Schematic for F90TLR

[jackmanjls]

I have F90TLR, 2006 90hp.

My manual doesn't give a good explanation of what's going on with the CDI ignition.

Is there a schematic or some material that I could refer to before I start to troubleshoot my problem?

I'm also looking at resistance and DVA specs for the different components.

[boscoe99]

An F90TLR does not use a CDI system. It uses an engine control unit with a transistorized ignition system.

The Yamaha service manual provides a complete wiring diagram/schematic in the back of the book. Also Resistance values and voltage specifications are usually provided in two places. In chapter 2 (specifications) and chapter 8 (Electrical Systems).

Yamaha service manuals have very little theory of operation. They are written for trained mechanics. Written poorly I might add.

https://www.vansoutboardparts.com/se...a-f75-f90/file

[jackmanjls]

B99...from your experience does the YDS help in the analysis with verifying that the ignition system works as expected? Is there a better way to verify correct opertion/parameters?

[99yam40]

the service manual should have procedures/steps for testing the ignition system along with what test equipment is needed to do the testing.

[boscoe99]

YDIS is a weak diagnostic system IMO. Particularly when compared to a modern automobile system. It can be helpful but has limited value.

Are you still suffering from a rough idle problem?

Did you test the orange wires for 5 volts?

Did you inspect the idle control valve wires for integrity?

[jackmanjls]

B99..yes and yes. The orange wire was at or about 5v. As far as the ISC I used YDS and thought that was the issue. Ordered the part, $200+, installed and it didn't work. I put the YDS on after the ISC install and the static and dynamic tests work as expected. I of the opinion that I didn't need the ISC.

I put the boat on the trailor and have in the driveway. I started right from ground zero, that is, 3 things are required for motor to run...air, fuel and electrical.

I've completely went through the fuel portion, ie, from input water separator filter to injectors. I completely disassembled the VST and on the bench I had 70psi and holding. Every filter has been looked at, all hoses inspected. Injectors have been cleaned and new filter and O-rings installed. The low pressure fuel pump was disassembled and inspected, it was fine. New plugs installed. My conclusion is that the fuel portion is not the problem.

Now I'm onto the electrical. I'm in the process of investigating what I need to know to tackle the electrical analysis. My multimeter and DVA adapter are all fired up and ready to make the first move.

I'm not going to make the same mistake that I made with the ISC.

That's it in a nutshell.

[panasonic]

Keep at it...you will figure it out. It is a learning experience. When frustrated walk away from it and have a smoke, coffee or drink....whatever is needed...lol

[rodbolt17]

it is a dirt simple open loop speed density EFI.
suck.
squeeze.
bang.
blow.
been that way for over 130 years.
what part are you missing?
YDS simply shows you what the control unit sees.
in range failures wont toss a code.
the tech has to use the tool twixt the ear lobes.

[fairdeal]

in your other thread, Rodbolt had this to say about your YDS printout:

your idle TPS value is not right.
your idle intake pressure is not right.
I don't know whet the baro pressure was that day in your area so I cant say on that.
monitor baro and intake at key on engine off. both should match your local weather channel.

[jackmanjls]

RB17...from a previous thread I fixed/verified the issues that I had with my previous YDS printout.

[jackmanjls]

I went back and did a continuity and inspection of the wires from ISC and TPS back to the ECU. There were no problems found.

In a previous thread RB17 suggested the 5v reference to the TPS could the an issue. I stuck a pin in the orange wire at the TPS, this is the 5v ref. I turned on the ignition (not the starting position) and read a static 5v. I then started the motor and the ref immediately went down to 3v. I let the motor run for 1min and the ref was still at 3v. I turned the motor off and came back 15, 30 and 45 mins later and the ref was at 2.85v.

Since this is a 5v ref I believe it should be a constant 5v. I would think the ECU basis it's decisions on a 5v ref and going to 3v would not be correct.

Are there other sensors that could control this, ie, water temp, oil pressure, etc.

Any ideas on what might be the issue?

[rodbolt17]

ideas?
something is loading down the 5V circuit.
many sensors are on that 5v ref.
I have seen water pressure sensors and speed sensors do it.
the 5V is generated from the ECU and fed all over. look for a load or a corroded connection.

[jackmanjls]

RB17..the 5vref is an orange wire on the TPS. If I use the wiring diagram and follow the orange wire back to the connector (L) I notice that there are 2 other orange wires. One is the input from the ECU and the 2 others go to Sensor Assambly and the TPS.

Is the Sensor Assembly a generic depiction that covers all the sensors or just a few? How can I find out what sensors are in the Sensor Assembly?

[rodbolt17]

if it is under the hood and orange it is a 5v wire.
sometimes the sensors are daisey chaned so one sensor can fail or have an issue and drop the 5v on another sensor.
almost all 3 wire sensors,some such as speed or water pressure may or may not be installed but wire damage to the socket can pull a circuit down.
DO NOT stick wires with pins, NEVER EVER.
certain failure will result.
use a paper clip and slip it up the wire at the connector.

[boscoe99]

I went back and did a continuity and inspection of the wires from ISC and TPS back to the ECU. There were no problems found.

In a previous thread RB17 suggested the 5v reference to the TPS could the an issue. I stuck a pin in the orange wire at the TPS, this is the 5v ref. I turned on the ignition (not the starting position) and read a static 5v. I then started the motor and the ref immediately went down to 3v. I let the motor run for 1min and the ref was still at 3v. I turned the motor off and came back 15, 30 and 45 mins later and the ref was at 2.85v.

Since this is a 5v ref I believe it should be a constant 5v. I would think the ECU basis it's decisions on a 5v ref and going to 3v would not be correct.

Are there other sensors that could control this, ie, water temp, oil pressure, etc.

Any ideas on what might be the issue?

You have now learned a valuable lesson. Almost always test a wire for voltage with an electrical load on the wire. To do otherwise is a waste of time and can result in the purchase of unneeded components.