1G Can’t read codes

[DomOls]

I am trying to read my check engine codes, I seen a video on how to do it with a led light. I’ve been trying but every time I connect the wires to the light the light just stays on, it doesn’t blink. What is wrong and how do I fix it?

On a 1g I forgot to mention.

 

[steve]

A solid light usually means the ECU is dead. Does it start and run the car?

 

[DomOls]

A solid light usually means the ECU is dead. Does it start and run the car?

It is not running currently. It tries, and it gets spark. Just no fuel

 

[steve]

Good chance you'll need it fixed or replaced.
What are the specifics on the car and let's see the circuit board inside. (good time to fill out a profile on this car)

 

[luv2rallye]

Also try a small incandescent bulb. LED's turn on at very low voltage.

 

[steve]

I worry about the current draw an small incandescent bulb pulls.
If he was using a standard LED without a current limiting resistor the LED would quickly stop lighting as it burned up. A 12v LED only draws maybe 20-30ma where a small incandescent bulb could draw 100-200ma and may let the magic smoke out of the little transistor that drives the data line before the bulb burns out.

 

[DomOls]

Here’s the circuit board

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[enriquez2000]

You can find a shop that has the snap on obd1 reader for our cars. Its a hyundai adapter. Will even read auto transmission codes on the right device.

If you think you just arent doing it correctly

 

[steve]

That's a 1990 MD128624 Federal NA MT FWD ECU, not the MD166255 it should have It's had at least one of it's capacitors replaced but not of the corrosion fixed. It's not uncommon to find a replacement ECU since capacitor leakage was such a common failure.

I also see a hint of heat discoloration in the middle of the MCU chip that worries me.

I'd start looking for a good MD166255. They are the most common of the NA ECUs since they were used from 91--93. I suggest this so you have an ECU that matches the car and you don't have to swap any pins on the ECU connector for the Idle Position Switch (IPS) to work.

 

[enriquez2000]

I Have one....

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[steve]

You want the right case for it. I bet I have a few back home.

 

[enriquez2000]

You want the right case for it. I bet I have a few back home.

This one I have was a rebuilt one.. has a painted black cover. I have several backs dependii g on what his needs.

If you have one even better!

 

[DomOls]

So, once again nothing is really working. Unless it’s the wiring I don’t understand. I have checked mpi and ecu and the fusible links and everything checks out every pin has about 11-12 volts. The only concern I have right now is the new ecu does not turn the cel light on for a couple seconds. I apologize for not seeming to understand but I’ve checked everything that you’ve mentioned

 

[steve]

Where did you get the ECU from?
Was it a MD166255 this time?
Did you check it for leakage?

The CEL turning on for 5 seconds and then turn off is a sign that the ECU has turned on the MPI relay and powered up. Since yours isn't it's not going to do anything else interesting.

Almost all of this is still valid for a 1G 2.0L NT.

1G - 1G basic ECU MPI relay circuit function

The 1G DSM has two main circuits for the engine. The Multi Port Injection (MPI) circuit and the Ignition circuit. You must be registered to see element..The ECU is connected to both circuits but is powered from the MPI circuit and controls it. The MPI circuit also powers the MAF, CAS, ISC...

www.dsmtuners.com

 

[Mickey5055]

This is why I plan to get a working ecu and get a ecmlink so you can always look up code and etc.