconds or so, drops the RPMs down to 600, disengages, revs back up, and kicks back in... The result is a really annoying looping which causes the vehicle to die if the clutch is let out during the down part of the cycle... When it does this the voltage appears to drop below 12 volts according to the voltometer. I'm not sure if the A/C compressor is worn and putting too much strain on the engine to maintain its idle... The only code I pulled doing a KOEO testwas 84... an EGR code. I'm aware this might be a vacuum problem... but pulling vacuum lines in the engine compartment yielded no obvious culprits... I would hate to tear into the dash looking vacuum problems if it turns out to be a bad compressor, alternator, IAC valve, EGR valve... etc.

Some insight please.

 

[dla]

I have a 2nd gen ranger 1989 to be exact, 2.9L... Whenever I kick the A/C on the clutch engages every 3 seconds or so, drops the RPMs down to 600, disengages, revs back up, and kicks back in... The result is a really annoying looping which causes the vehicle to die if the clutch is let out during the down part of the cycle... When it does this the voltage appears to drop below 12 volts according to the voltometer. I'm not sure if the A/C compressor is worn and putting too much strain on the engine to maintain its idle... The only code I pulled doing a KOEO testwas 84... an EGR code. I'm aware this might be a vacuum problem... but pulling vacuum lines in the engine compartment yielded no obvious culprits... I would hate to tear into the dash looking vacuum problems if it turns out to be a bad compressor, alternator, IAC valve, EGR valve... etc.

Some insight please.

Seems like I remember there being a sensor that indicates the compressor is engaged. When engaged, the ECM will increase the idle RPM to compensate for the increased engine load. If the sensor is bad, then I suppose the AC compressor would drag the engine down noticeably.

 

[djur]

Read the codes.. here are the results:

KOEO

IIIIII IIIIIII
IIIIII IIIIIII
67

I
On to continuous

IIIIIIIII IIIII
IIIIIIIII IIIII
95

KOER

I I I
111 - System okay - huh?

I tested the KOEO a 2nd time after doing the running test... This is what I got:

IIIIII IIIIIII
IIIIII IIIIIII
67

I

II IIIIIIIII
II IIIIIIIII
29