93 Ranger EEC Code 411

[93redranger]

Hello everyone, I have a few issues I would like some help with. This is my first time to post on a forum with a question so please let me know of any mistakes and ill fix them up.
I have a 1993 Ford Ranger Extended Cab (2.3L) EEC-IV Cross Fire Ignition System with a 5 speed manual transmition.
I cleaned the engine with some good degreaser and a pressure washer so I could do a retrofit on the A/C system. After I cleaned it I noticed that the engine was running a tad bit on the rough side during the Idle, not enough to really notice but enough to make the engine vibrate more than it was, and it does a slight serge after it sits for a few minutes, only a few RPM but it is noticeable to me. I did notice a small piece of (1/4” OD) hose under the engine after I washed it so I looked for a vacuum leak, I could not find any missing hoses in the vacuum system so I started the engine and sprayed (starting fluid) around and did not notice any changes in the Idle. The engine was doing this before I did the A/C retrofit and I have not noticed any major change after I have completed the retrofit other than the extreme increase in fuel usage, not sure how much worse it is but the gas gauge sure moves down a lot faster now, not sure if this is due to the addition of the A/C or the rough Idle problem or both. I did a KOEO self test and the EEC-IV reader shows a 111 (pass) so I done a KOER test and it pulls up only a code 411, I have been unable to find how or what to test on this code. I did do an Ohm’s check on the IAC solenoid and was getting 12.6 Ohms, according to the Chilton book I have that is a good reading.
The second problem is now that I have completed the retro fit on the A/C system I am puzzled on the results, the tag on the evaporator shows the system to hold a 1.75lb max system charge but when I added 7.5oz of Oil (I was told this is the correct amount from Autozone) and the 21oz of R134 I added (was told this is the correct amount from Autozone) My low side pressure (with compressor running) was way up like over 100 psi and as you guessed it the compressor was making a nice little scream. So I removed the excess pressure to a low side pressure of around 30psi (with compressor running) and a high side of around 190-200 with a ambient of 85-95 deg F. the issue I have is the system does not seem to be cooling much and I need to verify the correct amounts of 134 and oil to use, or is there anything I missed. Any and all help would be great, if more information is required please let me know.

[Davescort97]

Welcome to AF!

I would take the IAC off and clean it inside with some carb cleaner.

Code 411 is cannot control rpm during key on engine running low rpm check.

When you turn the controls to MAX AC does it get any colder. If not, you need to add a little more freon.