Tin Shed
Newbie
I have a 07 Apex with 4,300 miles. All of a sudden I have no spark at any of the 4 cylinders. I have no codes that flash on the display and no check engine light. I have soldered every ground block so I assume that is the issue. I thought it was a bad crank sensor so I replaced the stator and cranks sensor with new Yamaha parts. I have continuity from the ecu to all 4 coils. I have power at al 4 coils. Am I missing something or do I have a bad ECU? Cranks over normal with a brand new battery and I can see fuel spraying in the throttle bodies from the injectors.
Thanks in advance Tim
Thanks in advance Tim
Do you have continuity from the pickup coil to the ECU?
Tin Shed
Newbie
Pickup coil? do you mean the Crank sensor that is part of the stator? Wiring checks out from "black box" coil to ecm. power and ground are good at the coil.
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Yes, the coil (or inductor) sitting next to the stator is what tells the ECU where the crank is in time which drives when to fire the coils. Wiring checks out is good, you also need to check for resistance to make sure the coil is good. Assuming the coil is good, you should be getting some kind of firing signal from the ECU to the coils themselves. The wiring from the pickup can also be backwards and that will probably keep it from firing. Do you have the service manual? That will give you the wiring diagram.
Tin Shed
Newbie
I have the service manual. The resistance of the crank sensor is 424 ohms at 60 air temp, exactly the same as the one I removed from the sled. Wiring from the sensor to the ecm all checks out. I even did a voltage drop on the wiring. I tried switching the 2 wires at the connector from the crank sensor. I checked all 4 ground wires from the coils to the ecm and all are ok. I have over 12 volts at all 4 coils when cranking. I am suspect of the ECM not grounding each of the coils. Largest concern I have is I gave one of the coils a ground manually with a wire expecting a nice blue arc and it was very dim....
To check if the ECU is firing the plug attach one end of the voltmeter to the ign side and the other end to the ground or ECU side of the coil connector. Crank the motor over. You should get changing voltage as it cranks. This will tell you if the ECU is grounding the coil when it needs to.
coil resistance is fine and since it was the same as the other I agree, its probably the ECU grounding the coil.
Not a dumb question but do you have the kill switch on.
Tin Shed
Newbie
It will not crank over with the kill switch on. I checked and cleaned the ignition switch connector and kill switch connector When craning with volt meter or test light there is no change on the ground side of the coil. I also tested the crank sensor. Should that flash a test light when your cranking on the one side? the other wire is a ground all of the time?.
Hey Steiner
, whats the best way to check for faulty ground? Both my units won't start or even give a sputter. I occasionally see the injectors spraying fuel but not consistently. I've replaced plugs. Are the ignition coils / ECU grounded at the same place as the fuel injectors? both sleds at the same time and both have been sitting a long time. I've replaced the fuel in the one sled last winter already but that made no difference. Even sprayed fresh fuel into the intake and not even a sputter. So I'm thinkin corroded ground or something. Any ideas?
There will be no ground blocks for these wires as they go directly to the ECU which is controlling the ground pulses to the coils.Hey Steiner
Have you checked the stator?
no i haven't. Didn't even consider that as both units are doing the same thing. i supposed they could both go at the same time or each sled have different issues. whats the easiest way to test the stator?
