2007 Yam f115 no start, won’t connect to YDS

[Mark426]

Hi. Long time reader, first time poster. I've been searching and havent found anything that resolves my issue.

Engine is fuel injected f115/4 stroke.

It is on a stand. Was a spare for a long time. Previous owner said she was running but sat for a while and “could use a tune up.”

When I first got it, I was able to connect YDS - it has about 500 hours.

I finally got a harness to try to start it on the stand. On key on, I get fuel pump run and good pressure at the rail (55psi or so IIRC).

It cranks but won’t fire. I tried jumping kill switch and neutral start switch to no avail. Tried a different key switch to no avail. Charged battery, no difference.

It does crank faster with throttle, but does not fire.

I’m thinking coil or stator. From what I understand, any sensor failures will cause a fast idle, but won’t cause a stall.

I checked spark with a checker and directly against the block. It seems a little weak/intermittent, but I wasn’t convinced either way. However, I can’t get YDS to connect now, on the same system.

Fuses all seem fine, every connector I’ve checked had been fine.

If I unplug the ECU, the fuel pump stops running.

Is there a way to check the ecu beyond that? Should I be looking into coil pack or stator next?

Thanks in advance.

 

[rejesterd]

I would spray some starting fluid to see if it will fire when you do that. If it does, there's more to your issue than just spark. If spraying the starting fluid doesn't make any difference, then you will need to test the ECM and pulser coil output peak voltage (according the service manual). That's the test Yamaha provides for these components.

Sensor failures can cause stalling though. There's no telling what the ECM will do if it gets feedback from a bad sensor. There's no built-in protection to the keep the engine running if a sensor fails.

 

[Mark426]

I also pulled compression as part of my general assessment of this engine. Solid numbers and even on all cylinders.

I’ll try some starting fluid and see what happens.

I know that if I unplug either ECM connector with the key on, the fuel pump stops running.

 

[rejesterd]

Yeah, I would expect the pump to stop working if the ECM is unplugged, because the pump is grounded through the ECM.

So if the starting fluid test shows no change, then test the coils. If they're good, then test the ECM and the pulser coil.