krexken
Zone Head
Posts: 732
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posted September 24, 2008 07:35 PM
Hot Start Problem-Turns Over, Won't Fire
Hey strangers, I mean dudes. Just got through putting a Competition CNC's head (thing of beauty) on a customers '00 12 and it cranks and runs fine when the engine is cool but after it's warmed up, forget about it. Spins over fine but won't fire. Has fire at plugs. Did the light bulb trick (per manual) to see if injector is working. No light. This really has me baffled. I can't see why engine heat would cause the injectors to not cycle. I wiggled every wire and connection I can think of and nothing seem to help. Could low fuel pressure keep the injectors from cycling? ANy tips appreciated.
  
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JACKSHOW
Novice Class
Posts: 44
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posted September 25, 2008 02:01 AM
Fuel pump relay?
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NINJA12
Needs a job
Posts: 3310
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posted September 25, 2008 08:46 AM
How fast is it turning.
Try to boost it when hot.
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aliveagain
Needs a life
Posts: 5033
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posted September 25, 2008 05:00 PM
I've heard of coils opening when they get hot so it could be a relay.
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krexken
Zone Head
Posts: 732
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posted September 25, 2008 07:23 PM
I'm beginning to think it's the ECU. Hopefully a friend has one I can try. It has spark at the plug and the engine spins over plenty fast. The fuel pump runs and pressures up. The injectors simply won't fire for some reason, but only when motor is good and hot. I've sidestepped the powercommander also.
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rgeorge
Expert Class
Posts: 220
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posted September 25, 2008 08:06 PM
Do you have any FI codes?
Crank sensor?
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krexken
Zone Head
Posts: 732
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posted September 26, 2008 11:06 AM
No codes.
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Phantom13
Zone Head
Posts: 736
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posted September 26, 2008 02:16 PM
 Edited By: Phantom13 on 26 Sep 2008 22:21
What is the compression set at?
High compression engines sometimes have these hot start problems when the battery gets weak. If the battery checks out fine, then they require a 24v starter system for the extra cranking power.
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krexken
Zone Head
Posts: 732
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posted October 01, 2008 11:09 AM
Has a 1270 kit so it's pretty high. The battery isn't weak. It's spins plenty fast. It's losing it's ground signal for the injectors to fire. It has 12 volts at injectors. The injectors simply won't cycle to get fuel. It still fires the spark plugs. Fuel pumps cycles. I've tried 2 other computers and it does the same thing. It really has to heat soak to stop cranking and it won't crank again until the engine is stone cold. I've gone over pretty much every inch of wiring and the connectors. I guess it's time to start swapping out all of the sensors.
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entropy
Moderator
Posts: 8671
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posted October 01, 2008 01:13 PM
Ken,
it wouldn't happen to have a Muzzy shifter on it? Digikill2?
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krexken
Zone Head
Posts: 732
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posted October 01, 2008 07:28 PM
Nope. PC3 is disconnected also. I just knew that would be the culprit. You might be on to something though. It's using an air kill (whoever said they don't work on injected bikes- eight years without a hitch)and I think it's killing the spark but it's possible someone tied it into the injectors. Thanks
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KZScott
Needs a life
high on speed
Posts: 7235
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posted October 02, 2008 01:11 AM
!
Ken can you do that with a normal kill box that usually kills the coils? get it to kill injectors and coils at the same time maybe? (ideas for my bike)
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00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
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VincentHill
Needs a life
Posts: 6520
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posted October 02, 2008 01:12 PM
Have you tried to bypass the Fuel Pump relay with a small Jumper wire so that you have fuel pressure all of the time? Be careful to make sure which wires to Jump because you can blow the ECU (Do not ask me how I know! !)
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krexken
Zone Head
Posts: 732
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posted October 03, 2008 11:06 AM
Haven't tried that, Vincent. I've got two spare ECUs so I might. LOL The injectors are losing their ground signal when the engine is hot. All else is normal.
Scott. I've never tried it and never really seen a need to, even with some heavily sprayed bikes. Not saying it won't work or help though, just never have. It would be easy to do. One hot wire feeds all the injectors, the same as the coils.
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krexken
Zone Head
Posts: 732
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posted October 03, 2008 09:52 PM
Puzzle has been solved, finally. Turns out that old, stinky, oxygenated fuel doesn't burn very well in a hot motor. I figured out that the injectors only spray one time when cranking. That's why I wasn't getting my test light to light up just turning the motor over with the starter. It'll light up when the motor is running though because, naturally, the injectors fire when the engine is running. So I cut the existing gas in half with fresh stuff and lo and behold, she cranks all the time. This guy is gonna crap when he gets my bill. LOL Thanks for the help guys.
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tuusinii
Pro
Posts: 1031
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posted October 04, 2008 02:06 AM
Yes, always start with the simpliest possible explanation. I've also learden it the hard way after trying to start bike after the winter break. I tried all kind of things but she fired instantly after I put some new gas in! Good that You figured it out!
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aliveagain
Needs a life
Posts: 5033
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posted October 04, 2008 04:21 AM
So if this guy is going to the track and his map is for the oxygenated fuel,which would be the only reason to use it, what is he suppose to do? I'm missing something, how did you solve the problem?
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I wondered why the baseball kept getting bigger. Then it hit me.
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VincentHill
Needs a life
Posts: 6520
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posted October 06, 2008 07:22 AM
Stay away from Shell gasoline! In a Porsche 911s the engine compartment is too hot for the Fuel additives they use to make the fuel vaporize and caused the engine to Vapor lock! Only changing to any other fuel did that problem go away!
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Made History @ Daytona and still one fast old man!!
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