1990 yamaha 200 tough question

[wizardofog]

I hope someone can help me with this question (Yamaha didn't give me the info). Anyway, I have a Yamaha 200ETXD and it has the Hitachi CU2681C control module on it which I think is Yamaha's part number 61H-85540-00-00 and I need a logic schematic for it. More specifically I need to know what inputs need to be in what state to turn on the output for the pump in the oil tank to send oil to the engine tank.

My assumption is that at least the floats in the main oil tank need to be activated (raised with oil) and at least the floats in the small "on engine" tank are not activated (low oil condition). Any help on whether these floats are "normally open" or "normally closed" would help too... I assume they are normally open and closed when they are raised by the oil level. I will check them soon anyway.

I am also assuming that the trim angle input to the control module may play a part in whether the oil pump output turns on too. And I have no idea what else may effect it which is what I need the logic ha ha.

To simplify this, if someone has the knowledge they could share on this control to be able to say something similar to what I have listed below would be greatly appreciated:

IF: (12 volts on wires X, Y, Z), and (ground on wires 1, 2, 3) and (continuity on wires A, B) and (continuity on wires C,D) and (approximately 15 ohms of resistance between wires E,F or trim inputs)

THEN: Ground will be applied to the oil pump output.


Please forgive me is there is a thread on this somewhere already, but I didn't see one. If there is please send me the link to it.

Thanks in advance for your help on this matter, it has been an aggravating one for sure.

Thanks,
Van

[wizardofog]

I forgot to add that I do have the wiring schematic for the motor but it does not give the logic for the module.

[boscoe99]

Main (engine mounted) oil tank sensor has three switches in it. Top switch closes (float up) tells the control module to stop the flow of oil (tank is full). Middle switch closing (float going down to middle of tank) tells the module to start the flow of oil. Bottom switch closing (float almost to bottom) tells the module to sound the warning horn and to put the motor into RPM reduction mode.

However - If and when the middle switch closes the module is looking to see if the remote tank has an adequate amount of oil in it. It is looking for a switch in the remote tank sensor to be closed. If the oil tank is low on oil (or the system thinks that it is because of defective wiring/trim sensor) then the automatic system won't function.

12 volt power must be provided to the remote tank pump. A ground reference is provided to the pump by the control module. If there is no power or if the ground can't get to the pump (bad wiring, bad connections, bad control module, etc.) then the auto transfer system won't work.

Here is a diagram from an HPDI model that should give a better idea of what does what, and when.

[wizardofog]

Ok. Thank you very much for the info. I can check all of that.

Can you tell me if the module uses the trim potentiometer resistance as an input in determining whether to apply the ground to the oil pump (i know you mentioned the trim) and if so, what should the resistance be?

Thanks again.

[rodbolt17]

yes,the 1990 V6 2.6L uses the trim signal to inhibit oil transfer if trimmed beyond the trim angle.
a simple radio shack resistor will work to signal trim angle.
would be much easier if you state what is wrong.

its a dirt stupidly simple system.