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Fuel Pump Not Priming

30K views 54 replies 8 participants last post by  Wingnutsrc51 
#1 ·
Whats up everyone. I am having issues with the fuel pump not priming. I have checked almost all the threads on here that has to do with it and I have tried almost everything to try to fix the problem. Ill just start with what had happend to bring me to this issue.

I had put a PC3r on my Rc and it was popping even with the correct map. Shortly after installing the PC3r, I was having issues with keeping the motorcycle running for longer than 10 seconds. Thinking that it was a filter issue, I decided to change out the filter on the bike. Still I was having the same issues. I then thought that it was the power commander so I removed it until I was able to bring the bike to a shop to have the PC3r fine tuned. The bike went back to running as normal. Just to be sure, I went and took it for a quick spin around the block. I didnt even make it 200 yards and the bike just shut off. I noticed that no fuel was priming. I also heard the normal click that you would hear as well coming from the back of the tail. The click I am assuming is coming from the bank angle sensor.

Since then, I have swapped out my headlight relay with the bank angle sensor as well as the fuel cut off relay. I am still havint the same click within the tail. I check out the bank angle sensor and visually, it seems good as well. No matter what relay I change out and put in the fuel cut off or the bank angle relay, I know that the relay that I am swapping them with is working because I know my hi beam goes on.

Any help that you guys can prive would be awesome. It seems I have spent more time fixing this bike than riding it. let me know your thoughts. Thaks fellas.

Vince
 
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#2 ·
Since your relays seems to work fine, you should also check the kill switch's wiring.
That switch kills the current flow to the starter relay from which the pump's relay is powered from.
That's why, when you have your kill switch to RUN position, turning the main switch on, you can hear you pump working for a couple of secs, but if your kill switch is in OFF position, you don't.
 
#3 ·
These kill switches have also been known to fail due to corrosion from the weather.
This is why I always push the dielectric grease for all electrical contacts.

We used to use this stuff in the Navy when splicing guidance wires on the torpedos.
Also the auto manufacturers make it a requirement for electrical connectors as well.
 
#4 · (Edited)
Absolutely true that is the best solution.....next best thing to that, is lots of WD-40 (penetrating oil) through the gash around the switch and through the draining holes underneath, working it on and off ten times, at every oil change. After all that switch is there to save our limbs in a difficult situation
 
#5 ·
Electrical contact cleaner spray works well too. Just be sure to protect the nearby areas as it can be hell on painted surfaces. A good shot from a can of compressed air afterwards is also a good idea, gets left-over residue out. Wear safety glasses too.
 
#6 ·
Ill check out the kill switch and clean it up a bit. However, as I had mentioned, the bike just shut off for no apparant reason while I was riding. I had a full tank of gasoline as well. Since it turned off, that is when I reached the problem with pump not priming. I will check the switch though and put the grease on all my connectors. Ill get back here shortly.
 
#7 ·
Ok well I looked at the cut off switch and the copper areas inside the switch do not look to be corroded at all. The switch toggles back and forth with no issues and it appears clean inside the casing as well. I didnt put any grease on the switch since the switch itself has plastic covering it inside of the casing. Any other ideas that you guys can think of?
 
#9 ·
Ok fellas this will be my last post tonight. let me know what you think I should do next. Ill check tommorrow.

I found out that my fuel pump is working just fine. I jumped the fuel tank connectors directly to the battery. I lookedat and cleaned the cut off switch, and again tested the BAS and Fuel cut off relay with the working hi beam relay. All looked good. I am still stumped and I want to actually ride this beast rather than just work on it. I hope one of you can come up with something that will be the problem tomorrow. Thanks fellas.
 
#10 ·
On the surface, it sounds like you may have a broken wire somewhere.
Were you careful to not pinch the wire harness while raising and lowering the fuel tank?
This is often what happens if the harness gets pinched between the tank an frame.

The relays sound like they check out for operation as well as the engine stop switch.
So I suggest obtaining a decent digital volt-ohmmeter and the wiring diagram and start checking for broken wires in the fuel pump power path.
 
#11 · (Edited)
I'm pretty sure that the connector for the fuel pump runs underneath the tank. So he has at least eliminated that section of wiring if he jumped the pump there.

The relay is working, the pump is working, it has to be between them.

I would take the tail off and have a good look at all the wires on the left side of the subframe. There is a very fat bundle of wires running along the subframe and around various brackets that can easily rub through the wires. Also have a good look at your grounds.

Also when you say "it just shut off", do you mean the engine stopped running? Or the whole bike, lights and dash and everything?
 
#12 ·
I would do the folowing but at my own risk (and make sure you don't mix up any connector mentioned below.)
First make sure that the harness is in all places pluged on (like when you ride the bike).
Unplug the ECM (that way ther is no way you can damage it).
Turn the key to ON and kill switch to RUN position.
Take a piece of wire and connect it securly on the (+) side of the battery and its other end plug it firmly in the B2 slot (ECM's grey connector) where a Black wire with a white stripe ends up.
Then take another piece of wire and hooking its one end on the (-) side of the battery, plug its free end in the A8 slot (ECM's Black connector) where a Brown wire with a black stripe ends up.
If you hear your fuel pump priming retract the last mentioned cable. Your pump circuit is OK and ther is no problem with it.
 
#13 ·
When the bike shut off, it was just the engine. All the lights were there and functioning properly. When I tried to restart it, it would turn but would not complete. It was wen I turned the bike off along with the kill switch and ran through the normal motions of starting a bike that i descovered that the pump was not priming.

I did no a lot of movement with the wires today so I will definitely have to look at them. When I got the bike, it was a mess of spaghetti wires every place. The previous owner made a hack job of it. It took me a long time to trace the wires in the tail section becaus there was no relays at first. Sub assisted me with the wiring a long time ago.

I will start looking at the wiring Now and let you guys know.
 
#14 ·
If the harness was a mess, it would be easier for you to find a used rear half of the harness on ebay and replace it than to try to make one out of the spagetti on your own.
Have that said, take a close look on the wiring diagrams in the service manual and you will see that both bank angle's relay and fuel pump's relay have a common wire (black with white stripe) that delivers them the (+) from the ECM to function. Without it they cannot be engaged. That is why I recommended to try engaging them manualy pretending to be the ECM. That way you can tell if the main body of the harness still does it's job.
Be patient with the electrical repairs and any question you have, please share it
 
#15 ·
The harness was pretty much all there except for the relays. All the relays were cut off. When I bought the bike, it was set up for racing. I had to build it to make it street legal again. All I had to do as far as the harness was figure out what wires were what relays. Since the lighting was all cut up, I was planning on putting in an undertail so it made my job easier. Sub helped me with that area a while ago.

I have never tested wires before with a voltometer. I am pretty mechanicaly enclined so I know I can do this as well. I just dont know how to start testing wires. let me know exactly how to do it and what the volts should read. I am sure that if I am testing a positive battery, then it will read 12v and if it is a negative, it should read 0 right? let me know guys when you have a moment.
 
#16 ·
Basicaly you don't really need a voltmeter. You need a test tool that can tell you that you do have or not a current (live cable). That tool is like a screw driver with a 12V bulb in it that has a 12 inch wire with clamp on one end and a sharp tip on the other. That way you can tell if a cable is "live" while it's cable end is hooked on the ground, or if a cable is ground while it's clamp is hooked on the battery's (+).
But you should start reading an electical diagram first. The cables colors can help you a lot to start.
Are we talking about SP1 or SP2 bike?
 
#18 ·
Ok so I am pretty much testing the wires just like I tested to see if the pump worked. On the fuel pump, I put the negative wire to the negative terminal and positive wire to positive terminal? The wires I used were the ones that come directly from the tank itself.
 
#19 ·
Ok guys, I was checking out the wires on the bike. I noticed that on the sub harness where the grey connector is, the black and white wire is cut. So in other words, the sub harness black/white wire is cut down the middle making an open wire that goes to the grey connector to the ECU. Is this a bad thiing? Could I have blown the ECU due to this? I am still checking out the wires because I dont know if this is the issue yet. Let me know your thoughts.
 
#21 ·
MAKISRC51, I did as you said in regards to unplugging my ECu and connecting a lead from the positive terminal to the black/white wire on the grey connector and a lead from the negative terminal to the brown/black wire on the black connector. My fuel pump turned on so I know know that my pump circuit is fine. I am still stuck with this problem though. Any thoughts.
 
#23 ·
Ok....Before we say for sure that you need to replace the ECM, try something else.
With the ECM off the harness, switch on the key and the kill switch to RUN position and check the B18 pin (Grey Connector), which is a Green/Red stripe cable, against the (-) battery's terminal. You should see 12V or the light on the test tool should go on.
If that is ok, the hook the test tools clamp on the batteriy's (+) terminal and test the following cables
1) A10 (Black Connector) Green/Pink stripe cable
2) A11(Black Connector) Green cable
If both are "live" againts battery's possitive terminal, then most likely you have to replace your ECM.

You can download the SP2 electric diagram from here if you need to (it will only be available for the next 10 days).
P.S. the test tool I am referring to is something like this

and you can get it off eBay very cheap.
 
#22 · (Edited)
The signal to to actuate the fuel cut-off relay comes from A8 of the ECU.
Since you've tested the operation from that point on, and it caused the fuel pump to operate, then it is possible the ECU may be bad, or not making good electrical contact.

If you reinstall the ECU and pull the fuel cut-off relay, you see a signal at the Br/Bl wire when the key is switched on.
 
#26 ·
The Black/White cable is (+) but not going towards the ECM but FROM the ECM to power: angle sensor relay, fuel cut off relay, pair valve relay, flapper valve relay, injectors and radiator fans relay. The ECM gives a constant current through that Black/White wire and then control them with their "ground" (I use "" cause it isn't actually ground but a returning current to the ECM)

However, in order to power up the ECM so that it can give power to the Bl/W cable, the last test I described you must come out possitive. You should have live battery (+) to the G/R cable and live ground to the other two.
If everything works as I described then you need to replace the ECM. Cause that would mean that it is powered normally but still not engaging the fuel pump relay, the way you engaged it manualy.
Take your time my friend......current is for patient people. :D
 
#27 ·
I have not got around to getting the probe to test the circuits today. I am going to do that first thing tomorrow. In a way, I hope that the ECM is bad so that I can end this issue and actually ride my bike. Well see tomorrow. Ill check back in and let you guys know. Thanks.
 
#29 ·
Ok I have tested the conectors with the probe. The green/red wire on the grey connector does not light up when touched. On the black connector, there are two pink/green wires on that connector. One pink/green wire lights up when touched. The other pink/green wire does not light up as well. The green wire on the black connector when touched will not light up as well. Just to make sure that I am testing the correct wires, I have the bike turned on and the kill switch in the run position. The probe is on the negative terminal on the battery. I was also testing the wires on the subharness connectors, not the ECM. I am still stumped on this and I was hoping that the ECM was going to be the problem. What else do you think that it could be?
 
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