Have voltage but fuel pump doesn't run?

[thrstrmech]

the fuel pump circuit: pump to ecm (fuel pump output), pump to ground (shared ground with multiple components), pump to ignition (shared with coil/ecm/injectors/data link), pump to instrument panel (low fuel warning) all this looking at the wiring diagram from my '03 9S...this should be the same as to what is connected to what to complete the circuit.

 

[July4]

Ok, I'm still baffled as to why the pump doesn't run if the meter shows 11.7V I'm stuck on the fact that both the old pump and the new will run off the battery and not of the harness with 11.7V. Can any one shed some light on that?

 

[thrstrmech]

have you checked the ignition switch, wiggle test it? turn key on and wiggle the connector/harness see what happens? wiggle test from the pump side connector/harness?

 

[July4]

Yes but without the wiggle. WIll do

 

[Shawns]

When you check for voltage for the pump, are you checking using the battery as ground or the ground in the connector. If it is a ground trigger at the pump and thats not turning on then that would be the issue. If it is 12v and you don't have the ground....same issue. Even tho your relays check good, somewhere down the line you might have a break in a wire. If you have the manual check the EVTM part and trace down your wires.

 

[July4]

Whats EVTM?
Yes, I seem to remember thinking the housing needed to be grounded and tried grounding it with no result. But there is a plus and minus wire. Either way, I'm going to go check it again. I'm desperate for an answer! I spent half the day trimming ******* trees today!

 

[July4]

EVTM = wiring diagram. I see now. Grounding the pump body to the frame yielded no improvement. I'd still like some insight on why these pumps will not turn over with 11.7V? Still makes no sense to me.

 

[Chicknstripn]

Man, I know you're frustrated. But it's awesome that you're tackling the trouble shooting yourself. It's never easy when you're going down uncharted mechanical/trouble shooting territory.
When this chapter in your book of Buell is finished it will all be worth it.
BTW have you checked the ignition wires at the key switch? You mentioned something was obstructing full lock in one direction.
Also, have you checked the inside of the kill switch and the associated wiring?
Good luck man!
Oh and that tree trimming comment had me literally laughing out loud. I feel your pain there. I spent all day weeding an effing garden!

 

[July4]

Checked the Kill switch, looks perfect and seems to work fine. Checked continuity at the ignition switch and it seems to work fine. Didn't do the wiggle test yet, but everything in there looks pristine; will do it anyway when I get home. I think I'm missing something really really basic, I just don't know what. The ignition lock pin does not appear to come out far enough to lock with anything. Doesn't cause any problems, it just doesn't work.
At times I have felt as frustrated as Steve Martin in planes trains and automobiles when he curses out the lady at the rental counter. F this, F that etc. funny scene about someone who is frustrated.

 

[rchuff]

Continuity test is not always the best test because you might have only two thin strands of wire in the casing still connected and the rest are broken witch will lead you to think it is ok but it is not.

 

[July4]

I agree, cause that what it seems like. So how else do you test? two strands can still carry 12V. I don't know how to put a load on it other than the pump, which is not running. I feel like I'm going in circles.

 

[rchuff]

You should ohm the wire with your multi-meter and then wiggle that wire in different spots and if the numbers start going all over the place (meaning up or down ) then you found your problem. I said this in my earlier post on page one.

 

[July4]

Last night I don't think my ass hit the seat of my wheeled swivel stool next to the bike before I heard my wife coming in the gate. Damn! No time to work on it. I did manage to do a quick test that yielded some result. I bi-passed both the hot lead and the ground lead one at a time to see which side the problem was on and it is the ground side. So now at least I know I'm chasing after a problem in the Brown / yellow wire! Progress! Yes, I could have done this a lot sooner. Yes I seem to suck at electrical trouble shooting. I will probably be utilizing your wiggle test you mentioned on page one now. Hey, it's just taking me some time to warm up to this. I will say I did find a few things that would have definitely become problems, like those wires that were worn 1/2 through. and I do understand the system better for what that is worth. So far the biggest issues seem to be from wires getting their insulation rubbed through.

 

[thrstrmech]

break out the wiring diagram and trace the wire. anything else share that wire?

 

[July4]

Nope, looks like it goes straight from the pump to the ECM. That worries me. I did find a spot where the wire was worn through, but I fixed it with a splicer and things didn't improve. So I can test the ohms for that wire and the ground wires (a&b) coming from the ECM, but that is it. It just doesn't seem likely that I will find something else since I've been looking at that part of the harness pretty closely already. I've read where people have had a bad pin connection, so I'm going to be looking for that sort of thing. I will dive into it after work today. Someone pray to the gods of poor grounding. (I'm guessing they all wear Lucas T shirts).

I do have a real question. Does this pump have a voltage cutoff where it will not run on any less than 12 V? Some systems will not allow things to operate if you are even a tenth under 12V.