How can you test an ECU for a 1993 Civic ?

[Cd]

How can you test an ECU ( "computer" ) for a 1993 Civic ?

I have been talking to a guy at a Honda Civic forum almost five months now, and we can't figure out the problem with the car.

My car has an electrical short somewhere, but im beginning to suspect the ECU is at fault.

Is there a bench test to see if my ECU is dead ?

When i try and start the car, i see the CheckEngineLight come on, and when the car decides to run, the CEL performs as normal and goes off after a second or two after starting*.


I had read that this is a good sign that the CEL is still good, but I also read elsewhere where the guy performing the test got a CEL but the ECU was still a dead part.

( *The car is now no longer starting at all )

1993 Honda Civic DX 1.5 L Automatic ECU code # 37820-P06-A51-741-627244

[Cd]

I could go into detail on the cars symptoms and what all that i have replaced in the car, but for now I'm just concerned about the ECU.

I posted here before on Ecomodder about the issue and go some excellent advice from OldMechanic , but rather than revive a long thread i thought i would cut to what i think is wrong with the car since i have tested pretty much everything else.

[2000mc]

from what you describe, i wouldnt suspect the ecu at this point. done any other diag? check spark? fuel pressure? any dtc's?

[2000mc]

priced out an ecu?

[Cd]

Originally Posted by 2000mc

from what you describe, i wouldnt suspect the ecu at this point. done any other diag? check spark? fuel pressure? any dtc's?

Yes. I'm pretty sure its either the ECU or a wire deeeeeeeeeep inside the dash.

I have removed parts of my dash already and its a royal pain to try and find a dead wire in a huge spagetti mess of wires.

[Cd]

Originally Posted by 2000mc

priced out an ecu?

$ 298 at AutoZone . None at the local junkyard.

I looked online to see if there was a similar post somewhere and a guy suggested a way to test the ECU is to find another running 93 Civic and swap in your ECU. If it runs you know its good.

Great idea !

Hmmm....but i don't know of anyone that has a 1993 Honda Civic DX besides myself.

Oh ...and once you buy an electrical part and install it, you cant take it back.
Im tempted to buy one plug it in and test it. If it doesn't fix the problem and i take it back how would they know i plugged it in ?

But that would be dishonest eh ?

[2000mc]

well you dont have to be able to get to the wire where the problem is at, you just need to be able to test at both ends of the wire. test for continuity, and short to ground, if there is a problem and you cant access the wire where you suspect the trouble, bypass that section with a new wire.

[2000mc]

have a link to your old thread on the issue?

[drmiller100]

do you get spark or fuel ?

ecu's going bad is pretty rare, but does happen on occasion.
much much more common is pickup or ignitor in distirbutor, and fuel pump.

first question.
do you have spark.
second question.
are the injectors firing?

[Cd]

Thanks guys. I really didn't expect so many replies ....and so quickly !

I swear I still have not received but three or for replies at one of the Civic forums I posted at over four or five months ago. The other forum has ONE guy that made an effort to help me out.

If I ever have a car problem I think ill post here first !

I'll go ahead and try and make a more consolidated post tomorrow so you guys don't have to read so much .


Ill also post a link to the various threads as well as link to the Civic Forums page.