420A 2gNT ecu

[DSM Solar]

I have a 97 Eclipse RS with a stock 420A engine and ECU. I realize this is probably a novice question, but? Is the ECU plug and play? How exactly does it work in conjunction with the crankshaft, and camshaft sensors? Will a bad knock sensor also cause a no start? Fuel pump and ASI (I think?) relays are good. I think I have a bad ECU, I bought a used one from a local yard. Plugged it in, and nothing. So I returned it. They said it needed to be "flashed", and that only the Mitsubishi service center could do that? I am trying to learn as much as possible about my DSM to be able to troubleshoot and fix it myself instead of taking it to a mechanic. Any information will be greatly appreciated.

 

[lumberjackracing]

The crankshaft sensor controls the timing of spark and the camshaft sensor controls the timing of the injectors. The computer does not need flashed but depending on what year the ecu is you might have to swap a couple wires around to make it work. Do you know which year ecu you bought.

 

[DSM Solar]

I don't know what year the ECU was, but the last part of the serial numbers matched. I don't know enough about the ECU to try to swap the wires. Maybe it was a bad ECU? I think I am going to send it off to a company that tests them and refurbishes them if necessary. Its gonna cost approximately $250. Thank you for the info.

 

[DSM Solar]

Just purchased a new ECU and installed. The place i bought it from told me there was no need to flash. That the ECU was plug and play. Still I have no spark at the coil. I replaced the Crankshaft sensor which was what the ODB II was indicating faulty originally. Very frustrated, is the ECU plug and play? any suggestions??

 

[silvreclips]

Through the years some of the wiring was changed on the harness. You have to run an ECU from the same year car you have. There is also other things you can check, do you have power to the injectors? Does the fuel pump prime when you turn the key on?

 

[boost97gst]

On the 420a there was a change in wiring from the 2ga to 2gbs iirc. The connectors in a few places are different so either you redo the wires or get the correct map,iat,cps,cas etc. etc. units and wire them in for THAT cpu. I had to do this on an engine swap once, or i inadvertantly bought a different harness. Either way, i had to swap and resolder sensors for it to work porperly. Thats been about 4 years and has long escaped my memory at this point.

 

[95talongirl]

Check the cam sensor, as well. I've seen cars, esp. Chrysler products that would throw faults for the crank sensor, when in reality it needed the cam sensor. Both of those sensor need to be functioning properly in order to get spark.

 

[TwiztedEclipse]

Is your Whole problem no spark? Try replacing the vehicle speed sensor, My car had the same problem mine is m/t thought dunno about yours. after i fixed that it ran fine i mean started up and i had spark again. apparently the signal goes through that before hitting the cam and crank so if you have signal there according to a diagnosis computer at the cam and crank then forget my idea .

 

[DSM Solar]

thanks for all the great info. Im gonna replace the vehicle speed and camshaft sensors hopefully that does the trick.

 

[DSM Solar]

Finally, after almost a month of struggling..My Eclipse runs again!. When I first read the scanner code for a faulty CPS, replacing it didn't fix the problem. This was because it was a misleading code. What happened was, the hydraulic belt tensioner went bad. You could not tell from looking at it through the access plate on the cover. The belt wasn't torn and there was still some tension on it. The timing then was off, and that was the cause of the lack of signal from the CPS, and CAS. I know it was a rookie mistake to not check the timing the first time up. Thank you for all your advice, learned a lot from it. Happy to be back on the road