Schematic for F90TLR

[jackmanjls]

===============EDIT ALERT ================
11-6-2017 ==> I took another look at the 5vref today and it isn't a problem. Previously the placement of the meter probe ground was not good ground.
I went directly to the ground from the battery and found that the 5vref was solid as a rock.
========================================

I did a search on the internet for "clear error codes for yamaha outboard" and didn't have much luck so they weren't cleared.

I put the YDS back on the motor and ran some tests.

The Diagnostic Record displayed the previous errors (37,18,23,28,29) that I tried to clear but also gave me a msg:
1. Check no air leaking in intake passage

Any ideas on what this might be?

Then I ran the Active Test: ISC valve opening test for 5 mins and monitored the 5vref. The ref varied from about 3.20v to 2.21v. This is a large fluctuation for a reference v.

Also ran the Active Test: Fully open ISV valve. This test doesn't die on accel but very close to it. There is some hesitation before the accel.

Next I focused on troubleshooting the problem with the 5vref. I disconnected the TPS, sensor assembly and CL connectors S and W while still monitoring the 5vref. The intent was to find something that loaded down the 5vref. The voltmeter didn't change it remained at ~3v. So, nothing seems to be loading the 5vref.

One additional observation. Yesterday, I reported that when I monitored the 5vref that it was 5v BEFORE I initially turned the key on. Today, I go out and BEFORE the initial key turn and the value is 3.3v.

At this point I'm thinking that the ECU 5vref appears to be a problem.

Any ideas?

=== EDIT
I am going to try and disconnect the orange wire at connector L pin13. This will completely isolate the ECU 5vref. If I get the 5v, from the ECU, then I'll look deeper if not then that tells me the 5vref at the ECU is not referencing properly,ie, it's hosed.

==== EDIT
Connector L buses together the 5vref to other sensors. It looks like the 5vref from the ECU can't be isolated. When I turn the key on I get an audible and the ECU doesn't put out the 5vref. Bottom line is I can't isolate the 5vref from connector L.

[rodbolt17]

first clear the codes, don't really care what set 300+ hours ago. then start the motor and see what comes back. you can disconnect any sensor you wish with the engine running. it should step up the idle speed but wont hurt anything.

[fairdeal]

The purpose of measuring water pressure is obvious. What is this speed measurement?

[pstephens46]

as Boscoe has explained, your SM does/may not show the Command Link wiring - but its there.

Here are the "S" and "W" connectors as they come from the factory - not connected to a sensor:

The purpose of measuring water pressure is obvious. What is this speed measurement? Speed of water flow through block? 2:44am and I can't sleep....

[fairdeal]

as Boscoe has explained, your SM does/may not show the Command Link wiring - but its there.

Here are the "S" and "W" connectors as they come from the factory - not connected to a sensor:

[jackmanjls]

I have several times been disappointed in finding the Command Link wiring reflected in a Yamaha Service manual...

I will check tomorrow in daylight the wire colors on my 2006 F90 "S" and "W" connectors.

But you can easily see if either of yours is connected to a sensor, or just parked/plugged.
If one or the other is, just disconnect it - no need to disconnect the CL itself.

I check and recheck the wiring diagram and I don't have a "W" connector but I do have an "S".

The "S" connector is part of the lower ECU connector, pins 19 - 52. Pin 20 is the orange wire but that goes up to connector L on pin 13.

In addition just below the wiring diagram is an index of references for the wiring diagram and in that list there's nothing about speed or water pressure sensor.

Could it be that the CL is an add on and not included in the wiring diagram?

[boscoe99]

[fairdeal]

Unless I'm looking at the wrong wiring diagram there are only 3 orange wires. One is the output from ECU and the other 2 go to the Sensor Assembly and TPS.

So far the manual has been fairly accurate.

Interesting thought about the Command Link. I have the square version. Is there an orange 5v ref of is it some other color?

As a first step...is there anything you can suggest where I can completely disconnect the command link to see if that is the issue?

I have several times been disappointed in finding the Command Link wiring reflected in a Yamaha Service manual...

I will check tomorrow in daylight the wire colors on my 2006 F90 "S" and "W" connectors.

But you can easily see if either of yours is connected to a sensor, or just parked/plugged.
If one or the other is, just disconnect it - no need to disconnect the CL itself.

[boscoe99]

Fairdeal...your comment,

Is there a Command Link water pressure/speed sensor installed? poster child for shorted reference voltage....

No water pressure or speed sensor that I know of.

================================================== ==========================================

Unless I'm looking at the wrong wiring diagram there are only 3 orange wires. One is the output from ECU and the other 2 go to the Sensor Assembly and TPS.

So far the manual has been fairly accurate.

Interesting thought about the Command Link. I have the square version. Is there an orange 5v ref of is it some other color?

As a first step...is there anything you can suggest where I can completely disconnect the command link to see if that is the issue?

The manual is hosed. Typical Yamaha garbage. But it is all that is available.

Beginning in 2006 Yamaha four stroke EFI models were provided with the ability for two optional sensors to be installed. Sensors are one and the same but used in two locations for different purposes. One is referred to as a Speed sensor and the other is referred to as a Water pressure sensor.

Early sensors were known to have a problem whereby water would get from the wet side to the electrical dry side. Water might migrate up a wire all the way to the ECU or to other places. Check your motor to see if the optional sensors have been installed. Either one or both. The connector to the water pressure sensor will be marked with a W. The connector to the speed sensor will be marked with a S.

The SM does not depict the wiring for these sensors. Each will be connected with a three wire connector. One of the wires is Orange. For the 5 volt supply.

[fairdeal]

TPS sensor or not?
Part of the 5vt daisy chain or not?

.

My apologies - and thank you for pointing out my error.

I meant to write that the ISC valve has no sensor and can not effect the 5v.

Of course the TPS is part of the 5V system

[pstephens46]

"unless I am mistaken" there are only four possible "sensors" (4 "orange wire users") on that engine:
- TPS
- MAP/temp (a dual sensor)
- Command Link "S" (speed)
- Command Link "W" (water pressure)

The TPS has no sensor/no possible effect on the reference voltage.

Is there a Command Link water pressure/speed sensor installed? poster child for shorted reference voltage....

TPS sensor or not?
Part of the 5vt daisy chain or not?

I'm going to go play with my Seastar.

[boscoe99]

I'm confused.

Yes, less than normal confusion or more than normal confusion?

[jackmanjls]

Fairdeal...your comment,

Is there a Command Link water pressure/speed sensor installed? poster child for shorted reference voltage....

No water pressure or speed sensor that I know of.

================================================== ==========================================

Unless I'm looking at the wrong wiring diagram there are only 3 orange wires. One is the output from ECU and the other 2 go to the Sensor Assembly and TPS.

So far the manual has been fairly accurate.

Interesting thought about the Command Link. I have the square version. Is there an orange 5v ref of is it some other color?

As a first step...is there anything you can suggest where I can completely disconnect the command link to see if that is the issue?

[99yam40]

I'm confused.

is that odd or different than normal?

[pstephens46]

I'm confused.