GYTR tuner can't communicate with the ECU ?

Here is a list of the schematic component items from my 2012 manual.

1 AC Magneto

2 Rectifier/ regulator

3 (Joint ?)Connector

4 Battery

5 Main fuse

6 Starter relay

7 Starter motor

8 Starter relay diode

9 Headlight relay

10 Connector

11 Connector

12 Connector

13

14 Starting circuit cut off relay

15 Start switch

16 Main switch

17 Joint connector

18 Clutch switch

19 Diode

20 Fuel pump

21

22 ECU

23 Ignition coil

24 Spark plug

25 Injector

26 Neutral switch

27 Throttle position sensor

28 Intake air pressure sensor

29 Lean angle sensor

30 Coolant temp sensor

31 Intake air temp sensor

32 Joint connector

33 Engine stop switch

34 Speed sensor

35 Multi function display

36 Fuel sender

37 Resistor <- signaling system diagram

38

39

40 Joint connector

41 Joint connector

42 Connector

43 Headlight

44 Taillight

Item #13 is on the schematic, but not listed as a component.

I cannot find items #38 or #39 on the schematic.

The list is handy because it allows one to identify a component without having to turn to a different section when the component isn't listed in that section.

I think joint connector, item #32 powers the ECM via one of the wires labeled color "L". The L colored wire also feeds items 27, 28 and 29, which are the throttle position, air intake pressure and lean angle sensors.

In my schematic the 3rd L colored wire from the left goes up and then into the ECU. On the YZ450F, the red wire from the programmer connector goes straight to the other red wires and into the ECU.

I think joint connector, item #32 powers the ECM via one of the wires labeled color "L". The L colored wire also feeds items 27, 28 and 29, which are the throttle position, air intake pressure and lean angle sensors.

In my schematic the 3rd L colored wire from the left goes up and then into the ECU. On the YZ450F, the red wire from the programmer connector goes straight to the other red wires and into the ECU.

Does the L color wire go anywhere else? And did you see the 6+ volts at the ECU?

Does the L color wire go anywhere else?

Yes, it supplies power to several sensors, as mentioned above.

And did you see the 6+ volts at the ECU?

I haven't figured out which color is "L" and I haven't figured out which wire on the ECU is power.

L is blue.  I think the ECU gets switched power from the brown wire.

I found 38 and 39. 39 appears to be a diode. 38 looks like a classic 3 terminal voltage regulator. They are in series. The output wire color is Lr and it goes to the ECU. As does a brown wire.

Item 13 must be the condensor. Apparently its not needed for the bike to run as its not listed in any of the diagrams.

Edited by MidlifeCrisisGuy

There appears to be a diode, #39 between the brown ECU wire and the red wire for the #38 tuner connector.  I think the voltage from the tuner is blocked from reaching the ECU by that diode.  You could try bypassing it but I'd hate for something to blow up if I'm wrong.  Edit: 38 says coupler for connecting optional part.  Is that for the tuner?

Edited by funt

L is blue.  I think the ECU gets switched power from the brown wire.

You might be right... Red goes into the Main switch (item 16) through joint connector 17 through connector 12 through connector 11 through connector 10 to the diode/voltage regulator pair (39 and 38) and on to the ECU.

I'm off to test it.

Edit: 38 says coupler for connecting optional part.  Is that for the tuner?

Where does it say that ?

If it is a connector, on my diagram they just draw it as a block. And there is no pin out like all the other connectors. Edit: actually there is one. And the colors match the connector colors.

What year is your owners manual ?

Makes perfect sense that 38 is the connector though. The color I was describing as lavender is probably Lg.

So why does the WR have a diode and the YZ does not ? What would be wrong with the programmer voltage (6.8 volts) flowing back on the brown wire ?

Why didn't they put the diode upstream of both the ECU and the programmer supply ? I think its to prevent the programmer from trying to power things like the coil in the starting circuit cut off relay (item #14.)

My bike doesn't have any of those things.

I think the difference between red and brown is that brown is switched whereas red is hot always. The YZ doesn't have a switch.

Edited by MidlifeCrisisGuy

I've got a 2012 manual.  There's 2 wiring diagrams in the back that fold out.  One in black and white and one with colors.  The page before that has the numbers that says what everything is and the color code.  I think the switched power comes out of the #10 connector and then it branches off to the ECU and the #39 diode.  I think the Lg, light green that goes between #38 and the ECU is what sends the signal for reprogramming.  Is #38 where the power tuner hooks up?  Maybe that's where the dealer's fuel injection tool hooks up.  Could be both.  They don't talk about any of this stuff in the manual.

Edited by funt

I've got a 2012 manual.  There's 2 wiring diagrams in the back that fold out.  One in black and white and one with colors.

Holy crap that makes things easier !!!!! I owe you one for that ! I've been looking at the little gray and white diagrams in the troubleshooting area. I've almost gone blind !!!!

 

The page before that has the numbers that says what everything is and the color code.  I think the switched power comes out of the #10 connector and then it branches off to the ECU and the #39 diode.  I think the Lg, light green that goes between #38 and the ECU is what sends the signal for reprogramming.  Is #38 where the power tuner hooks up?  Maybe that's where the dealer's fuel injection tool hooks up.  Could be both.

Its both.

 

They don't talk about any of this stuff in the manual.

Nor do the dealers know anything about it !

Edited by MidlifeCrisisGuy

Lookie what I found !

20131007_202037.jpg

From top to bottom is the ECU connector, then the programming connector and at the bottom is the diode in question. Off to the right is the connector for the tail light.

Here is a closer view of the diode.

20131007_202143.jpg

As you can see, I relocated the ECU and the condensor to under the seat on top of the air box. They fit nicely. No harness modifications were needed to do this. Oh yeah... I also had to cut out the battery tray. That is the only non reversible change I have made to the bike. I have a TIG welder, so I could always put it back in if I needed to.

The programming connector resides in its normal location when I am not troubleshooting stuff.

I'm going to jumper out the diode and test that the programmer voltage doesn't drop when its connected.

Edited by MidlifeCrisisGuy

I jumpered it. The ECU voltage stays up at 6.8 volts. The programmer voltage stays up too. (Should be the same and they are). But I still get the error code when I try to program it.

I bet the ECU needs 12 volts, maybe the programmer too. After all, the brown wire will feed power into the programmer via the diode and if the programmer was self powered, it wouldn't need a power connection.

At least now I have a convenient place to hook power into.

However, one thing bothers me... the YZ doesn't need to be running when its programmed. The programmer does it all.

Maybe I need NiMH batteries ? On both bikes the programmer must charge the condensor.

Edited by MidlifeCrisisGuy

I'm an idiot ! I forgot to connect the ECU !

Now when I connect the ECU, when I try to turn on the programmer the fuel pump runs ! And the programmer won't turn on fully.

So either NiMH batteries have enough juice to run the fuel pump or I need to isolate programmer power from going to the fuel pump and maybe other things.

But judging from the YZ450F schematic, the programmer must power the fuel pump there too because the red wire from the programmer connects directly to the fuel pump supply. Though the low side of the fuel pump appears to be controlled by the YZ ECU. So maybe the YZ ECU turns off the fuel pump if it senses the programmer is connected ? But how does it know if the programmer is connecting to monitor, in which case it needs the fuel pump or sending mode, in which case it doesn't need the fuel pump.

Edited by MidlifeCrisisGuy

Does the fuel pump turn off when pressure is reached or does it keep running ?

The WR and the YZ have the same wiring with respect to the fuel pump.

Edited by MidlifeCrisisGuy

I found this in the YZ section.  Might be worth a try.

I was having the same problem with my tuner as well but found a work around. Plug the tuner into the bike, start bike (automatically powers up the tuner), do any monitoring you want with bike running (idle, temp etc.), turn bike off (tuner will stay on), transfer maps etc as you normally would with tuner on and bike off, power down tuner and disconnect.

I went out and checked the plug on the bike. If I turn on the power switch the plug gets 12 volts. So you don't have a battery so no 12 volts.

Edited by vlxjim

I found this in the YZ section.  Might be worth a try.

I'll give it a try and report back.

I went out and checked the plug on the bike. If I turn on the power switch the plug get 12 volts. So you don't have a battery so no 12 volts.

a) Thanks for doing so. Appreciated.

B) A YZ450F isn't going to have 12V when its turned off either.

The ECU probably only needs 5-6 volts to run from. But the fuel pump draw is probably beyond what the el cheapo alkaline batteries that I have in mine can provide. I didn't realize it was supposed to be powered by NiMHs until this morning.

I think the idea of running the bike and then turning it off is a good one. Running it will charge the condensor and negate the fuel pump trying to start up from a dead start.

Did you get it to work?

Did you get it to work?

Haven't had a chance to try. Its been a busy week.

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