91 D15z1 swap Idle probs.
 

I finished my swap last week. I test drove it around my neighborhood and it runs fine. However, under any electrical load it bogs down and runs rough. It runs smooth when I start it and after it warms it runs a little ruff then also. It even runs ruff when I press in the cigarette lighter.

first of all, not a honda guy.

that sounds like an electrical problem. is it the original alternator? maybe it is bad and when loaded, it loads down the voltage. maybe the battery is bad. I have heard of a bad battery looking like a bad alternator.

I would blame the electrical system first unless everything has been changed out. it is kind of bad that you can't even push in the cigarette lighter without issues. I was actually going to ask if you had a huge setereo but that doesn't seem to be the case.

you could also use a clamp ammeter to see what is being pulled from the battery/alternator if you think you may have some sort of short circuit.

there again, not a honda guy so can't say for sure.

good luck

It could be that you forgot to connect the wire that goes from the alternator to the ECU that tells it to idle up when there is a heavy electrical load.

I am suspecting an ELD (Electric Load Detector) problem as well.

What Model Honda did you swap into?

I swapped it into a 91 HF. I checked the alternator and its fine. I cleaned all the grounds while I was putting the motor in. Can the eld be bought separate from the fuse box in these cars? This is my third swap on a honda and this is the second time I've had this problem. Also, when I go to start it after it hasn't been started in a while the motor turns a few times as the the fuel has to be pumped from the tank. I don't know if its related but the other car I had the electrical problem with had that same problem. It was a 93 accord the I put a jdm f20 into. My uncle and I went through the service manual and tested every component for three weeks and found nothing. By the way the battery is fine too.

ELD is an integral part of the under hood fuse panel.

Are you allowing the ECU to prime the fuel pump and do the self test before engaging the starter? During the self test the CEL light illuminates and the fuel pump primes for 2 seconds, once the CEL is off then you can start the car.

Are your battery terminals corroded in even the slightest manner? I just got done fixing a problem like this on an 89 CRX Si. I made all new ground cables and replaced the battery terminals with new terminals/cables from Checker Auto.