Honda XRV Forum banner

1 - 8 of 8 Posts

·
Space Emperor
Joined
·
655 Posts
Discussion Starter · #1 · (Edited)
OK, this is weird and I'm not very good with electrics, so desperately need some help!

The Facet fuel pump on my RD07a doesn't run. BUT if connected directly to the battery, it runs fine.

The battery is fairly new, and measures 12.8v, engine off. All bike electrics run fine, and bike runs fine on gravity feed.

Measuring the harness wires going to the pump, but pump not connected, it shows:
  • 0v when the ignition is off
  • 11.5v when ignition is on, engine off (this should be 0v ??)
  • 12.4v with engine idling
  • 12.8v with the pump connected and engine idling

Resistance between pump harness wires is 0.9, and the same for black wire to frame. Red wire to frame is 0.

What's going on here? It seems to me that if I can measure 12.8v on the wires when the pump is connected, it should run???

What's the next step? Fuel cut-off relay? I'm at a loss ...
 

·
Space Emperor
Joined
·
655 Posts
Discussion Starter · #2 ·
If bypassing the relay, which wires should I bridge?
166251
 

·
Registered
Joined
·
2 Posts
If bypassing the relay, which wires should I bridge?
View attachment 166251
if you want to bypass icu, the blue with yellow wire come from icu, so to bypass relay need to connect two others. I dont have rd07a, but checked on wiring diagram.
My english is bad, but I try to ask... this problem was started suddenly or that was all the time you have this motorcycle? If that was all the time, the is a chance that somebody messed up wires after cleaning or what, because on wiring diagram blue one with yellow is in middle.
 

·
Junior
Joined
·
473 Posts
Showing voltage that don't mean it could carry amps, connect halogen buld to wire ends at pump and see if it lights up if not yiu need to trace could be partly broke wire or bad ground

Sent from my G3121 using Tapatalk
 

·
Space Emperor
Joined
·
655 Posts
Discussion Starter · #6 ·
Thanks for the help guys!

GSPD750, that post is more or less what I've been through! But it gets more complicated:

OK, so I managed to solve the problem yesterday, after having measured and measured again, following Haynes. The culprit was indeed the fuel relay, but the reason why I didn't register this right away was that somehow - and I can't really imagine how this came about - the wires going to the pump has been reversed! I had connected red to red and black to black all along, but noticed that it was a negative current. With the cut-off relay bypassed and the polarity switched, it ran once again.

I haven't been out for a ride yet, but the pump is humming nicely when I turn the key. I let her idle for 5min, and there was no hiccups. I will go 50 times around the block tonight, to see if all is well.

Going through the harness to find bad plugs (found 3!!!) I've been cutting off some plugs and soldering the wires, after seeing that the plastics were slightly melted due to bad contact. Also, what I believe was the fuel pump wire, running between the tank and the battery was worn from rubbing, so I soldered that too. I guess somehow I must have reverse two leads somewhere?

Or is the relay not working due to reverse polarity?

I'm tired, and just want to ride. If the bike rides OK tonight, I'll leave it like that for a while, and then maybe at some point go back and check those wires I soldered.
 

·
Space Emperor
Joined
·
655 Posts
Discussion Starter · #7 ·
if you want to bypass icu, the blue with yellow wire come from icu, so to bypass relay need to connect two others. I dont have rd07a, but checked on wiring diagram.
My english is bad, but I try to ask... this problem was started suddenly or that was all the time you have this motorcycle? If that was all the time, the is a chance that somebody messed up wires after cleaning or what, because on wiring diagram blue one with yellow is in middle.
Yes, I noticed that! But I figured that the diagram might be for a different model or Haynes just got it wrong.

I reckon that the whole thing was a mix of faults, going from gummed up carbs from bad Vietnamese gas, to bad plugs getting hot, and a relay that was probably packing it in. Anyway, feels good to have had a check through those things, and sorted them out
 

·
Space Emperor
Joined
·
655 Posts
Discussion Starter · #8 ·
Showing voltage that don't mean it could carry amps, connect halogen buld to wire ends at pump and see if it lights up if not yiu need to trace could be partly broke wire or bad ground

Sent from my G3121 using Tapatalk
I did check for continuity, like the manual suggests, and all was fine, but it still didn't run. That's when I noticed that the leads to the pump showed negative current. Grrrr!
 
1 - 8 of 8 Posts
Top