2007 GSXR 750 starts, but doesn't run

[physicistkev]

This is a good one. After sitting for a few months I started the bike and got it out of the garage. It ran rough, almost like being out of fuel. Turned the bike off and opened the tank up. Looks like it's out of fuel. Put a little over a gallon in and tried to start. Engine fires for a brief second, that initial roar and then it dies.

I can cycle the kill switch or the key and it sometimes doesn't fire at all. Sometimes it fires and then dies. If I hold the starter for a few seconds it acts like it wants to start, but doesn't.

Cycling the key or kill switch, causes the fuel pump to come on and charge the system.

I have a PC-V and pulled the injectors and placed the stock ones back on with no change in behavior.

I charged the ultra light battery, just in case it was a low voltage issue and no change in behavior.

When I took the tank off, fuel would leak out of the hose as a slow drip if the fuel level was over the fuel pump.

I ran it about every 2 weeks for a few minutes, up and down the street, after the last track day with no issues. This went on until the beginning of September. Then it sat for about 7 weeks due to work, vacation, life and so on. The only change I have made in that time frame is adding my lightech adjusters and lifters.

I am thinking fuel delivery issue as it seems to fire better if you prime the fuel system by letting the fuel pump cycle. It's not consistent though.

Any ideas?

 

[NegativeCamber]

If it's not bad fuel or a gummed up fuel rack, I'm not sure what it would be. But, I noticed you said that it was very low on fuel. In my experience and from what I've been told, you should have the gas tank completely filled with fuel stabilizer over long periods of storage. If you leave the tank partially empty you run the risk of corrosion. The guy who sold me my bike kept his tank empty over the winter and it was really nasty inside.

So I'd consider having your tank completely full of fuel. Also, but I don't start my bike from the end of the season until it's time to start prepping it in early spring (5 months or so). The two seasons I've had it it's fired up no problem. That might run counter to what a lot of people do but it has worked for me and I plan to do the same this off season.

Good luck!

 

[physicistkev]

Agree about the partial fill, however the bike is kept inside a temperature and humidity controlled area. Large temperature oscillations, which cause the water condensation on the exposed inner surface of the gas tank is generally not an issue. I have a few boats, one with a 165 gallon tank, so I am all to familiar with the partial fill issue . When looking at the tank, there is no corrosion on the inside that is visible. I will pull the fuel pump to see if there is any debris from corrosion in the filter, since it usually starts in hard to see areas. Also to test and make sure the pump is working as it should.

I know that most modern bikes have a fuel start function, where they run a separate fuel "map" at initial start and then kick over to the regular fuel map. If this is true, the PC-V documentation talks about this, then it's possible that the PC-V could have lost its map or be damaged. I will need to look at the PC-V to see what it's thinking. I did replace the PC-V injector connections with the stock ones to no avail, but I don't know if I would need to disconnect anything else (TPS, of other connections to the PC-V). I will check these things out. Any one have any other ideas?

Thanks!

 

[D-Zum]

Did maybe something get grounded and zap your PCV's mapping when you disconnected the battery?

Can you maybe hook a laptop up to it and see if there's a map on that little beast?

 

[Dave561]

Is the bodywork any good, if so pm me a price; )

Sorry sounds a fuel delivery issue, but I'm just a rider

 

[Mike:p]

Was this issue resolved because my bike is doing the same thing.

 

[physicistkev]

Wiring harness issue. Replaced the harness, all is well. Apparently, this is common on 06/07 machines, or at least becoming more common. I don't know exactly where the fault is, but there is probably a bend that chafes a wire or something that degrades a connection over time.

 

[Mike:p]

Wiring harness issue. Replaced the harness, all is well. Apparently, this is common on 06/07 machines, or at least becoming more common. I don't know exactly where the fault is, but there is probably a bend that chafes a wire or something that degrades a connection over time.

You should dissect the old harness to see where the problem originated. That way I will know where to start if I ever have the same problem.

 

[tdelegram]

You should dissect the old harness to see where the problem originated. That way I will know where to start if I ever have the same problem.

Mike as stated before, definitely the Flux Capacitor! Wiring problems are a bitch, tracing each wire looking for worn or cracked insulation, volt ohm meter testing looking for internally broken wires, and lots of swearing. I would start with the fuel pump circuit, next ignition circuit, then and kill switch circuits like side stand, clutch lever, neutral switch.... Good luck.

 

[tdelegram]

Kev,

Last time I saw you was Barber about 4 or 5 years ago and you refused to ride my brand new bike, like you were too good for it or something! Hope all is well and paths cross at PIRC, Summit Main, or NYST this year.

Tom

 

[physicistkev]

I plan on going though the harness. Focusing on injector circuit and anything to do with "engine running" monitors. The fuel pump was fine. IT seems to be something in the actual injector 12V delivery or with a sensor that lets the engine know it's running.

I don't ride other peoples bikes, because I can't afford to buy a new one if something goes wrong.