Fuel cut-off relay issue - Honda RC51 Forum : RC51 Motorcycle Forums
 
LinkBack Thread Tools Display Modes
post #1 of 7 (permalink) Old 07-06-2013, 05:28 PM Thread Starter
Senior Member
 
jondog9's Avatar
 
Join Date: Aug 2010
Location: Northern CA
Posts: 8,653
Mentioned: 15 Post(s)
Quoted: 317 Post(s)
Fuel cut-off relay issue

My fuel pump prime cuts out intermittently. The bike wont start.
What it's doing: When I turn the key on, I hear and feel the relay clicking.
What I've done: 1st, swapped in my known good headlight relay. Same thing.
2nd, unplugged the relay from the socket and inspected the wiring - seems to look sound. (I've previously treated it with dielectric grease)
The wiring is burried in the rear harness, until it emerges as a 3P black connector. I inspected that connection as well. followed the wiring to the underside of the tank and it seems to check out visually as well.

I'm refering to the manual now to figure out what to do next.
It appears I'm not getting reliable power up to the solonoid to get it to throw power to prime the pump.
This only happens when trying to start. Of the threee times now it's happened, I cycle the key a couple times and then she primes. Doesn't cut out once the engine is running. Yet.

Anyone have any advice what to test next?

John, 2000 RC51 #000100

jondog9 is offline  
Sponsored Links
Advertisement
 
post #2 of 7 (permalink) Old 07-06-2013, 06:31 PM
Senior Member
 
Join Date: Jun 2013
Location: Glasgow, Scotland
Posts: 162
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by jondog9 View Post
My fuel pump prime cuts out intermittently. The bike wont start.
What it's doing: When I turn the key on, I hear and feel the relay clicking.
What I've done: 1st, swapped in my known good headlight relay. Same thing.
2nd, unplugged the relay from the socket and inspected the wiring - seems to look sound. (I've previously treated it with dielectric grease)
The wiring is burried in the rear harness, until it emerges as a 3P black connector. I inspected that connection as well. followed the wiring to the underside of the tank and it seems to check out visually as well.

I'm refering to the manual now to figure out what to do next.
It appears I'm not getting reliable power up to the solonoid to get it to throw power to prime the pump.
This only happens when trying to start. Of the threee times now it's happened, I cycle the key a couple times and then she primes. Doesn't cut out once the engine is running. Yet.

Anyone have any advice what to test next?
Are you reliably getting voltage to the 3p Connector attached to the fuel pump? should only get if for a few seconds after ignition switched on
weegaz22 is offline  
post #3 of 7 (permalink) Old 07-06-2013, 07:55 PM Thread Starter
Senior Member
 
jondog9's Avatar
 
Join Date: Aug 2010
Location: Northern CA
Posts: 8,653
Mentioned: 15 Post(s)
Quoted: 317 Post(s)
Quote:
Originally Posted by weegaz22 View Post
Are you reliably getting voltage to the 3p Connector attached to the fuel pump? should only get if for a few seconds after ignition switched on
I didn't check there. since the relay itself is buzzing, even when I swap in a known good one, I figure the problem is before that.

So I tested the brn/blk wire with the relay unplugged. According to the manual, that wire leads to pin 8 on the ECM. It provides that momentary power to prime the pump. Key on, no power at all. So that's a problem.
Next looked at the wiring diagram again, and saw the Bank Angle relay shares the blk/wht wire. Wondering if this is a common ground, it runs to pin 2 on the ECM.
Then I wondered if swapping the bank angle relay for a known good one would do the trick.
So I did, and PrestoWellahhhh! _PumpPrime_ every time I cycle the key. both relays (fuel cut-bank angle) click good and strong when I turn the key on.

So does this make sense, or is it coincidence and my problem may come back?

John, 2000 RC51 #000100

jondog9 is offline  
 
post #4 of 7 (permalink) Old 07-07-2013, 02:57 AM
Lifetime Premium
 
MakisRC51's Avatar
 
Join Date: Jan 2012
Location: Korinthos, Greece
Posts: 3,239
Mentioned: 15 Post(s)
Quoted: 77 Post(s)
The Bl/W wire is not a ground. It's a +

If you remove the 30A fuse on the Battery, with the solo red wire, you'll see that it will die.

As you describe it, sounds like a faulty relay. I don't think it'll happen any time soon.

Even if it does, you'll know where to look first.

The Black/White wire is the power source for ECU, fuel injectors, air duct solenoid valve and the spark converter unit box. And all that is ON and OFF through the Bank Angle Sensor relay.
So if you lean the bike, everything shuts down.


My Íhlins Project: https://www.rc51forums.com/forums/showthread.php?t=6033
Quote:
Originally Posted by SubSailor View Post
Congratulation to MakisRC51 for winning the 2014 Bike Of The Year Contest!
MakisRC51 is offline  
post #5 of 7 (permalink) Old 07-07-2013, 01:51 PM Thread Starter
Senior Member
 
jondog9's Avatar
 
Join Date: Aug 2010
Location: Northern CA
Posts: 8,653
Mentioned: 15 Post(s)
Quoted: 317 Post(s)
Thanks Makis, I saw how that Bl/W wire went to all the components you listed.
Yes, I agree, I seem to have had a bad bank angle relay.
That wasn't exactly my first line of reasoning, but I know both of them are integral to the pump priming before startup, so it was kind of a lucky find.

John, 2000 RC51 #000100

jondog9 is offline  
post #6 of 7 (permalink) Old 07-07-2013, 01:58 PM
Lifetime Premium
 
CapeCodderRC's Avatar
 
Join Date: Jul 2012
Location: Cape Cod Massachusetts
Posts: 1,239
Mentioned: 6 Post(s)
Quoted: 114 Post(s)
Garage
This site is awesome . Sorry to hear of your problem Jon, but you and Makis , Weeg ,sure have helped others here , who may encounter your problem with their own bike at some point . Good diagnostics . Glad you got her running

Growing old is mandatory , Growing up is Optional
BOTM / April 2014 , October 2016
Clint / 2000 RC51 #414
CapeCodderRC is offline  
post #7 of 7 (permalink) Old 07-07-2013, 02:43 PM
Lifetime Premium
 
MakisRC51's Avatar
 
Join Date: Jan 2012
Location: Korinthos, Greece
Posts: 3,239
Mentioned: 15 Post(s)
Quoted: 77 Post(s)
Quote:
Originally Posted by CapeCodderRC View Post
This site is awesome . Sorry to hear of your problem Jon, but you and Makis , Weeg ,sure have helped others here , who may encounter your problem with their own bike at some point . Good diagnostics . Glad you got her running
My good friend, I can seriously tell you that there are a lot of time that I see things I can say a word, but working out my technical english and lay them down to a web page is so difficult that I prefer just not to participate......and I am sorry about that....seriously!

I have been a vehicle's electrician/ electronic (that's my degree's title actually) since 1997.
Never said I know everything, especially the newer bikes which I can't follow anymore since I've left the workshop business and working as a driver.

But I love my job so I try to follow up the technology as much as I can.

Of course I am wrong many times......it isn't that easy to diagnose a problem through a screen and a keyboard.

I am lucky that I have found this beautiful company of RC51 fans and i am really sorry that I can't offer more.....I really am


My Íhlins Project: https://www.rc51forums.com/forums/showthread.php?t=6033
Quote:
Originally Posted by SubSailor View Post
Congratulation to MakisRC51 for winning the 2014 Bike Of The Year Contest!
MakisRC51 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Honda RC51 Forum : RC51 Motorcycle Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome