zc engine swap trouble

I recently swapped a zc engine into my 91 civic. It started and ran fine for several hours, lots more power. After driving it a while it started to stumble on acceleration. It seems to run better when it is cold, but it still isn't right. Once its warm it bogs really bad. The ecu is flashing a code 20 (electric load). Under the drivers dash there is a quiet beeping type sound when I turn off the ignition. It seems the wiring is wrong but I checked and it looked good. If anyone's got some Ideas of what I might check or try the info would be appreciated.

If you didn't solder your connections, you should. I had trouble with my swap (not the same as you are describing). But in the end, it was because of the butt connectors that were used in converting the DPFI to MPFI. After everything was soldered, all was good. Hope this may useful in your situation.

look for the ground wire near the thermostat. make sure it's tight... or look at the TPS it may be bad test it.