dirtbros808

My car info:
1997 HOnda Civic DX
1998 d16y8 motor swapped in
used AUTO d16y8 harness
CAT eliminated and STRAIGHT pipe welded in

I'm going to try to be as detailed as possible so bear with me:


I bought a 1997 Honda civic DX which had a d16y8 swapped in.
It had a high idling issue (around 2000rpm) first off so i tackled that & researched what i could off the internet. Found out the intake manifold was from a 99-00 civic and had the air injection ports that needed plugging, so i did so. It helped a little but didn't solve the problem. Come to find out, the car was an AUTOMATIC converted to 5-spd and still had the 3-wire iacv dangling (not even plugged in), while the 2-wire IAT plug was in the wrong place plugged into the iacv. Quickly fixed that and seemed to help a little once again. At this time I was thinking that the IAT connnector that was plugged into the iacv may have damaged either the iacv itself or ecu. So i changed the iacv. STILL a high idle. I tried to do the idle relearn procedure, however the idle still remained around 1500rpm. I adjusted the TPS and the idle settled down to around 1300rpm.

Figuring i could live with it i moved on...

Turn my a/c on to test it and the car's rpm DROPS like 1000rpms...goes from 1300rpms to 300rpms and the motor shakes while the car seems like its on the verge of dying out and i can hear the compressor clicking on and off every second to the rhythmic surge of the engine. I give it some gas to prevent it from doing so and the a/c is blowing ice cold..so i go for a spin around the block and it definitely causes the car to sputter and lose power at times with the a/c on. when i engage the clutch and come to a stop, the rpms dip to around 300 again and the compressor clicks on and off.

I can't figure out whats the problem...I think it could either be the IACV, ECU, COMPRESSOR, or overcharged system.

Here's what i've fixed so far...

changed iacv (with known good used one)
changed dizzy
changed dizzy wires
new spark plugs
did the 2-wire conversion for iacv
did the "code 91 fix" because my dx wasn't equipped with FTP sensor

The car seems to run fine with the a/c off. well with the exception of randomly throwing code p0505 for idle system malfunction which causes the car to bog out and do this weird bucking thing, but when i pull over and turn it off and start it right back up, it goes away. I believe its due to the nipple on the back of the intake mani for the cruise control being open...it was brought to my attention by someone today so i covered it up and did the idle relearn procedure. I got the idle to come down tremendously, but haven't gone on a test ride yet...

the ONLY other re-occuring cel light that is displayed is p0141 for the secondary o2 sensor because there is no hole for the 02 sensor, the previous owner cut out the cat and welded a straight pipe and didn't supply a bung hole. lol. for the o2 sensor.

So anyway, my QUESTION is does anyone know why my car's RPM's drop so low with the a/c turned on? I know a little drop is normal, but 1000 rpms is wayyyy unacceptable. I searched and searched but really didn't find any definitive answers....and do you think that the secondary o2 has anything to do with it? please help!!