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Discussion Starter · #21 ·
I don't know why my edit did not show up when I posted it 30 min or so ago, but I went back and rechecked everything. I must have been checking the wrong terminal in the wiring harness, as there is NOT a voltage from the pink wire. I have no idea how I managed to bungle that up, but I did. Can I bypass that diode circuit entirely to make sure that's where the problem lies?

Awaiting instruction :)

Donated to the site. This is more than worth it.
 

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Old, Bold rider
2002 Honda 919, 1976 Yamaha XT500 cafe, TC-JAG TZ250
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Ryan:
It sounds like the ECU is not powering up or initializing.
If you haven't already done it, disconnect the power commander and restore the wiring to as close to original as you can, in a process called 'returning it to zero." Then carefully check all the pins in the ECU connectors for engagement depth, bending (as if you haven't already), and for the integrity of the conductor's connection to the pin. To explain, sometimes if a wire is stressed the copper conductor will fatigue fail while the insulator outwardly looks fine. It doesn't make a connection but looks like it does. Of course backprobing the pin with a meter should show this, but sometimes pushing the probe in drags the wire forward far enough to make a temporary connection and a false "it's okay". To check for this, simply gently pull the wire back from the connector body. If the wire is good it will feel solid as soon as the free play of the pin is taken up, but if it's broken it will continue to pull back with an elastic feel as the insulator stretches. Obviously, it will have to be repaired.

One thing I forgot to include in the abbreviated wiring diagram is a second ground -- a Green / Pink wire right next to the Green in the connector. It is connected to the the chassis ground lug on the frame as opposed to the Green which is (I think -- I've never been able to actually find it) bolted to the engine and serves as a logic ground and reference for the VRef 5V. The G / P wire does the heavy lifting of grounding the injectors, ignition coils, and iternal power supply VCC. What the heck -- redo the chassis ground whether it looks like it needs it or not. it couldn't hurt.

I also recommend voltage checking the Black / *********** feed wire at the ECU connector.

I know this sounds a bit scattergun compared to the logically laid out troubleshooting tree before, but once you're down to this level, it's usually "What if this is not right ... hmmmmm."

I hope this helps some, but it may come down to a smoked ECU. I'm just trying to be sure before spending a bundle of your money for it.

Good luck.
 

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Discussion Starter · #23 ·
Appreciate your help on this.

The power commander was the first thing to go. Pulled it out to see if that was the problem. All of the pins in the wiring harnesses look good. I did not check individual wires or anything else you mentioned and unfortunately it will have to wait until Tuesday night as I'm out of town tomorrow night.


Next time I'm visiting my friend in Woodland Hills I owe you a beer! (drove past Calabasas 6 weeks or so ago)

edited...
 

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Old, Bold rider
2002 Honda 919, 1976 Yamaha XT500 cafe, TC-JAG TZ250
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I don't know why my edit did not show up when I posted it 30 min or so ago, but I went back and rechecked everything. I must have been checking the wrong terminal in the wiring harness, as there is NOT a voltage from the pink wire. I have no idea how I managed to bungle that up, but I did. Can I bypass that diode circuit entirely to make sure that's where the problem lies?

Awaiting instruction :)

Donated to the site. This is more than worth it.
Oh dear -- how fallible of you. In other words, human. I once spent over 20 hours troubleshooting a problem in a radar system based on a voltage taken from the wrong pin 3 days previously. It happens.

Unfortunately, the zener diode is there to provide a regulated voltage lower than 12 volts, and I wouldn't be surprised if Honda designed the ECU to occasionally vary the load on the wire to test for a resistor in place of the diode and cut out the ECU. If the information posted by doctoremoto (thank you!) is correct, the diode is rated at 11.4 volts, which is an unusual value and therefore not available at an electronics store. As it is integrated into the switch assembly it may be necessary to replace it as a unit. Before ordering one check the condition of the pins in the ignition switch connector, there may be some corrosion that would block the high impedance signal. Hopefully a thorough cleaning will take care of the problem. Also point to point check the pink wire from the ignition switch to the ECU -- there are no intervening connectors, so if it shows open, look for external damage or chafing on the main harness which may indicate where the break may have occurred.

Good luck, and thank you from all of us for the donation.

Rob
 

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wellcome to my club! :))
when is eny problem like this first check pink wire must have around 11.4v with ignition on .if you don't have that voltage (when red has battery voltage and red/black a little less ) than is the electrical part from the ignition switch.can be replacet.second.the black\white wire from ecu must have battery voltage or a little less.the black\white wire powers up everything.(gray connector 2-nd pin). if you don't have +battery v on the black\white and -battery voltage on brown\black from fuel relay,it's mean something keeps blocket the ecu.can be the engine stop switch or .....
 

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i just want to say...WHAT UP BBA !!!

good to see ya arounnd so to speak...

l8r

+5$
 

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Old, Bold rider
2002 Honda 919, 1976 Yamaha XT500 cafe, TC-JAG TZ250
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And he cooks too. :lurker-eating-popco
Of course! To see a 7 foot tall flame from my Calphalon saute pan while searing onions, chipotle peppers, cumin, and brussels sprouts in a couple ounces of Maker's Mark while stirring the walnut risotto and mentally keeping track of the pork ribs on the 'que is one of the great pleasures in life. Cooking is not for the faint of heart.
You should try one of my portabello mushroom, kasseri cheese and habanero omelettes some time -- it'll knock your socks off!

Rob
 

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Discussion Starter · #30 ·
i just want to say...WHAT UP BBA !!!

good to see ya arounnd so to speak...

l8r

+5$
Howdy sir, long time no see. Good to be back, will be better to be riding again, and will be best when the bike looks as it should again.

DISCLAIMER:

When I, with the eensiest bit of help from a certain GOD in this thread (sarcasm fully intended), realized that the problem was likely a wire and possibly at the front end of the bike, I just assumed that this was all my fault. After I got rocked by that minivan, I had no gauges, light, etc, and I being the minimalist that I am decided that I would cut out all the extra wiring that I could. You might notice that my front end looks just a hair different from most 919s ;) . I of course left anything that I didn't know the full purpose of. I figured something came loose or had corroded to the point of no longer working.

Possibly tomorrow, I'll post a photo of the brick of wire I took out of the bike. It's really quite impressive. This all worked flawlessly for 4 years.

Now. Got a good look up there tonight. I think I might have found a bad connection, ya know... pending further testing. Have a look for yourself! It's like "where's waldo?"!



Tomorrow I'll pick up the security torx bits and I'll be back in business in 20 minutes.

In other news, I got pissed at the mini-fairing that I've never been completely happy with and, since I had misplaced my 10mm wrench under a piece of paper and didn't care to look for it, ripped it to pieces and proceeded to cut it off with a pair of side cutters. Finally, back to a round headlight for me!

The front fender and tail section will be painted to match the tank, satin black w/ glossy emerald green up the middle, and the front wheel needs repainted with emerald green as the guy who painted them for me originally quite obviously neglected adhesion promoter on the front.

I'm also going to cut my stainless header up to replace this black piece. I could do without the rust

The bike as it sits in the shed right now.



Thanks all. Will obviously post final photos once it's all painted up.
 

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Discussion Starter · #31 ·
I suppose I should also say that it appears that my wiring was fine. I soldered and shrunk everything and left plenty of slack everywhere. There doesn't seem to be much tension on the wiring from the ignition and the other wires appear to be fully intact. I'm not completely sure why I got a break where I did, but I suppose that question might be answered when I open up the lower part of the ignition.
 

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Discussion Starter · #32 ·
Running. Cleaned it. Serviced it. Painted it. Thanks for your help guys, especially robtharalson! Will post a pic or two after I get a fiberglass basket made and a round headlight mounted.
 

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That is one of the nastiest looking 919s I have ever seen. It's a shame you have to put a headlight on it. I kind of like it just the way it is. Why don't you try to put 2 really small, side by side headlights on it. You need to show off those forks! I like that color green. I'd paint the whole thing that color.
 

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I tried following your procedure but I had issues testing the pink wire do to the little rubber insert. Do you know where I can get the wire test harness? According to the 2002-2003 CB900 Service manual, the part number is 07YMZ-0010100 but I can't seem to find it anywhere.


You're going to have to be methodical here.

First, you will need a digital volt meter and one red and one black jumper wire about 3 feet long with aligator clips on one end and sharp probes on the other.

Second, look up the wiring diagram either in the service manual or in "Wrist Twisters Riders Forum > The Machines > Naked Bikes
Helpful Topics for 919 owners:" About 2/3rds of the way down in "Maintenance/Helpful How-To's" is a wiring diagram which will open in a separate window. I recommend saving it to a file in your computer for future reference. Familiarize yourself with the entire fuel pump control circuit including the pump, relay, fuses, grounds, and the relay control from the ECU. Take notes for reference while troubleshooting.

Here we go

Preparation:
Remove the seat and tail piece. Open the fuse box and check all fuses, then remove the headlight fuse. This will extend battery life during testing. Pull the middle of three relays away from its holder. This is the fuel pump relay, and your primary focus for much of the troubleshooting. With the meter, check for power to and from the 20 amp PGM - FI fuse. It is constantly powered directly from the battery (through the main fuse mounted on the starter relay). In all fuse tests, use the exposed metal lugs at the top of the fuses -- it's why they are there. If there is power to both sides, press on. Do not turn on the key unless directed to do so, then turn it off at the conclusion of each test.
Whenever I say Zero volts (0V), it can be as high as 1.5 V or even a little more unless I indicate otherwise.

Getting to the meat of it:

1-- Turn the key on and check for voltage at the Pink wire in the 22 pin gray connector at the ECU. This is a signal from a zener diode in the ignition switch that acts as an ECU reset. It is there to prevent the ECU from initializing if the bike is hot wired.
**** +11.5 Volts (V) -- Normal. Proceed to #2
**** 0V -- Either a broken wire or a defective diode, Find out which and repair / replace the electrical part of the switch.
**********************************

2 -- Making sure the kill switch is on, turn on the key and with the meter check for power at either Black/White wire going to the fuel relay.
**** +12V -- Cool. The EFI system is powered up. Go to #3
**** 0V -- Pull the engine stop relay (the one nearest the fuse box) away from the holder and check for power to the relay on the Red/White wire.
****** +12V -- The relay is getting power from the PGM fuse. Check the black wire for power.
********** 0V -- A problem in the kill switch or wiring. Fix it.
********** +12V -- The relay is getting power from the kill switch. Check the Red/Orange wire for power.
********** 0V -- The relay is getting a ground from the bank angle sensor. At this point, the relay is getting everything it needs to operate and may be defective.
********** 12V -- No ground from the bank angle sensor. Find out why.
***************************************************

3 -- Check for voltage at the Brown wire in the connector for the fuel pump relay for approx. 2 - 3 seconds after the key is turned on.
**** +12V -- The relay is providing power to the fuel pump. If the pump does not run, go to #4.
**** 0V -- Check for voltage at the Brown/Black wire in the connector for the fuel pump relay for approx. 2 - 3 seconds after the key is turned on.
******** Greater than 6 V -- There is insufficient ground from the ECU to activate the relay consistently. Possible poor connection or defective ECU.
******** Less than 3 V -- Normal reading. Cycle the key while holding the relay to feel for a click.
*********** No click. The relay coil may be open. Replace the relay.
*********** Click. Possible burned contacts. Replace the relay.
******** Between 3 and 6V -- Bad / intermittent connection between the relay and the ECU. Find and repair.
******************************************

4 -- Tilt up the tank and find the fuel pump / low fuel 3 pin connector. Wrap a clean shop towel around the red jumper's sharp probe to prevent shorting it to ground then clip the red wire's alligator clip to power at the starter relay. Be careful with the probe: it is hot at all times. Leaving the connector plugged together, jump +12 volts to the Brown wire in the fuel pump connector. Do not apply battery voltage to the Brown/Black wire. It may damage the low fuel sensor in the tank.
**** Fuel pump runs -- Poor connection between the relay and the pump. Repair.
**** Pump does not run -- Leaving the jumper in place, ground the Green wire with the Black jumper. Make sure it is securely grounded to the frame.
******** Pump runs -- Defective ground. The main ground for the most of the electrical system is on the right side of the frame near the rear of the tank. Check this for a loose bolt or corrosion. Correct as necessary.
******** Pump does not run -- Defective pump, broken wire between the 3 pin connector and the pump, or gremlins. Replace the pump, repair the wiring, or have an exorcism done (or whatever it takes to get rid of gremlins).

This may all look intimidating, but if you take it one step at a time you'll probably find the problem.

Rob
 

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Old, Bold rider
2002 Honda 919, 1976 Yamaha XT500 cafe, TC-JAG TZ250
Joined
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2,480 Posts
I tried following your procedure but I had issues testing the pink wire do to the little rubber insert. Do you know where I can get the wire test harness? According to the 2002-2003 CB900 Service manual, the part number is 07YMZ-0010100 but I can't seem to find it anywhere.
No need for the jump harness. To test probe any wire in a hermetically sealed block connector simply modify a safety pin as follows: open up one coil of the spring with a flat blade screwdriver (image 1) and insert the test probe through it such that it is securely held(picture 2). Slightly blunt the tip to prevent damaging the rubber seal, and clip off the clasp end of the pin. I recommend wrapping the spring / probe with a couple layers of electrical tape to prevent exposure to whatever circuit you're testing. Coat the tip with clean motor oil and insert it into the appropriate well between the rubber insert and the plastic of the connector body. Continue to push it in, angling toward the wire, until it encounters a hard stop -- this is in contact with the metal of the pin. It will make a perfectly good connection for test purposes.

Good luck!

Rob
 

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Time to roll up your sleeves!

You're going to have to be methodical here.

First, you will need a digital volt meter and one red and one black jumper wire about 3 feet long with aligator clips on one end and sharp probes on the other.

Second, look up the wiring diagram either in the service manual or in "Wrist Twisters Riders Forum > The Machines > Naked Bikes
Helpful Topics for 919 owners:" About 2/3rds of the way down in "Maintenance/Helpful How-To's" is a wiring diagram which will open in a separate window. I recommend saving it to a file in your computer for future reference. Familiarize yourself with the entire fuel pump control circuit including the pump, relay, fuses, grounds, and the relay control from the ECU. Take notes for reference while troubleshooting.

Here we go

Preparation:
Remove the seat and tail piece. Open the fuse box and check all fuses, then remove the headlight fuse. This will extend battery life during testing. Pull the middle of three relays away from its holder. This is the fuel pump relay, and your primary focus for much of the troubleshooting. With the meter, check for power to and from the 20 amp PGM - FI fuse. It is constantly powered directly from the battery (through the main fuse mounted on the starter relay). In all fuse tests, use the exposed metal lugs at the top of the fuses -- it's why they are there. If there is power to both sides, press on. Do not turn on the key unless directed to do so, then turn it off at the conclusion of each test.
Whenever I say Zero volts (0V), it can be as high as 1.5 V or even a little more unless I indicate otherwise.

Getting to the meat of it:

1-- Turn the key on and check for voltage at the Pink wire in the 22 pin gray connector at the ECU. This is a signal from a zener diode in the ignition switch that acts as an ECU reset. It is there to prevent the ECU from initializing if the bike is hot wired.
**** +11.5 Volts (V) -- Normal. Proceed to #2
**** 0V -- Either a broken wire or a defective diode, Find out which and repair / replace the electrical part of the switch.
**

2 -- Making sure the kill switch is on, turn on the key and with the meter check for power at either Black/White wire going to the fuel relay.
**** +12V -- Cool. The EFI system is powered up. Go to #3
**** 0V -- Pull the engine stop relay (the one nearest the fuse box) away from the holder and check for power to the relay on the Red/White wire.
** +12V -- The relay is getting power from the PGM fuse. Check the black wire for power.
** 0V -- A problem in the kill switch or wiring. Fix it.
** +12V -- The relay is getting power from the kill switch. Check the Red/Orange wire for power.
** 0V -- The relay is getting a ground from the bank angle sensor. At this point, the relay is getting everything it needs to operate and may be defective.
** 12V -- No ground from the bank angle sensor. Find out why.
***

3 -- Check for voltage at the Brown wire in the connector for the fuel pump relay for approx. 2 - 3 seconds after the key is turned on.
**** +12V -- The relay is providing power to the fuel pump. If the pump does not run, go to #4.
**** 0V -- Check for voltage at the Brown/Black wire in the connector for the fuel pump relay for approx. 2 - 3 seconds after the key is turned on.
**** Greater than 6 V -- There is insufficient ground from the ECU to activate the relay consistently. Possible poor connection or defective ECU.
**** Less than 3 V -- Normal reading. Cycle the key while holding the relay to feel for a click.
*** No click. The relay coil may be open. Replace the relay.
*** Click. Possible burned contacts. Replace the relay.
**** Between 3 and 6V -- Bad / intermittent connection between the relay and the ECU. Find and repair.
**

4 -- Tilt up the tank and find the fuel pump / low fuel 3 pin connector. Wrap a clean shop towel around the red jumper's sharp probe to prevent shorting it to ground then clip the red wire's alligator clip to power at the starter relay. Be careful with the probe: it is hot at all times. Leaving the connector plugged together, jump +12 volts to the Brown wire in the fuel pump connector. Do not apply battery voltage to the Brown/Black wire. It may damage the low fuel sensor in the tank.
**** Fuel pump runs -- Poor connection between the relay and the pump. Repair.
**** Pump does not run -- Leaving the jumper in place, ground the Green wire with the Black jumper. Make sure it is securely grounded to the frame.
**** Pump runs -- Defective ground. The main ground for the most of the electrical system is on the right side of the frame near the rear of the tank. Check this for a loose bolt or corrosion. Correct as necessary.
**** Pump does not run -- Defective pump, broken wire between the 3 pin connector and the pump, or gremlins. Replace the pump, repair the wiring, or have an exorcism done (or whatever it takes to get rid of gremlins).

This may all look intimidating, but if you take it one step at a time you'll probably find the problem.

Rob
Hey rob I know this is an old post, but I went to take a crack at this and right off the bat my pink wire is 0v. I tried jumping it from battery with another wire and nothing happens. Any help would be appreciated
 

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Old, Bold rider
2002 Honda 919, 1976 Yamaha XT500 cafe, TC-JAG TZ250
Joined
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2,480 Posts
Hey rob I know this is an old post, but I went to take a crack at this and right off the bat my pink wire is 0v. I tried jumping it from battery with another wire and nothing happens. Any help would be appreciated
If it was checked at the ECU and showed zero volts the next step is to remove the headlight and check the condition of the Pink wire at the four pole connector to the ignition switch, and if you can get to it the soldered attachment at the switch itself. If the wires and connections are intact the ignition switch (That's the electrical part.) is not making connection to the ~11 volt zener diode when the switch is turned on.

FYI: the ECU is looking for a voltage lower than the 12 volt system voltage. If system voltage is jumped to the pink wire it assumes it has been hotwired and shuts off the injectors, fuel pump relay, and ignition signals.

Good luck!

Rob
 
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