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2003 Kawasaki ZX-12R
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Discussion Starter · #1 ·
So in hopes of finding my electrical prohibiting my PCV from getting a proper rpm reading, I have gone through various connectors of my bike measuring voltages, what has me puzzled is the white red wire voltages which powers the injectors, fuel pump relay, and fuel pump is showing some odd readings. Now with my fuel pump connected my fuel pump relay indicates 12.3 V at the W/R and even slightly less at the fuel pump connector. The W/R wire shows 12.08 at the ECU, however whenever I disconnect the fuel pump itself the voltages throughout the system show a healthy 13.0 V at the fuel pump relay W/R wire, fuel injector W/R wire AND the ECU W/R wire terminal (left side of center plug right under a ground wire). I guess I'm wondering if it's possible that the fuel pump itself is causing issues throught the rest of the fuel system in the bike. ECU grounds are all good, power also seems to be good terminal 48 (White wire) shows 13.1 with a drop to 12.8 when priming, terminal 17 (White Yellow) shows 12.4 while priming then 12.97 thereafter (manual specified 12.5V or more when IGN on so I assume this is within spec), additionally I have gotten a second ECU just to rule out a possibility of a bad ECU and the readings are the same. Thoughts or recommendations regarding what I should look for next or check? When doing the fuel pump test with the Y/R to BK/W connectors at the pump I would get a reading of aprox 12.0/11.9 V which is far bellow the actual battery voltage that the service manual says i should be reading however the manual itself has no indications as to what to do with a low voltage reading. Any help is appreciated
 

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This is interesting as I will be doing a complete electrical & fuel system check on my 12 sometime in the new year for persistent and progressively worsening starting problems - apart from usual stator problems I've had in the past.
I have previously replaced ecu & even the main wiring harness due to small cracks/breaks in some wires in various areas of the electrical system. Bugger isn't it?!!
 

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2003 Kawasaki ZX-12R
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Discussion Starter · #3 ·
Indeed it is, luckily these old bikes don't have TOO much wiring, still a headache nonetheless. I have a buddy who used to work at motec and am contemplating having him make a custom motec grade harness so I don't get any more pinched wire surprises. What stator do you use by the way and how do you know when your stator is done? I just replaced my (I assume) OEM stator with a ricks stator as the oem was grounded and I only found out because it melted my connectors to the reg rec ( I had converted to separate connectors already), when i pulled it out the magnets werent even magnetic anymore. Now the wires no longer get burning hot and I preemptively put bullet connectors on the ends. Attached is my old stator.
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The blackened sections of the stator are usually the burnt out parts.
Doing the stator output voltage check shows if one or more of the phases has done this.
I currently have a Ricks stator, but have also had the previous oem stator re-wound by a motorcycle autoelectrician. That lasted for about 2 years, burnt out again and he re-wound it for free. He did state that is was not a permanent fix.

Currently my stator is showing voltage output within spec, so I have to look further in case something else is drawing power, even when the bike is off. I have a Japanese MOSFET reg/rec too.
 

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2003 Kawasaki ZX-12R
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Discussion Starter · #6 ·
Haha I don't think that's edible anymore. In other news I found A) some nice pinched wires going to the front of the bike (right side of frame) that I repaired. Also all my coils have their primary windings shorted. This may very well be my issue with my rpm signal for the pcv as I've seen someone on a different forum report bad coils as the issue. The rpm signal at the connector is a consistent 12+ volts so I don't believe the issue lies with the injectors themselves however the fuel pump might still be corroded and causing excessive voltage drop in the circuit.
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Discussion Starter · #7 ·
Also I'd like to ask if any of you know what could cause the coils to short in the first place. I did replace them before I replaced my reg rec so maybe that's the cause of it?
 

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Remember primary stick coil winding will only measure about 1 Ohm resistance so you have to have a good meter on the lowest resistance setting, don't forget to short your meter probes together and measure any meter resistance first and then subtract that.

Was that the tank that rubbed through the loom?
 
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Discussion Starter · #9 ·
Nope, the harness actually got pinched at the grouping/guide bracket by the triple tree. Also regarding the coil the reason I believe it is shorted is that the coil was showing 0 ohms for primary but within spec for secondary. My meter, within the resistance setting it was at, shows zero ohms, in fact I think it shows 0 for all the resistance settings it has (will confirm). I'm not to sure about this being what you would call a "high quality" meter but it seems to read about right and I'll have to check what you mean by lowest resistance setting, I'll take a picture of the setting I used and at both ends of the resistance settings for reference as I am not very electrically literate.
 

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Discussion Starter · #10 · (Edited)
Well a look into the service manual and it all makes a lot more sense. Thanks for pointing out the resistance settings Yorkie I overlooked that they are specified differently for each winding in the manual. I will measure the peak voltage through the ignition system nonetheless to verify its all in proper order, if it is that would mean that my issue may very well lie within my fuel circuit
 

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Discussion Starter · #11 ·
I would appreciate if someone here had the time, to check the voltage at their blue red wire at the fuel injector connector by the TB when the fuel pump primes, and by the big square connector that goes to the ECU for reference. As well as the power wire going to the TB harness (either red or white and red can't remember). Thanks
 
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