Hello

sorry if im not meant to be here i cant find a website that deals with these spy f3 Chinese quads and cant find accurate wiring diagrams so im stuck right now!

So i bought this spy f3 350cc 2021 plate for £500 (UK) but it is a none runner.

The issue I have is I have no spark going to the spark plug and fuel pump does not run as well when cranking engine over. I found a melted earth wire in the engine wiring loom and i tried tracing it but all it connects to is all the other earth wires which are all just joined together and then 1 big earth wires which going to battery negative. Before i buy a loom i would like to try get the engine started to at least know if engine is good.

I traced the fuel pump power wire and can see 2 wires, 1 is a earth and 1 goes to the ECU/CDI box.

i then traced the ignition coil wires and 1 is a earth and the other also goes to the ECU/CDI box so I'm thinking could the ECU be bad/fried?

i have ignition working, display screen works, horn and headlights work, brake light works etc just literally no spark and fuel.

i have manually tested the fuel pump with 12 volts and it runs no issues with 12V probe tester so pump is fine. I have also ohms tested the ignition coil and it reads 0.8 so within spec, Im thinking could the issue with spark and fuel be related together and if so where do i go from here. Is it likely i have a fried ecu?

Trying to do diagnose without a wiring diagram and not much information to go by if any at all

 

The fried earth will go to the rest of the earths in one direction but where does it go in the other? Just done a Google and got https://suprememotos.com/other_makes...-in-store.html so Spy Racing must be the importer and almost certain that they import some Chinese make and stick their own name on it. Which is why, only they will have info on a bike with that name, though it could be imported and sold under other names.

 

thank you for your reply, looks like the original maker of the quad bike is called JINLING and spy just rebranded it.

It’s just 1 earth wire connected to battery negative and all the other earths are joined to this 1 earth.

so all the sensors etc that need earthing at the front of the quad are joined to this 1 earth, the 1 earth then routes to the back of the quad where all the sensors at the rear of the quad will join to this 1 earth wire and then theres a wire that goes to the battery. Not sure if thats how it meant to be from factory as cant find a wiring diagram at all for this

 

guys not getting anywhere with this. I have disconnected kill switch to make sure thats not the cause and i cant see any fuel pump relays on the circuit, have checked all the fuses that i can see they are all good. The fuel pump wiring comes from the ECU/CDI which i dont see a way of testing and so does the ignition coil wiring comes from the ECU/CDI.

Is there anything else it could be before i bite the bullet and buy a ECU?

 

I have fuel pump running now!!! I also have 12 volts going to the ignition coil now but sadly no spark.

The red battery wire had a inline fuse and i dont think this fuse is meant to be there, after bypassing the fuse by connecting the red wire straight to battery I now have engine light coming on and fuel pump priming and ignition coil getting 12 volts but still no spark

Im thinking the ignition coil is bad now and for the sake of £15 i will just buy that and try it as it cant be power issue now as getting 12 volts

 

Contact Spy Racing and see if you can get a wiring diagram out of them. EFI equipped bikes have complex wiring and unless you know exactly what you are doing you can blow the ECU or other components. That overheated earth will be because too much power was put through the earth system and that one took all the strain. If there is another earth direct to the engine, check it is sound, otherwise all the power required by the starter may be going through that earth. If most of the electrics work when you short that red to the live post, there is a break somewhere in the pos wire supposed to be feeding that red. Trace it back to find the fault.

 

firstly thank you so much for taking the time to give your kind advice. I cant seem to find a spy racing website so not sure how to contact them.

Im done with the EFI side for now as i have fuel now so my next worry now is the no spark even though I am getting 12 volts to the ignition coil so i will trace the pulse wire from the stator which should be easy enough to do and replace the ignition coil as thats cheap enough to buy and go from there.

If im getting 12 volts to ignition coil does that mean my stator pulse wire is sending a signal to the coil?

The earth that melted I can see it joins to all the other earths on both looms and then goes to battery negative. So theres probably atleast 10 different components/sensors using the same earth and no way of checking which component it was that caused the melting sadly as not possible to trace the earth. I managed to find a original wiring loom for it so i am just going to replace the wiring loom to factory as whatever is going on with this loom it looks as if someones had a butchers at it and I dont think it should come like this from factory so maybe thats a problem in itself.

 

Also

if all earths are connected to each other on both looms and then theres the single earth wire which joins the 2 looms together… surely all the power from the components is getting sent through that 1 wire and possibly that 1 earth cant handle all the current being thrown at it

best way to figure this out I think would be to fit the original harness back on the quad to start fresh with it as trying to waste time on a harness thats been messed around with wont get me anywhere.. wiring diagram for the ECU would be great but not getting much luck with that.

 

"If all earths are connected to each other on both looms and then theres the single earth wire which joins the 2 looms together… surely all the power from the components is getting sent through that 1 wire and possibly that 1 earth cant handle all the current being thrown at it"

That is what I meant by check the earth to the engine, the chassis earths don't take a big load, lights is the biggest, possibly horn, but the starter does take a lot of power through it's earth. If the engine earth is loose or missing, all earth power is for through the chassis earth if it can. Anyway, spy racing's website is a strange black hole but this https://www.bizseek.co.uk/spy-racing-01403-788956 gives a phone number and address and implies they are still active.

 

Is ignition system DC or AC volts