I have a '93 Dakota Sport 4x4 with the 3.9 V6. It was running fine when I drove it the other day. 2 days later I went to start it and it would not fire up. Cranked fine, turned fine, but not firing up. Naturally, I went for the light codes to see if they had any insight to what the problem may be. I got zero codes. Not even the 55 showing the "end of codes". I had a helper turn it over while I sprayed starting fluid in the throttle body just to see if it was a fuel problem. Nothing. That only supports my theory of it being an electrical problem. Since the ECM is not putting out ANY codes I am at a loss. Does anyone have any ideas what could possibly be causing this or know of a way to test the ECM to see why it's not showing anything? All of my internet searches have come up with nothing useful. Thanks

 

Do you have spark?

 

No. There is no spark.

 

There's a lot of problems that will not throw a code
Just because you don't have any doesn't mean that all is well especially with the older trucks.

 

Look for bad grounds, test the battery, disconnect and reconnect the ECU, look for corrosion on the wire harness under the relay box on the driver side fender. There are a few splices there that go bad and need to be re-soldered to fix it.

 

Thanks. It's a new(er) battery. Just replaced last year and tests out fine. I dis and re connected the ECU. I tested the relays and the relay connections and they seemed fine. I'll start looking for bad grounds and bad connections.

 

It's not that it's not throwing a trouble code. It's not even showing the 55 code that states "end of codes". If nothing is wrong there should at least be a 55 code to let you know that all is well.

 

Does you check engine light up when you first turn the key to on? If not the bulb may be blown.

Did you use the correct procedure... Start with the ignition off. Within five seconds, switch the key on, off, on, off, on. (On is *not* start!)?

 

Yes, is does light up and goes out with the other lights. I've used the key on procedure many times before and I'm sure I'm doing it correctly. I just can't figure out why it's not showing even the 55, unless the ECU is bad. Is there any way to test the ECU?

 

Try the on off time faster, If you are to slow it won't show anything.