Tohatsu ECU replacement

[w2much]

I have a Tohatsu 90 nHP model # MD90C2 3FW , Serial #034700AX. I am told the ECU needs to be replaced. When the ECU is replaced does it need to be (not sure of the term here) flashed or set to work with my injectors? Or can I expect it to be plug and play ? I am obviously not familiar with ECU's or injectors. Any help is appreciated.

 

[pvanv]

Just plug it in and reset the TPS initial setting. Why does it need to be replaced?

 

[w2much]

Just plug it in and reset the TPS initial setting. Why does it need to be replaced?

We can not get the number 2 cylinder to fire. On the #2 coil there is no input. The coils have been switched but still no juice. I was not there when this was done but told the wire going to the #2 coil has no power at all. Any suggestions. Could this be stuck in safe mode ? Or something similar ?Thank you for your reply. I am rerally in a spot here.

 

[MattFL]

Before replacing the ECU, put an ohm meter on the wire between the ECU and the coil and make sure the wire harness is still good. It could be a bad ECU, or it could just be a bad wire.

 

[w2much]

Just a shot in the dark here but lets say the wire is good and there is no juice to the coil does that indicate the ECU is definitly bad ?

 

[pvanv]

Check for signal right at the ECU first, before condemning the unit.

 

[w2much]

Thank you, good thought. The motor is not here but when I can get to it I will and post what happens next

 

[w2much]

The wire checked at the ecu body also no signal. Dang pricey part. Are there any compatible motors or ecu's which may work here ?

 

[pvanv]

You need the OEM ECU.

 

[w2much]

That's what I figured. Being as it is quite pricey I thought there could be a compatible alternative. I will continue my search for a. reasonably priced used one. Considering the price Is the motor worth the repair cost ?

 

[pvanv]

Well, it's over 10 grand for a new 90 hp motor...

 

[w2much]

I found an ECM for750. I hope it goes well. Thank you for your reply.

 

[w2much]

All cylinders firing with new ECM. Took some pictures because when I spend money I want to remember why. This dripping goop is also on the crankcase. It did not come from above . I checked. I gather something heated up but good and blew out here. Any thoughts ?

 

[pvanv]

Apparently your old ECU had a catastrophic failure.

 

[MattFL]

Either air bubbles in the potting material when they potted it, or something buried in the potting got really hot. If that's the old one, it's going to be a lot of work but you can chip away the potting to see what you find.

 

[w2much]

Yup. It was catastrophic alright. Quite painful . I have seen ECUs in worse visual shape. It kills me that this one has such a small footprint of a burn. 2300 dollars and the issue may be 1 or 2 or a few more low dollar cost capacitors, diodes or whatever.
Time to put it behind as now I need to clear the codes and set the new ECU up. Problem here is I don’t know how to read the codes. I have a Tohatsu manual which explains how to clear codes but where do I find out how to actually read the codes. Is it in the owners manual, which is downloadable ?

 

[w2much]

As usualthe info is in the manual I just got anxious and missed it. Now I know it is there it will take some time to really understand what it is saying. i realize I need to reset the ECU and the TPS. So here is my new issue. As part of the procedure, wouldnt you know , part one,"Set the key switch to the ON position. Disconnect the stop lock switch within 1 second after the beep stops sounding" Problem is I have no beeping. Can anyone help out here ? I have the tach only hooked up, not the voltmeter or trim gauge.

 

[pvanv]

RC boxes have the beeper in the RC box. Are your wires not connected?

 

[w2much]

The wires were connected. After testing the buzzer I found it unresponsive to 12 volts. I ordered a new one. For now I am running the horn wires external to the remote and hooked up to an old buzzer the old buzzard had in the shed. Today I shall recheck and reset the ECU. I appreciate your replies. Thank you.