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Discussion Starter · #1 ·
Ok, i just finished my swap for a 1991 honda crx. I bought a ZC sohc motor for it, which is basically a 1.6 liter engine. I got it running but it runs real rich, bad enough to water your eyes. I looked in the chiltons and it said something about the pgm-fi is all controlled by the ECU. I checked the ecu and it showed codes but nothing I could get much info from (the blinking light kept giving me different codes). Would this mean that I need to replace the PM6 ECU or does this mean that I need to start checking all my sensors as I was going to try and adjust the a/f mix, but from what chiltons says, you can't manually do it like you could a carburator. It also has a slight misfire, but it does start up fairly well. the CEL doesn't go off....only if I try and use a PM5 ECU does the CEL turn off BUT it also won't start with the PM5 ECU. I am now clueless on where I should start. Can anyone help me that may have seen this before or been in the same situation and know what I need to do next!?!? thanks
 

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Discussion Starter · #3 ·
shux man, i wrote them down but i had so many of them and they weren't consistant that i didnt bring home the paper, i wont have those codes till tomorrow if I need them. I was hoping to maybe figure out the problem soon so when i getback to the car tomorrow I can spend some time diagnosing it ya know. crap, I remember 6-9-10-12 and I think 14, and then 3 and 2. I'll have to go get my paperwork. you got any clues?
 

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When you're running codes your ECU goes in to a limp-home mode that runs richer than normal. You'll have to fix those codes in order to get a proper air/fuel mix.

You might have an injector stuck open. Pull your plugs and see if its just one cyl that's black as hell. If so, swap injectors between a good cyl and the bad one to narrow down the problem to your fuel injectors.

Your timing might be messed up.

The car normally runs rich before it warms up. Take it for a drive and see if its still rich.

If you're using an ECU that is not programmed for your engine (i.e. using a D16A6 ECU on a different engine) your fuel/air mix WILL BE MESSED UP REGARDLESS.

Good luck.
 

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Discussion Starter · #6 ·
OK, here are the codes that the computer flashs.

3-6-10-13-20

Does anyone know where I can find a code book or trouble shoot page?

I am using a PM6 ecu that came with the car. I have a SOHC ZC motor. If you know this is the wrong ECU, please let me know. I will go get it if its wrong. I am not sure how to test that either
 

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Discussion Starter · #7 ·
the only other thing I can think of is what if I try another intake off a known working engine that I have, thats been just sitting for rebuilding purposes?
 

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Discussion Starter · #10 ·
OK, from what I have learned today is that I need to do something called a K-test. I guess its to check and see if I have power at MAP sensor and if so, the ECU is ok, if not, the ECU needs to be replaced. Does anyone know more about this?
 

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Discussion Starter · #12 ·
well, i was able to get all the code trouble shooting, I believe. I guess I just need to sit back and do every test it asks for and make a decision from there, crap!
 
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