2006/07 Arctic Cat 700efi No spark at all! No codes!

[RepairmanJake86]

Hey fellas, I've been referring to this forum a bunch over the years , but finally needed to create an account for some help,, so this is my first post. I'm working on a friend's 06 Arctic Cat 700efi that has no spark whatsoever and am kinda at a loss. To begin with, he had tried to fix it himself so he had replaced alot already...I know, I know lol. This is what has been done; New plug twice, new coil twice with new one ohming out great, new stator, new rectifier,  and new starter solenoid. 
.    The biggest frustration is that I've got no codes. ECU shows that I'm in neutral and my brake safety switch works. I also show 12.5v at the tilt sensor pin on ecu which I assume is correct and then if u flip, then u lose voltage. Am I right, or no? Only other things I can think to do is replace Crank position sensor, get a peak voltage meter and read my peak voltages, or replace ecm which obviously is last resort.

I also verified the pulse coil. Thank you in advance
 

[Mech]

On cars when there's no trouble codes they recommend checking all the power feeds and earths, especially to the ECU.

[RepairmanJake86]

I've got no signal from the ecu to the spark coil. I did disconnect the neg cable from the battery, and put my test light in series with it. It then lit up when I touched ground. So I put my power probe on it and I've got battery voltage to ground. I start pulling fuses and it's in the fuel circuit. 

 

That's where I'm at so far 

[Mech]

Ok, so in the list of trouble codes, is there one for an open circuit in the ignition feed wire ?

Perhaps there is no code for that fault.. If there is a code for that fault, then I'd still be expecting a bad earth or power to the ecu.. They often have several power and earths to a ECU. And all the powers and earths going into the ECU  are for separate circuits, so you need to confirm they are all good.

It's also possible that the ECU acts as a CDI and only sends a pulse of power to the coil when a spark is needed. I'm not familiar with those machines.

Other than that.. there's a break or an earth in the wire from the ECU to the coil.

[Mech]

The fuel circuit might have power all the time and then the ECU earths it when they want the pump or injectors to go.. If it's fuel injected. That's fairly common.

The manual should describe how things operate.. Do you have a manual ? And what sort of motor does this have ? Suzuki by any chance ?

[RepairmanJake86]

7 minutes ago, Mech said:

The fuel circuit might have power all the time and then the ECU earths it when they want the pump or injectors to go.. If it's fuel injected. That's fairly common.

The manual should describe how things operate.. Do you have a manual ? And what sort of motor does this have ? Suzuki by any chance ?

Yes it's suzuki. I have a service manual for the Cat but not the engine itself. I don't recall seeing anything about fuel circuit having constant power but ill look again. Appreciate the response 

19 minutes ago, Mech said:

Ok, so in the list of trouble codes, is there one for an open circuit in the ignition feed wire ?

Perhaps there is no code for that fault.. If there is a code for that fault, then I'd still be expecting a bad earth or power to the ecu.. They often have several power and earths to a ECU. And all the powers and earths going into the ECU  are for separate circuits, so you need to confirm they are all good.

It's also possible that the ECU acts as a CDI and only sends a pulse of power to the coil when a spark is needed. I'm not familiar with those machines.

Other than that.. there's a break or an earth in the wire from the ECU to the coil.

Appreciate the response,  but the wire from the ecu to the coil is good..I am going to untape the harness and look for breaks though 

[Mech]

The fuel and the ignition could both have power to them and then be controlled by the ECU earthing them.

Wires almost never break inside the loom. They break at/where they go into the terminals where they connect to things, or they wear through and short where they rub on the frame. If there is a break in a wire, it's going to be inside that wire's insulation and you probably won't find it by looking.

You need a multimeter that can check ohms and use it to check the continuity of the wires from one end to the other. You really don't want to be going pulling the loom apart just for a look. I'd inspect the loom for shorts to earth, (which will be obvious by the worn through tape and insulation) and check for continuity from one end of each wire to the other.

You need to bear in mind that the power to the coil could come straight from a fuse, then be earthed inside the ECU and controlled by the ECU to fire the spark. Or it could have the same setup except with the power coming from in the ECU. Or the coil might have an earth wire(or not, it might earth internally) and be sent a short pulse of power from the ECU to make it spark. If it's the last option then there will only be a short burst of power in the coil's circuit when the motor is turning over. You really need to know or figure out which system it is so you know which wire is meant to have power, and when it's meant to have power.

If you tell me where you got the manual from I'll try and download it and see if I can figure it out with you..

 

And do you have a list of the possible trouble codes?  Is there one for the coil ?

Edited December 31, 2021 by Mech

[Mech]

Ok so I had a read up and it seems likely this thing will be similar to a canam, and most of those do feed power through a main fuse and then an ignition fuse to the coil and the ECU shorts the coil to earth and controls the spark by turning the earth on or off..

Hope that helps.

 

[Mech]

Well.. I see there's a wiring diagram for that thing in here.. And it looks like the coil does get a pulse from the ECU to fire the plug.. That feed out of the ECU's described as high voltage, which means CDI, probably about four hundred volts and a high current.. That wire could kill you so be careful.

But that will only work with  a feed into the ECU from both the fuse labeled Ign and the feed into the ECU labeled as Switched power, which comes from the kill switch.. and the right voltage in the from the tilt switch, which I see isn't battery voltage but between 0.8 and 3 volts. If the voltage going into the tilt switch is between 4 and 8 volts it thinks there's been a roll over.

And I should mention that you shouldn't use a test light to check these circuits. The test light carries to much current and can destroy the electronics. You need a digital multimeter.. Even the current through an old fashioned analogue multimeter can fry things. 

[Cookie]

My machine had corrosion on the pins in the ECU connector, even after cleaning they didn’t make good contact. You may try back pinning at the ECU plug for a signal to spark. I used a single strand of 20wire bent over in the plug to bridge the gap to the ECU pin. Fixed. Be cautious not to break or bend pins.