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What is this for?

10K views 16 replies 8 participants last post by  rep 
#1 · (Edited by Moderator)
I've just picked up a 2008 GSXR 600. Its been sitting a while but it was firing before I took it home, just not idling. When I got round to working on it, it turns over but won't fire. I changed the spark plugs, nothing.

So I went through the whole system: Fuel pump; fuel filter; hoses, injectors; everything is like new. Bike's only done 7500.

There is enough fuel pressure in the fuel rail to force the injectors off, but nothing from the injectors. The are not letting any fuel through. And they don't pulse or pump or do anything when the bike is turned over.

I've got power getting to the injector connectors, so I don't know why they aren't pulsing fuel.

The biggest mystery is this plug that runs off the fuel rail, with about a 6inch reach (see pics). I have no idea what it is or where it goes. It has power running through it too. What are dis??

http://i1168.photobucket.com/albums/r485/cjwork1975cjwork1975/plug_zpsempzcc0n.png

http://i1168.photobucket.com/albums/r485/cjwork1975cjwork1975/pulg3_zpszvkhjfr1.jpg

http://i1168.photobucket.com/albums/r485/cjwork1975cjwork1975/plug1_zpsbbch8cro.jpg







 
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#2 ·
Gonna move this to the Tech section.
 
#3 ·
What are the colors of the wires going to that plug (3 wires?)

The TOS (tip over sensor) is three wires and will allow the bike to crank but not start. However, I don't think it's in that area on your bike. It should be behind the battery.

If this is the case, you would also get a flashing "FI" in the temp window.
 
#4 ·
That's for the EVAP or PAIR valve... I don't remember which one, but I want to say it's the PAIR....

The TOS is further back, by the ECU in the tail area.


Unplugging it won't prevent the bike from running, your problem is elsewhere, but they will both throw an FI code. Putting a 2.2K Ohm 1/4Watt resistor across the two terminals will remove the code.
 
#11 ·
Found a wiring diagram online that the firewall allows me to get to...


The EVAP valve has an Orange/White and Dark Brown wire going to it..Dark Brown and Dark Grey both tend to look similar.

Leaving this unplugged will only cause a FI light, but the engine should still run.

If you're checking things with the airbox off and trying to run the bike, then the guys above are correct, the IAT sensor needs to be plugged in or you'll have yet another code. I think the bike will still run though.
 
#16 ·
Thanks for everyone's help, looks like it was the EVAP plug.

EVAP system is conspicuous by its absence, though, thankfully it's not throwing a code.

All this computer, FI and ECM bollocks is new to me. Last bike I worked on in any real depth was a 99 ZX6R, which I think had none of those things.

Still, with your advice, and a crash course in engine management, we figured it out and now it runs like a dream. It seems like it needed the IAT plug being disconnected was the reason the injectors were on strike, but it could easily have been something else that we fixed accidentally!

Either way, thanks again for all the posts!
 
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