so i got a 90 ef si with an ls-vtec. i had the motor in my da9 and i threw it in the hatch. my problem is kinda strange i have never seen this problem ever in my life. when i first did the swap the car started and idled rough, it also threw me an 02 sensor code and iac code... i double checked my connections and were all good.. i reset my ecu and now the car will not start. Here is my main concern. i know how an engine works and what to listen for right before cranking, i turn the key on and hear my main relay click and fuel purge is strong but will not start, when i shut the ignition all the way off and pull the key out i still see the Brake light the battery light and oil light on but very dim... i have no clue on what this is ive looked everywhere from honda swap to yahoo to ef civic everywhere... any help is highly appreciated thanks

 

check your fuses

 

check grounds

 

ef yu - what fuzes am i checking? the under hood ones? under dash? or those little black relays?
theft 24 am i checking the engine grounds?
thanks guys

 

What engine harness are you using?

 

the multi point si harness

 

mainly check the ones underneath the dash

 

So engine harness matches chassis harness.
Check your engine grounds,clean and make sure they are all good.
It sounds like you have something backfeeding power into the car.

 

so i just checked all grounds and there all tight and good, i also checked all fuzes and here is wat i found out, when i turn the key off the lights stay on but when i unplug my main relay it turns off... i have no clue whats goin on

 

Main relay could be shorted somehow,try changing it for another if you have one see if that helps any.

 

ive swapped em out with a da9 and another ef one :/ and still does the same thing

 

do u have spark? is your ecu light coming on when turning key to on?

 

yes i do have spark and my ecu is good too

 

Check for a short in the wires to the main relay.

 

can you tell me where all the main relay wires lead? i ask so i know what direction to unloom in the car harness

 

Double check the ground on the thermostat housing. This happened to a friend of mine and we couldn't figure it out for the life of us. Turned out that a small wire was not bolted to the housing.
Also if for whatever reason you have a fried harness, I have an extra 90-91 civic si harness forsale

 

i inspected my harness fully, how many wires are supposed to be on that thermostat housing ground? i see 4

 

also remove the dizzy cap to see if the rotor screw backed out?

 

There should be a single black wire that bolts to it with a 10mm bolt. It's easy for it to get tucked back and hidden on the harness if you don't know were it is

 

thanks for all the help fellas!!!!! problem found..... really bad short in the number one injector clip wire (brown)

 

good job.