Member Contributer Captain 80s Posted May 22, 2020 Member Contributer Share Posted May 22, 2020 2003 VFR, 30K miles. Bike was dropped and wouldn't start after previous owner tried to put it back together. Cranks over good with no weird sounds. Looks like the ignition switch and fuel cap have been replaced with aftermarket, which had me kinda nervous, and makes me think we didn't get the whole story. Scorpion slip-ons, PCIII, decent Avon tyres, Helibars, brakes and rotors excellent, replacement fairing kit that doesn't really look that bad. Decided we would roll the dice at $1000. I knew I should hear the pump prime when turned on and it didn't. After checking all the simple stuff (good battery, kill switch, side stand switch, fuel in tank, loose connectors) found the fuel cut relay and bypassed it, and we had power to the pump. Re-connected the plug to the pump and it lit up. Thought we had it! But, the fuel pump whines and doesn't stop. Just doesn't seem like it's actually pumping anything to build pressure. It is definitely under fuel. The kill switch will stop and start the pump and the FI light goes on and off accordingly. Oh, and we gave it a few good smacks with wood dowel too while it was "running". That sounds like a bad fuel pump, eh? Contemplating buying a cheap shitty pump just to verify and sort the rest of the bike before buying a good one. Link to comment Share on other sites More sharing options...
Member Contributer BusyLittleShop Posted May 22, 2020 Member Contributer Share Posted May 22, 2020 Basic understanding of fuel pumps... the pump doesn't build pressure... the pressure relief valve (10) builds pressure... if the pressure relief valve offers no resistance then fuel circulates from pump back to the tank at 0 psi... Link to comment Share on other sites More sharing options...
Member Contributer Grum Posted May 24, 2020 Member Contributer Share Posted May 24, 2020 On 23 May 2020 at 1:22 AM, Captain 80s said: 2003 VFR, 30K miles. Bike was dropped and wouldn't start after previous owner tried to put it back together. Cranks over good with no weird sounds. Looks like the ignition switch and fuel cap have been replaced with aftermarket, which had me kinda nervous, and makes me think we didn't get the whole story. Scorpion slip-ons, PCIII, decent Avon tyres, Helibars, brakes and rotors excellent, replacement fairing kit that doesn't really look that bad. Decided we would roll the dice at $1000. I knew I should hear the pump prime when turned on and it didn't. After checking all the simple stuff (good battery, kill switch, side stand switch, fuel in tank, loose connectors) found the fuel cut relay and bypassed it, and we had power to the pump. Re-connected the plug to the pump and it lit up. Thought we had it! But, the fuel pump whines and doesn't stop. Just doesn't seem like it's actually pumping anything to build pressure. It is definitely under fuel. The kill switch will stop and start the pump and the FI light goes on and off accordingly. Oh, and we gave it a few good smacks with wood dowel too while it was "running". That sounds like a bad fuel pump, eh? Contemplating buying a cheap shitty pump just to verify and sort the rest of the bike before buying a good one. If you've bypassed the Fuel Cut Relay, then it will run continuously. The ECM controls the relay coil switching Ground so if you were not hearing the 2 second prime at switch on (Kill Switch to RUN) with the relay installed then the relay, ECM or wiring could be at fault. The Service Manual shows how to check the Fuel Pump for flow. I wouldn't assume you have a Fuel Pump issue without checking it's flow first. Once you're happy with the Fuel Pump and the switch ON prime function is working, but it still doesn't start, then perhaps the Ignition Enable logic for the ECM may need checking, this relies on Neutral and Sidestand switch logic. With the Fuel Cut Relay installed and listening closely at the relay, Ignition to ON, Kill Switch to RUN, do you hear it click on then off after two seconds? This should happen irrespective of your Fuel Pump status. This drawing might be easier to see how the Fuel Pump is powered. Link to comment Share on other sites More sharing options...
Member Contributer Captain 80s Posted May 24, 2020 Author Member Contributer Share Posted May 24, 2020 On 5/22/2020 at 12:16 PM, BusyLittleShop said: Basic understanding of fuel pumps... the pump doesn't build pressure... the pressure relief valve (10) builds pressure... if the pressure relief valve offers no resistance then fuel circulates from pump back to the tank at 0 psi... Thank you. I was just so used to the pumps on my other bikes that actually do build pressure. Not long after posting I thought about the return line and realized my error. Link to comment Share on other sites More sharing options...
Member Contributer Captain 80s Posted May 24, 2020 Author Member Contributer Share Posted May 24, 2020 10 hours ago, Grum said: If you've bypassed the Fuel Cut Relay, then it will run continuously. The ECM controls the relay coil switching Ground so if you were not hearing the 2 second prime at switch on (Kill Switch to RUN) with the relay installed then the relay, ECM or wiring could be at fault. The Service Manual shows how to check the Fuel Pump for flow. I wouldn't assume you have a Fuel Pump issue without checking it's flow first. Once you're happy with the Fuel Pump and the switch ON prime function is working, but it still doesn't start, then perhaps the Ignition Enable logic for the ECM may need checking, this relies on Neutral and Sidestand switch logic. With the Fuel Cut Relay installed and listening closely at the relay, Ignition to ON, Kill Switch to RUN, do you hear it click on then off after two seconds? This should happen irrespective of your Fuel Pump status. This drawing might be easier to see how the Fuel Pump is powered. Thank you very much. I will check some more items. Sidestand and kill switch are operating normally and Bank Angle Sensor is new.. Don't think I have heard a click, but I will check closer. Link to comment Share on other sites More sharing options...
Member Contributer Captain 80s Posted May 29, 2020 Author Member Contributer Share Posted May 29, 2020 It now primes properly (2 seconds) and has spark. Turned out to be 2 things. An aftermarket ignition switch (brand new installed by PO) that wasn't routing power properly. It would make the main connection (red + red/black), but it wasn't supplying power to the other 2 wires (weird). After a combination of a couple jumper wires, still nothing. Fuck. Swapped out the FCR with the High Beam Relay (AGAIN!) and it primed for 2 seconds. Checked for spark... Yes! This is going to be a pretty fucking nice $1000 2003 VFR. I'll post some pics when I get it back together. Thank you for the responses and suggestions. Link to comment Share on other sites More sharing options...
Member Contributer raYzerman Posted May 29, 2020 Member Contributer Share Posted May 29, 2020 That ignition switch screwed you right up..... you got this now! BTW, good deal. Link to comment Share on other sites More sharing options...
Member Contributer Captain 80s Posted June 7, 2020 Author Member Contributer Share Posted June 7, 2020 New air filter arrived and installed (mouse nest had to be cleaned out). Bike fired instantly. Rolled outside and let it run until thermostat opened and fan kicked on and off. Runs pretty much perfect. Rode it to a buddy's. Pulls pretty damn hard, the PCIII seems to be fairly dialed in. Brakes feel really good. Exhaust sounds nice but not obnoxious. Needs a front turn signal bulb (running light) and a front brake switch (WD40 didn't help). So..... probably a $1050 2003 VFR then. Not bad. Link to comment Share on other sites More sharing options...
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