Curing 2007 EFI problem

[agourabob]

I recently posted requests for help with a friends 2007 Big Dog, a California injected model that was quitting when hot. Would not restart for 10-15 minutes. A few suggestions were EFI module, crank sensor and others. Only for future help understanding the systems and procedures, I wanted to post the steps we followed.

Initially we set the bike up and ran it while observing the temperature at the intake manifold temp sensing bolt with a laser temp gun. The bike quit at about 300 degrees indicated, after cooling the sensor with a cold hair dryer, it started immediately and ran for 2-3 minutes. Was the bike too hot, or the sensor wrongly sending its signal.

We called S&S, spoke with their tech dept, they recommended changing the EFI module to a 49 state rather than a california profile. We did that, and no help, still quit when hot, although we were happier having that richer condition.

Next we downloaded their pro tune software, free from their website and with a usb to mini usb B style end, we plugged into the EFI computer, connector under the cover on top front of the EFI module. Best to use a windows XP machine for this. We went into the gauge setup on top, then into the advanced settings. The screen came up and displayed ALL internal running conditions of the motor including software version in the EFI unit, If ANY parameters were off during running, that box would go RED during the running. Oh, by the way, the original EFI module does NOT shut down the motor when over the temp limit, it is not programmed to do that.

When we ran the bike while on the program it showed head temps and timing, etc. When it quit, we lost RPM output signal, this being generated by the crank position sensor. To boot, we had a scope probe across the sensor, there was no output while cranking.

I guess we could have just changed the crank sensor from the beginning, but we wanted to make sure a module wasn't causing it. This did cost us more money to troubleshoot, but we now know what to do to analyze a big dogs ignition and EFI system.

I thank all that gave ideas, and i hope the info about S&S's very helpful software helps someone else through their problem in the future. A regular current production crank sensor fits all big dog motors. Best to splice it in close to the location of the sensor, connectors must be cut off the Harley sensor and the wires soldered and shrink wrapped.

Thanks Again
Bob

 

[woodbutcher]

i am sure this information will be much appreciated by the many EFI owners. Thank You, kind sir.

 

[Jwooky]

Great job diagnosing and analyzing the problem. Always better that just guessing and swapping parts.

I also like and use protune. Thanks to S&S for making it free and available for all to use.

 

[Sven]

Oh, by the way, the original EFI module does NOT shut down the motor when over the temp limit, it is not programmed to do that.

:2thumbs: Believe it for watt its worth, but my first guess was crank sensor. I think I was building bike/racing/ect. during that time. So I wasn't around so much to catch this problem. I also nailed that one years ago when someone kept changing the computer and wire harness and I told him not to. I said it was the crank sensor and sure enough it bled crank sensor. Another forum that threw me out too, I told the guy not to buy the crank sensor if it keeps firing up the bike. He bought one and it did the same thing. Turns out to be something he modified someplace else. Like I said, I paid the hard way to learn thishit called a typical copycat computer bike. I had to school myself with this stuff. Let me tell you it's very complex and easy at the same time. Think of it as; I had to formulate what no one else is looking at. I am chasing fundamental moves. The penultimate number that it has to follow to work.

1. If the computer starts the bike back up, it is not 'programmed' to do this as your analogy. You eliminate the ECU once it starts the bike. It shows even S&S is not even well versed at diagnosing the basics. Think about it. I just said if the computer refires the bike, it is not a motherboard all wrinkled and not seeing input and then sends the output? That's not how it walks, basically. And its too basic a step she goes stalling on a heat/goes cool issue.

2. The ECU is a digital component. It is a calc box and that is it. It waits for input. So when something heats up, think of the sensor as a heating blanket. It has many ranges of heat. It can send out heat to your skin, but you soon find out it doesn't heat like it used to. So like a diode heating up and almost catching the pad on fire, you see a black spot in those coil loops. In other words the crank sensor sends in clock speed in a wave from. So analog means 'many.' And when it heats up it exceeds the written data. It could send out zero as data until it cools down. All the ECU can do is receive junk and then send out junk. It says the output side cannot recognize that frequency either = No Start.

3. So too is the wire trick. Not your antique bike's telemetry sort of speak, but watch the wires. If you have 3 wires out of a sensor, it is tied to a 5v ground, one to the ECU, and the other wire to a sub-system that is tied in. An example would be; the speed sensor is tied into the gear position sensor that is tied into the speedo meter. So once a 3 wire sensor fails, that wire going into the ECU sees a lost input, sets a limp mode to save the engine from damage. This is called a 'backup/fail-safe/limp mode, so you still can ride the bike safely home.

4. The 2 wire sensor goes from a 5v ground, thru the crank sensor and out to the ECU as an input signal. That is one continuous frequency wave form called a square wave. So once that coil winding cools, heat is part of the data. Heat makes the wave pulse. Over heat it, you probably get a pulse range that is not written for said heat, meaning, if they can set the heat to this range, so can you pick a range and build the sensor with a set value you better stay within.

5. And with a 2 wire sensor you lose the crank sensor, the bike is a boat anchor = Period! Once again, for those owning computer bikes down the road, here is something else about the cam sensor, and not necessarily your dog, but back to the basics of the computer bike; being generic. The ECU is taking in data and can dump stuff instantly, or goes thru a few second process once a sensor fails. So once the cam sensor fails, unlike the crank sensor that fails without a backup, the cam sensor too acts as another boat anchor event. The ECU recognizes the cam going belly up, continues firing the engine till you stall it or get it home. Once it is turned off, RAM or a random number is now ready to be read with key on. The last good known input value was saved so it continues firing, but what happens when the computer is waiting for that [key on] input signal? It has been saved by the ECU [while you were riding it home], but it is now a junk number not recognizable = Junk Cam Sensor/slash/boat anchor #2 in the generic. The crank and cam are the only 2 sensors that won't start the bike. Every other sensor on the bike is not needed because of the backup system. You won't have FULL POWER if in limp mode, but it got you home none the less.

6. You can call S&S back, see if the'll fly me out there, set me up with food/trans/roof, I'll run a seminar over there for techline help??? For fucksakes! I even bought different 2 different bikes [open/closed loops] to R&D to see WATThe compeetissues are withose [2 bike's] issues? Maybe we can pig trade for WATTs Behind Door #2 over at S&S? Yeah right. I'll take "Penultimate Number" for $300, Alex. :flag:

Remember, Ivan's PeeFourmAnts in his pants and I have history. Figured his act out years ago. Same goes for flashing too. GeeeeeeHA!


NOLTT (no one listens to turtle):Yawn: