Well, I pulled the IAC off and cleaned it again. It was actually pretty clean, I guess spraying the cleaner in and wiping with Q-tips worked. Put everything back together and took a ride, great weather by the way 80 and bright sunny day. Any way, same thing, only happened once but, that was with only 4 shut downs. Same thing, won't start, backfires at the intake. Stop cranking, wait a few seconds and starts up like nothing was different. Starts great 90% of the time, just every now and then starts like crap. I replaced the fuel filter and in tank fuel line but, that didn't help either. I"m at a loss.

 

Backfire at the intake usually means running way too lean, or bad timing. Timing fault would most likely throw a code.

One wonders about the injectors, and the wiring leading to them. Faulty or loose connector, maybe a wire broken inside the insulation?

 

I have seen similar problems with TPS voltage being out of range, and also fuel pressure problems. I may have missed it but have you checked your fuel pressure?

 

Mine does the same thing from time to time. I just bump the starter a time or two, the she usually fires right up. I think my problem is heat soak in the motor creating more compression as the rings fit tighter to the cylinder walls when she's good and warm.

 

Unfortunately, I don't have a way to check the fuel pressure right now. I removed the tank, "AGAIN", pulled every connector I could find off, cleaned and put dielectric grease on each one. Put everything back together and now for the test ride. I'll let you all know the result.

Edit to add, when I pulled the MAP sensor out, it was really nasty. I cleaned it up also and reinstalled. Don't know if this had anything to do with my problem but, I was there any way so.....

 

Update: After a 280 mile round trip to the coast yesterday the bike is running fantastic but, the issue with starting is still there. I was trying to pay more attention to the symptoms this time and found one issue I hadn't considered. When the starting issue happens, not only does it backfire thru the throttle body, I smell raw gas for a couple of seconds when it does start. Could the issue be flooding? Could the injectors be leaking and adding more gas in the combustion chamber? I just don't know I have very little experience with fuel injection. Is that a way to test the injectors?

Edit to add: These injectors have 62,000 miles on them.

 

Yes, like I said with a pressure gauge, and watch if it drops, or pull the injectors, leaving the line connected and see if they **** after the ignition is shut off. Be sure to crank the bike a few seconds to build up pressure, and use a rag to let the gas squirt into. Thought I mentioned this back a while ago

 

Thanks Charlie. You did mention that earlier in the thread and I appreciate the information. I guess I gotta buy a pressure gauge that works with fuel injection.

 

frankly the easiest way is to pull the injector rail. set the tank up a little, and keeping the fuel line connected crank the bike. fuel pressure will rise as the ecu sees a signal from the crank position sensor. then shut off the key and see if the injector drips after the key is off, and it sits a bit. ,That way you don't need a gauge that you may only use once in your life. If they don't drip, you will need to find some way to see if line pressure is dropping off, that may include a gauge at that time. could be something inside the tank bleeding off pressure

 

I'll find out. I just ordered a "Fuel Tool Pressure Gauge". It is an inline gauge that will hook up directly to the tank and fuel line. A bit pricey but, I need to get this fixed. I ride too many miles to deal with this all the time plus, I don't think it could be running at its optimum with this kind of issue. Time will tell.