| Author | Message | ||
     Fantic97 |
So recently I have replaced my fuel pump (with oem). and that solved my CEL and fuel pressure issues. Today about 800 miles after fuel pump replacement I heard my pump cycle after bike was off which it only did right before my fuel pump went out. When I got home I checked in DIAG and fuel pressure would not hold and went from 4xx kpa to into the 2xx kpa within a minute with bike off. With bike running it holds a steady 410ish kpa. My question is what now lol? A injector sticking or weeping? Im not leaning towards regulator as pressure is fine running? Any ideas? Can you test the injectors? | ||
| Dannybuell |
when the engine is off pressure is maintained in the fuel rail to avoid the vapor lock that can occur with a heat soaked engine. I hope this helps. | ||
| Fantic97 |
No I get that. Pressure slowly drifts lower with engine off. It is ok while running. Sometimes drifts lower faster than other times. Want to know if this is acceptable or what could be the cause? | ||
| Two_seasons |
Ride it, worry later when it won't run! | ||
| Stevel |
Fuel injectors can be easily tested off the bike. You will have to make a little simple fixture to do this though. You need a fuel supply of about 50 PSI and the easiest way is to make a small canister out of a piece of exhaust tubing with a spigot on one end for the fuel line and a tire valve on the other. This you charge with a hand tire pump to 50 PSI when the canister is half full of fuel. Do not use a simple bottle or sheet metal fuel tank, they will likely burst with 50 PSI! The biggest issue is the fuel line fitting. They are made by NORMA. They are called NORMA Quick S fittings and the hose is called NORMAFLEX. The fittings are really good. The spigots are fitted with an "O" ring that seal against a special nylon liner inside the hose. The line and spigot is heat shrunk together and do not require a clamp. The problem is that these components are NOT sold outside of OEMs. The minimum order quantity is 100 pieces. (see the Norma Group web site for photos) So they are unobtainable to us. But for the test rig, normal 5/16 fuel hose and two hose clamps per end can be used. Another issue is that the electrical connector appears to be a non-standard one and I have yet to find a source, but a you can use a couple of pieces of squished tubing soldered together with a wire lead and a momentary switch for a quick connection to a 12V battery. Once everything is rigged together, there should be no leaks anywhere. With a quick depression of the switch you should see an even stream of fuel through each hole of the injector equal to each other. Immediately after lifting the switch button, the fuel should sharply stop with no dripping. If this simple test passes, your injector is good to go. | ||
| Captjoe |
I'm confused.... So when the engine is running, the pressure is good. When the engine is off, the fuel pressure goes down. What's the problem here? I'd be worried if the engine was on and the fuel pressure was going down. Am I missing something? | ||
| Dannybuell |
my guess: As the engine temperature drops, the need for fuel pressure to avoid vapor lock diminishes. When the ignition is turned off; a persistent connection is maintained with the ECM, fuel rail, and engine temp sensor. At some point the engine temp drops to where vapor lock is no longer an issue. When that happens, the connection stops. Pressure bleeds off naturally. | ||
| Nuts4mc |
here's an old post from 2010 that may help... http://badweatherbikers.com/buell/messages/290431/ 541006.html?1267125973 if you use the Google search at the top of this page, you will find may posts concerning this issue | ||
| Fantic97 |
I think it was my paranoia kicking in. After the issues with old fuel pump I was extra paranoid. I have accepted the fact that all is well lol. Actually now I have NO CODES so I wont bat an eye till one appears. Thanks for everyones help |
