I have a 1994 Honda accord ex and recently dropped a rebuilt engine into the car. The check engine light is now on as well as the D4 light continuously flashing. The car will startup and drive however it idles high and inconsistent. I am an amateur at engine repair but I had a friend assist me and we are both out of ideas.

Any thoughts?

 

Scan for codes, they should say something.

 

Okay I checked the codes and came up with 6 quick flashes on the check engine light which continued to repeat and the D4 had 2 slow flashes.

 

A long flash indicates 10 but quick flashes are 1, you said you had 6 quick flashes.

CEL Check Engine Light

This indicates that your problem is:
6 ECT Sensor (Engine Coolant Temperature) defective circuit or unplugged / defective sensor

YAY you have a place to start and you didn't have to throw parts into it. Always a good idea to check for codes.

I've looked for D4 lights but I can't find a lookup. Probably somewhere else on this message board.

I'm pretty sure D4 lights have to do with transmission but I'm not sure. I would like to believe that a D4 light absolutely guarantees a trans issue and if it's not there your trans is fine but again that's a hard call to make.

 

The transmission code 10 is for the ECT sensor too.

 

Okay, I replaced the ECT sensor that connects to the computer, reset the ECU and drove the car for about ten minutes and the lights still remain. I beleive there are a couple of sensors that could be the issue but I am not sure where they are located. I have also noticed that only one fan seems to be running when the car is on or right after I turn it off. Any suggestions??

 

Here is a thread explaining the temperature sensors.

https://www.hondaaccordforum.com/for...sensors-39096/

Temp sensor B is responsible for the one fan turning on after the car is turned off. It has a green plug and on the engine block near the upper radiator hose. Try starting the car for a minute, then turn it off. If the one fan turns on, then you likely need to replace temp sensor b. Check the wiring first.

The engine coolant temperature sensor is under the distributor and has two wires going to it. That will cause the check engine light to turn on.

 

Thanks for the info PAHonda. Turned out to be the wiring for the ECT sensor. Once I replaced the wiring the check engine and D4 lights turned off, the fans are both running, and the idling issue was fixed as well.