As the title says i am having something wrong with the area of the fuel pump. I am kind of stumped with this as is every one else who i have talked to. This is the scenario. The bike left me walking the other day so i decided to start taking it apart testing piece by piece. I checked the fuel filter and that is clean and has good flow. When i turn on the key the pump only pulses once.. Shooting out a pitiful stream of gas when i take it off the carbs. When I turn the bike over it does not put any more gas through it. I jumped the fuel pump from the battery and it pumped and worked fine. So i moved on to more electrical. I just replaced the fuel power relay (5pin) and that did not solve the solution either. I am at a loss here. I checked the 4 fuses under the cap and they were all fine. The battery tests out fine. What can it be?

I have done some reading and found there is one more relay called the fuel stop relay? Could it be this one that is causing it not to flow any fuel to the carbs?

Also when i am testing i am only putting the one hose back on the bottom of the tank that goes to the on off switch. I shouldn't have to hook everything else back up to test should i?

On a side note, hooking my tester into the jumper where the fuel pump plugs into the harness when you turn on the key it jumps to about 4 or 5 volts then when you turn over the engine i have nothing.

Any help would be appreciated.
Thank you in advance

 

Anything guys? Any help would be great.. I am tearing it fully apart this weekend. I am looking to take off all light and turn signal connections.. Can i leave them off while i test the pump to make sure it isn't a bad ground there killing the pump?

 

I'm struggling with a similar problem with you. I've been fighting mine for a few weeks.
My fuel pump did the same thing when I had the Transfer Relay jumped. I didn't do anything with the stop relay because the shop manual said to test the fuel pump by jumping the Transfer Relay and testing it's flow. You should get around 60 mL in five seconds which equals out to 700 mL in a minute. The shop manual said if the fuel pump didn't flow at least that amount with the relay jumped to replace it. So that's what I'm doing is replacing the fuel pump, I should have it by mid week next week.
As far as checking the ground, get a wiring diagram and see if the fuel pump shares a ground with the signals. What I would do is take the ground wire off and clean it up as well as the frame where it's bolted on and di-electric it. Then see what you have.

 

I will post you up with an update with what i run into this weekend.. i am replacing the batter too just for the thought of knowing that its been done. There isn't a tip over sensor on the F4's are there? If so where is it?

 

Got a new battery today and that wasn't it. (i needed one anyways) tested on the fuel stop relay and all three wires going in had 12 volts when the key was turned on. Is it suppose to be like this? Like i said i just replaced the fuel pump relay. Could this still be the pump? It still only pulses once when i turn on the key and it does not pulse any more after that. I took off all connections (turn signals lights front and back to make sure it wasn't anything bad that i have put on it. I would like to wait to see if its the fuel pump on yours cbrf4bp before i go to any more steps.

 

I too did some testing on mine today following the flow charts in the Honda Service manual (the actual Honda one, not Haynes, I got off the forum here) just to see if I could get any different results or different tests than the shop manual I was using. I still came up with the fuel pump being bad, the fuel pump transfer relay, the fuel stop relay, and everything else associated with the fuel system tested fine.
I would say to check your flow rate on your fuel pump if you haven't already by jumping the transfer relay.
Also I couldn't find any sort of tip over sensor in the wiring diagrams so I don't think that there is one.

 

Thanks man... I debating in ordering a pump for it or just taking it to the shop on Tuesday.. i would hate to pay for a pump and have it not be it... I guess i could always sell it later huh? This whole thing of not being able to ride has got me down..

 

Are you tried to remove plastic cap from pump and clean contact with electronic spray?

 

Cleaning the contacts is a good idea, I'll probably try that in a little bit here. Anything's worth a shot right now.
yog182: have you tried testing your flow rate? The way I'm thinking is that I've done all the other tests to ensure that everything that effects the fuel pump is good, so all that's left is the fuel pump. I found the downloadable Honda Tech manual/Service Manual to be invaluable. It has awesome flow charts for troubleshooting the fuel pump system. It's on here in the F4 forum if you're interested and have time to run through the tests.

 

Yes all has been tested.. The whole month of not riding has made me crazy and making me look at other bikes... Eventually turning this one into a stunt bike. Just looked at a 636 today.. Checking insurance tomorrow.. Probably pick it up the end of the week. I would still like to know your outcome of the new fuel pump to give me some inspiration for mine =)