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The crank position sensor

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Old Sep 14, 2009 | 03:34 AM
  #11  
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Here's a link to a site that has a pretty good explanation on electronic fuel systems.

http://www.nightrider.com/biketech/m...efi_basics.htm

American Iron had a article the last month or so about fuel controls system but I can't find a link for it this morning.
 
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Old Sep 14, 2009 | 05:53 AM
  #12  
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Originally Posted by hpfatboy
IM in CHAZ, NEED to no MORE!!! LETS KICK IT UP A NOTCH BOY'S!!!
Amen...Cant we get us a Crank sensor expert up in here!!!

I just know as my 05' settles into its "Golden Years" I will need to now whats really going on......
 
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Old Sep 14, 2009 | 07:35 AM
  #13  
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im beginning to think no one on hear has ever had a problem with theres or im just mabe its my stupid alarm that went south i have no idea and more any one want to buy a fat boy
 
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Old Sep 14, 2009 | 08:19 AM
  #14  
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So did you check for spark?. Either get a tester or have a buddy stick his finger in the spark plug wire end while you crank it over. If he hollers, you got spark.

My big brother did that to me when I was young and stupid and I'll never forget it.

The one on my Tahoe would work for awhile, presumably till it overheated, and then it would shut everything down.

It'll also shut down the fuel pump so you shouldn't be getting any fuel to the efi either.
 
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Old Sep 14, 2009 | 09:36 AM
  #15  
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Crank sensors are a magnetic switch, same as a ABS sensor, differance is the crank sensor only trips at TDC. It is used by the ECU to calculate fuel timing and ignition timing based on TDC from the crank sensor.

They can go bad sure, and fuel,spark will not happen. You can somewhat check them by ohm'ing it and rotating the engine slowly. You should see it blip from a open/closed circuit to the opposite at TDC.
Also being magnet they can attract metal particals and cause problems, a simple removal and check/clean of CPS end can cure that. Though I have never experienced this others have noted.

So do you get fuel or spark on your non start issue? I assume it is at least turning over. Are you completely stock or running a PCIII or some other piggy back unit?
 
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Old Sep 14, 2009 | 04:45 PM
  #16  
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Originally Posted by man4mopar
Crank sensors are a magnetic switch, same as a ABS sensor, differance is the crank sensor only trips at TDC. It is used by the ECU to calculate fuel timing and ignition timing based on TDC from the crank sensor.

They can go bad sure, and fuel,spark will not happen. You can somewhat check them by ohm'ing it and rotating the engine slowly. You should see it blip from a open/closed circuit to the opposite at TDC.
Also being magnet they can attract metal particals and cause problems, a simple removal and check/clean of CPS end can cure that. Though I have never experienced this others have noted.

So do you get fuel or spark on your non start issue? I assume it is at least turning over. Are you completely stock or running a PCIII or some other piggy back unit?
all stock hd download when i bought it did fuel pump last month and all in tank parts with that got spart gona use sum starting fluid right now will report back
 
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Old Sep 14, 2009 | 05:10 PM
  #17  
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ok this is geting the best of me i just shot i dont know mabe 4-5 shots of starting fluid in my fuel injector body while cranking it and she wants to come alive so it is a fuel problom i wonder what the funk it is but its gona kill me
 
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Old Sep 15, 2009 | 09:20 AM
  #18  
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Originally Posted by redbone62
ok this is geting the best of me i just shot i dont know mabe 4-5 shots of starting fluid in my fuel injector body while cranking it and she wants to come alive so it is a fuel problom i wonder what the funk it is but its gona kill me

Best cheap way to check spark is to pull a spark plug, attach to ignition wire as assembled, hold plug base against the aluminum head and turn over checking visualy for spark across the plug. Very important to keep plug against bare aluminum holding rubber boot not plug itself if is removed you may become the ground and feel a hell of a jolt. Prolonged lack of ground plug can cause damage to coil just a FYI, but if done as explained no issues.
Or purchase of a spark checker keeps it safer.

If your 100% sure you have spark but no fuel. Do you hear hear fuel pump cycle when you turn the run switch on? If you do the next things to check are fuel pressure fuel flow, injector spray and flow. If you do not hear it cycle, electrical needs to be checked, fuses, relay, wires and fuel pump itself.

I am not a fan of starting fluid
 
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Old Sep 15, 2009 | 10:10 AM
  #19  
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Just throwing it out there because I haven't seen it mentioned, but is your battery good? Are the cables that attach to it tight or loose? Just something simple to check before you do anything drastic.
 
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Old Sep 15, 2009 | 10:13 AM
  #20  
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I dont know if you solved the problem or not so ill go over a few things that it might be. In my experience as a tech ive had quite a few crank position sensors go bad. Typically when the sensor goes out the bike will be VERY difficult to start. I mean, it will just turn over and over and eventually start. Once it starts then itll run fine. I honestly dont know any tests for the sensor as when i would check everything else and narrowed it down to the crank position sensor i kept a working spare and would just switch it out for a known good one.

Second, if you have narrowed it down to a fuel problem then the first place i would definately check would be the fuel pump, specifically the fuel lines. I always use a fuel pressure tester and connect it between the quick disconnect coupling between the fuel line and tank. check the pressure. But assuming that you dont have a tester, the first thing i would do is pull the dash and the fuel pump plate. You can just take out the torx screws and lift it up not taking it completely out. then reconnect the dash and turn the ignition switch on. You will hear the fuel pump turn on for aprox. 5 sec. The thing you want to look for is any fuel spray in the tank. The hoses have a bad tendency of springing a pinhole leak in them and leaking back into the tank thereby giving you little or no fuel pressure even though the fuel pump is working.

I dont know how many people notice the fact that ever since they gas stations have switched over to a percentage of ethanol but more and more bikes get fuel problems. Ethanol eats plastic and rubber parts. If a car (or bike) will be running ethanol gas the fuel system has to have special plastic and rubber parts, o-rings, etc...
Being a tech i saw a huge increase in fuel problems with the implement of ethanol in the gas. Thats why if you look at the owners manual on an older car it will say that you should not run ethanol gas. Newer cars and bikes have the necessary changes in the fuel system to accomodate the running of ethanol gasoline. Older bikes dont.
 
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