[WhyTheFace]

Looking for some help. My 2015 CF 500 HO ran fine. The next day I went to start it, and the fuel pump just runs.  Does not prime then shut off. The start button does nothing. Will not crank.  There is no fuel leaking out so not sure why the pump doesnt stop running.  I bought a new fuel pump relay but no change, and tested the fuel pressure and it is exactly 40psi when the pump is running.  But either way I think the engine should crank over. I checked the main fuse under the seat and is good. Battery is fully charged. Any ideas?  **Edit, not getting any error lights on the display. Thanks!

[doug80638]

Will it turn over when you jump the starter solenoid?

[WhyTheFace]

Will it turn over when you jump the starter solenoid?

Have not tried yet.  When I was unhooking the fuel pressure gauge, the plastic elbow fitting on the top of the fuel pump broke, so now I can't do anything without spraying fuel.  Looking for a new elbow fitting and waiting on a new fuel pump from Amazon.

[WhyTheFace]

Will it turn over when you jump the starter solenoid?

Unplugged the fuel pump last night and jumped the solenoid and yes it cranks fine. Got the pod loose and can't find any loose connectors or bad wires so far.  Have to get the tank off to get to the injector. Maybe tonight.

[doug80638]

OK.  Jump the S post of the solenoid and check that the starter turns. If that works, then check voltage at the signal line when trying to start. If there is no voltage, then either a break in the line, bad ignition switch, or the ECU is commanding a no start condition, which would be odd with the fuel pump energized.

If the fuel pressure won't stay, then there is a leak in the system. You haven't said  anything about fuel odor, so I assume the lines aren't leaking. So check for a leaky injector (if found, change the oil before running), the ball stop, and the sensor/switch (part of the pump?) that determines that pressure has been reached.

There have been lots of odd-ball issues over the years, so I'm very curious about what you find.

[WhyTheFace]

I had time to do some more troubleshooting before deer hunting this weekend.  Put the new fuel pump in and no change.  Runs steady when key is on.  Builds and holds pressure. Does not leak down.
Jumped solenoid and engine cranks fine.
Start button still dead, so continuity tested that at the end of the cable and start switch and kill switch work fine. Also when kill switch enganged, the EFI trouble light comes on, so it is being acknowledged by the ECU).
Checked spark while cranking the motor, and no spark. This is while the fuel pump is running.

At a loss. Beginning to think the ECU is at fault as it controls the fuel pump and the ignition system. Not sure what other inputs might cause these issues.

Any ideas welcome!

[NMKawierider]

Did you check the AUX relay(s)? And what exactly is the fuel pressure?

[doug80638]

Lots of things from a broken wire to a bad ECU can explain what you are seeing.

If you suspect the ECU and don't have access to a PDA, you might stop by the dealer and have them hook one up and see what's going on.

There are tools listed in this forum for putting together your own PDA, and there is also a phone app that works pretty well, for a fee.

[WhyTheFace]

Did you check the AUX relay(s)? And what exactly is the fuel pressure?

No, I didn't check the Aux relays yet, will do.  Fuel pressure is 40psi exactly.

@Doug80638, thanks maybe I'll look into making my own PDA.  Unfortunately my nearest dealer is over an hour away, so would be a while before I can get down there.

[WhyTheFace]

Still no progress on this.  I tested and swapped the aux relay and it was fine, no change. Did pull the injector, and it is not spraying when the fuel pump runs, so assuming the injector is ok.  I read in an automotive forum that if the crank position sensor is bad, and sending signal when it shouldn't, that can be telling the ECU to send fuel, but then I would think the injector would be spraying.  And that shouldn't kill the spark either I wouldn't think.  Anyway, will try to test the CPS and speed sensors tonight.  Really don't want to drop $400 on an ECU without knowing.   

I searched on here for instructions on reading the codes, but didn't find any clear instructions for machines that only have the 3 wire. Does anyone have a link to a thread that has been successful?

[NMKawierider]

Many CFM Engine speed sensors...aka CPS..have failed or gotten something between the sensor tip and rotor. Loss of this signal stops both the injector pulse and spark as the ECM no longer has that base line. The tach also no longer works in the dash. However, if any of that does exist while cranking..ie an injector does spray fuel or a plug does show spark, then this is not the problem. Don't know if you have or not but also test the kill switch. It kills the fuel pump and the ignition and somehow has been known to get water inside and corrode only some contacts which produces strange results...mostly non-running.   

On the pre-2018s, you can make the MIL light flash the error code by grounding one wire. I think I have that page of the manual and will post it below if I find it.

[NMKawierider]

This is the kill switch wiring:

[WhyTheFace]

Thanks NMK !  I will try testing this stuff, hopefully tonight. I have no injector spray and no spark, so sounding like possibly the CPS, or its wiring. I have tested the kill swich at the end of its cable, but I didn't know the colors or positions in the connector, but found some that were making and breaking cleanly, so assuming its working, but I'll check that again too.

[doug80638]

I would think a bad CPS signal would throw a code, but they are easily tested on the bench as well.

[NMKawierider]

I would think a bad CPS signal would throw a code, but they are easily tested on the bench as well.

Yeah..I think it should.