I have a 89DX that I just put in an engine from a 90LX. When I got the car started, the check engine light came on. How do i pull codes from this thing? It still has the computer from the 89 in the vehicle.
I tried a forum search and also looked through the FAQ with no luck. Any help would be appreciated

 

do you have the ecu for the 90 lx?if not it will make the engine run inproperly without the correct ecu.and will throw a CEL

 

I was having that same thought. When I first tried to start it up last night, I had no spark. So I put my original distributor (from the '89) on and that's when she fired. I know the 90 ran with no CEL before I took the engine out.

 

try here
https://www.hondacivicforum.com/m_41699/tm.htm

 

I don't know whether the "jumper wire" method for retrieving CEL codes is applicable to an 89 Civic, but it may be worth looking into:

http://www.c-speedracing.com/faq/06.php

More importantly, if Alan is correct, any codes that you are able to retrieve may be uninformative until you have connected the correct ECU for your replacement engine.

 

Im going to switch ECU's tonight and see what happens. If I'm still throwing a code, I can use the jumper wire technique. Thanks for the help alan and ron

 

I think those have one or more LED's on the ECU itself that show the code. You do not need to apply a jumper wire, the light is active whenever the key is on. If it's a single LED behind a round clear window, just count how many times it flashes. The codes go up to about 20, that would be shown as flash 20 times, pause, flash 20 times, etc. If it has 4 LED's, the pattern they light up encodes a binary number from 0 to 15.

 

That's quite impressive knowledge mk378. It may be time for gacyota to bone up on binary numbers!

 

i would think binary numbers would make it more complicate. Flashing system isn't that bad at all

 

If that computer starts throwing binary codes at me, I'm just gonna do the wire jump method.