DS-MAP

ecu repair (not just caps)

Presterone

  • *
  • 94
    • Galant VR-4
    • 1990
    • Head: 1G (large ports)
    • Motor: 4G63 2.0L
    • Turbo: FP 16G
ecu repair (not just caps)
« on: February 01, 2015, 07:00:07 PM »
Can anybody here take a look at my ecu and possibly repair it? I've had the caps replaced and EPROM socketed but the ecu still doesn't work as in it doesn't ground out a circuit to the mpi relay and it doesn't turn my CEL on with the key on engine off. There is no obvious burning or melting to the board so I'm not sure what's going on. My non EPROM turbo ecu runs the car fine and the CEL turns on so I'm assuming its the ecu that's faulty and not the car.

Re: ecu repair (not just caps)
« Reply #1 on: February 01, 2015, 07:17:46 PM »
Does everything else work on it just no CEL / MPI relay ?
AMP 2 Corinthians 8:21
For we take thought beforehand and aim to be honest and absolutely above suspicion, not only in the sight of the Lord but also in the sight of men.


Presterone

  • *
  • 94
    • Galant VR-4
    • 1990
    • Head: 1G (large ports)
    • Motor: 4G63 2.0L
    • Turbo: FP 16G
Re: ecu repair (not just caps)
« Reply #2 on: February 02, 2015, 05:55:15 AM »
Yea I took the wiring diagram and checked every circuit related to that ecu and it came down to the ecu not grounding out the mpi relay. Its kinda neat how the ecu grounds it out and then the relay loops power back to the ecu.

Presterone

  • *
  • 94
    • Galant VR-4
    • 1990
    • Head: 1G (large ports)
    • Motor: 4G63 2.0L
    • Turbo: FP 16G
Re: ecu repair (not just caps)
« Reply #3 on: February 02, 2015, 05:57:26 AM »
I also should mention I swapped this faulty ecu unto my running driving gvr4 (well aware of the risk) and it performed the same way, no cel and a crank no start.

Re: ecu repair (not just caps)
« Reply #4 on: February 02, 2015, 01:28:57 PM »
Did you check the mpi traces ? It is basically internal logic that the ECU self powers on.

I don't think it's code that tells it to relay over the mpi and power itself on, I could look at it for you, but I'm sure it's a trace that's bad just hard to see it. Use a volt meter and start mapping out the trace.
AMP 2 Corinthians 8:21
For we take thought beforehand and aim to be honest and absolutely above suspicion, not only in the sight of the Lord but also in the sight of men.


Presterone

  • *
  • 94
    • Galant VR-4
    • 1990
    • Head: 1G (large ports)
    • Motor: 4G63 2.0L
    • Turbo: FP 16G
Re: ecu repair (not just caps)
« Reply #5 on: February 02, 2015, 08:17:46 PM »
I did swap the mpi relay as well with a known good one. I only did a quick test for voltage, I did not resistance test traces or check for voltage drop to pin point the exact issue. If you would send me a PayPal and a price I'll happily ship it to you if its a reasonable price for diagnostic work and then maybe repair of you wanna give it a try? Or should I just cut my losses and buy a socketed EPROM ecu?

Re: ecu repair (not just caps)
« Reply #6 on: February 03, 2015, 02:34:10 PM »
I don't repair them professionally, I would only ask for shipping both ways if you want me to look at it.

I can also bench test it on my. Jimstim setup :-)
AMP 2 Corinthians 8:21
For we take thought beforehand and aim to be honest and absolutely above suspicion, not only in the sight of the Lord but also in the sight of men.


Presterone

  • *
  • 94
    • Galant VR-4
    • 1990
    • Head: 1G (large ports)
    • Motor: 4G63 2.0L
    • Turbo: FP 16G
Re: ecu repair (not just caps)
« Reply #7 on: February 03, 2015, 03:45:07 PM »
Sounds good man, my PayPal is [email protected] if you wanna request it or whatever.

 Im in Maine but the ecu isn't heavy so it shouldn't be bad. If you can figure out what it is that's failed and decide if it can be repaired would you take a crack at repairing it? or help me find someone that will? I have used this rx4speed guy and he has good rates did a good job socketing it but since I have another car running software that you created, and this one will be soon as well, I trust your work.

Re: ecu repair (not just caps)
« Reply #8 on: February 03, 2015, 08:39:37 PM »
Well I fixed and socketed the ECU I'm using on the JimStim right now, complements of redrum97.

Had 1 bad trace I couldn't figure out, totally exploded on the backside, found it tracing the traces.


It would be easier to diagnose here over the internet, since you'll be able to do what I would just do in person.

You can check the jimstim wiki for pinouts, but here's a basic synopsis:
Quote
Next most important part is understanding how the ECU powers up. The DSM ECU is a self powering ECU, so once pin 110 goes high, it pulls pin 63 down, and that should trigger the MPI relay to apply power to Pins 102 and 107. At that point the CEL should come on for 5 seconds, turn off, and you have a running ECU.

I would map out pin 63 and pin 110.

Check this picture out


Check the MPI pinouts with your voltage tester in diode check, to see if it has any connectivity, if it doesn't you can make a new trace with just soldering a jumper wire from end to end.

Quote
The ECU controls both sides of the MPI relay. On the power side IC110
pulls the coil low (ECU pin 63, IC110 pin 4) when it sees 12v from the
ignition switch on IG1 (ECU pin 110, IC110 pin 1). The same circuit
handles the time delay before turning the relay off on after you turn
the ignition off.

The other side of the MPI relay is fuel pump related and is controlled
by IC109 (ECU pin 63 IC109 pin 7)

If those 2 traces come out fine, on IC110 I would think that most likely the IC is bad, or the SOT-223 is bad.
AMP 2 Corinthians 8:21
For we take thought beforehand and aim to be honest and absolutely above suspicion, not only in the sight of the Lord but also in the sight of men.


Presterone

  • *
  • 94
    • Galant VR-4
    • 1990
    • Head: 1G (large ports)
    • Motor: 4G63 2.0L
    • Turbo: FP 16G
Re: ecu repair (not just caps)
« Reply #9 on: February 04, 2015, 03:06:26 PM »
thanks man ill look into this asap.