30-6300: main relay reassignment, and ign timing issue | AEM
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nukefission
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Last seen: 1 year 3 months ago
Joined: 09/22/2016 - 19:06
30-6300: main relay reassignment, and ign timing issue

Background: Car is a '91 DSM. Previously ran a Series 1 box which worked fine. Installed this Series 2 box and the MPI relay would not click on with key-on. The MPI relay would not put out switched power or run the fuel pumps. The MPI relay tested OK. Suspected ECU wasn't pulling the relay to ground, so removed the board and found burnt trace for Coil 5 output (pin 63 to MOSFET). Jumped the associated wire to ground with a manual switch and MPI relay worked. Measured amperage (key on, car off) at 90 mA. The car starts and runs. So the temporary workaround is to manually ground the MPI side with the switch and the fuel pump side comes on with the key. The rest of the ECU functions normally and no other board components look damaged. Bought it used and previous owner stated there was no problem with it, but that he did have to replace a bad MPI relay. I have no idea what his setup was or how much he was trying to power with Coil 5. So I don't know if that board circuit was already on its way out when I received it or if I have some wiring issues which caused it to burn up. However, I still have the v1 and it still activates the MPI relay properly when connected and keyed on, so I think my wiring is ok. Car is set up for speed density, direct fire, and is adapted for MIVEC from the EVO IX.

Questions:

  1. 30-6300 instructions state main relay circuit (pin 63, Coil 5) is dedicated. What is the amperage rating of that circuit? Is it 1.5A max like the other low side drivers? Can I reassign the main relay in software to a different switched ground output? LS2 (EGR solenoid) is the most readily available.
  2. The Ign Timing value appears to be locked at -17°. Every conceivable modifier (knock control, rev limiter, trims, flex fuel, etc.) has been checked and all of them are either turned off or zero'd out, yet still the Ign Timing value is always -17°. Could the Coil 5 issue have anything to do with that? Updated the firmware on the Series 2 box in an attempt to address the issue and it corrupted my calibration, but attached is a previous version on which the car does run. Even tried loading a virgin base map from AEM and it's still locked at -17°.
  3. Is there a barometric pressure sensor built in to the board? I tried assigning another sensor to the baro input (pin 16) but it appears to be interfering with an existing signal.
  4. Is there a correlation between Switch 1 and all of the coil outputs? Switch 1 was disabled temporarily because Coil 5 was no longer being used, but that caused all of the coils (1-4) to stop working. Re-enabled Switch 1 and they worked again.
  5. For some reason, Stat Cranking always reports ON even when the engine is running. Crank Max is set to 350 RPM.

Thanks for any input.

nukefission
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Last seen: 1 year 3 months ago
Joined: 09/22/2016 - 19:06
OK, #2 has been addressed,

OK, #2 has been addressed, and I read that there is an on-board baro sensor but that it must be enabled with a jumper on JP2, which is currently open. However I plan on using the baro volts channel for something else, so #3 no longer matters.

Really I just need to know if it is safe to reassign the main relay to a different low side driver. If I can get away with that I can stick with this ECU for a while.