Jusblowit
Certified Looney
I'm on the very last leg of this project that has taken several years to get to this point...
http://www.xs650.com/threads/f-i-2-forced-induction×fuel-injection.56603/page-2#post-681076
It's (among other things) an EFI conversion run on Microsquirt.
Actually I shouldn't say I'm on the last leg because each one of the past four weekends was going to be the one when I fired it up for the first time...and then some unforeseen problem surfaces.. Yesterday was no exception.
I'm using this regulator:
https://www.jegs.com/i/Holley/510/1...hTXQqefEWjSYl4Tt1WoMmZjm0Sks6Y5AEOvcNSF3FcoD#
The fuel system flow chart, as recommended by Holley, is as follows:
Tank>pre filter>gravity feed into inline fuel pump>post filter>fuel rail>return line>bypass fuel pressure regulator(w/take-off for pressure gauge)>fuel tank return port.
Wiring, as recommended by the suppliers of microsquirt is such that the fuel pump relay is controlled by the ECU. It turns on for 2 seconds when the ignition is turned on which is meant to pressurize the system. It will then turn off and come on again only when the ECU reads a tach signal i.e. during cranking and running. This relay also powers the injectors and coils. This is a safety feature.
I put gas in the tank for the first time and pressurized the fuel system by running the fuel pump in test mode to check for any leaks. The tank, fittings, and all the lines are good, no leaks, but two problems popped up:
1. Tank venting:
Fuel seeps out past the seal of the filler cap when the system is pressurized. At first I thought my return port was squirting the returned fuel at the underside of the cap. But the more I think about it the more I am convinced that I'm building positive pressure in the tank, forcing out vapour. This seems to be confirmed as when I put the bike away , bringing it in from the chilly air to heated inside, I noticed the same thing happening even though the system hadn't been pressurized in at least 20 minutes.
The filler cap has a rubber diaphragm one-way check valve that allows air to enter but nothing to escape. This probably works for carbed bikes which with no return line, only draw fuel OUT of the tank and need to let in air to avoid a vacuum, but with the pressure created by the high pressure pump I seem to be building pressure in the tank that has no escape route. I need a vent that will allow positive pressure to escape - online research confirms that factory EFI bikes have a provision for this.. This raises a safety concern. without a check valve, what is stopping fuel from leaking if the bike finds itself on it's side? With many old bikes, the answer is nothing. Actually a friends' 2011 ("new" by comparison) Ducati Monster recently got knocked over while parked by some anonymous do-gooder... when it was found in the morning gas had spilled all over the tank peeling the paint off one of the plastics. So maybe the answer is bikes just have an open vent? Many dirt bikes do... but dirt and plastic don't spark like metal and asphalt if you go down... there is such a thing as a rollover ball valve that cars utilize... they're kind of large tho and I think they would only work if you landed completely upside down as opposed to on your side, as a bike would. Just ordered one of these:
https://fortnine.ca/en/moose-vent-cap
But I'm not sure that it's not just a one way check valve (air in, nothing out) which I already have.
If the answer is just "open vent" then all I have to do is remove the diaphragm form my filler cap vent, but I'm wondering if there's a safer way?
2. Fuel pressure
For one, the fuel pump priming pulse that the ECU fires isn't long enough to get the system up to the required pressure (43psi). Not a problem, the length of that is programmable. The trickier thing is the regulator doesn't hold pressure with the pump not running. I knew that aftermarket regulators did not, as opposed to the OEMs, but I thought it would be on the order of minutes. It's not- at least not with this regulator, as soon as the pump turns off, the pressure drops back to zero within seconds. The practical implication is that if I don't hit the starter immediately at the end of the prime pulse I will have to crank for 3-4-5 seconds untill pressure builds again. That can't be good for the battery....and forget about kick starting. Not sure if other aftemarket regulators are any different.... read on the Aeromotive (about as expensive a regulator as you can buy) website something about how this is a feature not a bug, and that the OEMs retaining pressure for 30 minuted is an EPA requirement and actually compromises performance, although they don't say how.
One idea is to wire in a momentary switch that holds the fuel pump on prior to hitting the starter... perhaps I could use the clutch safety switch that currently is not in use... ? Those who have done it, what did you do?
http://www.xs650.com/threads/f-i-2-forced-induction×fuel-injection.56603/page-2#post-681076
It's (among other things) an EFI conversion run on Microsquirt.
Actually I shouldn't say I'm on the last leg because each one of the past four weekends was going to be the one when I fired it up for the first time...and then some unforeseen problem surfaces.. Yesterday was no exception.
I'm using this regulator:
https://www.jegs.com/i/Holley/510/1...hTXQqefEWjSYl4Tt1WoMmZjm0Sks6Y5AEOvcNSF3FcoD#
The fuel system flow chart, as recommended by Holley, is as follows:
Tank>pre filter>gravity feed into inline fuel pump>post filter>fuel rail>return line>bypass fuel pressure regulator(w/take-off for pressure gauge)>fuel tank return port.
Wiring, as recommended by the suppliers of microsquirt is such that the fuel pump relay is controlled by the ECU. It turns on for 2 seconds when the ignition is turned on which is meant to pressurize the system. It will then turn off and come on again only when the ECU reads a tach signal i.e. during cranking and running. This relay also powers the injectors and coils. This is a safety feature.
I put gas in the tank for the first time and pressurized the fuel system by running the fuel pump in test mode to check for any leaks. The tank, fittings, and all the lines are good, no leaks, but two problems popped up:
1. Tank venting:
Fuel seeps out past the seal of the filler cap when the system is pressurized. At first I thought my return port was squirting the returned fuel at the underside of the cap. But the more I think about it the more I am convinced that I'm building positive pressure in the tank, forcing out vapour. This seems to be confirmed as when I put the bike away , bringing it in from the chilly air to heated inside, I noticed the same thing happening even though the system hadn't been pressurized in at least 20 minutes.
The filler cap has a rubber diaphragm one-way check valve that allows air to enter but nothing to escape. This probably works for carbed bikes which with no return line, only draw fuel OUT of the tank and need to let in air to avoid a vacuum, but with the pressure created by the high pressure pump I seem to be building pressure in the tank that has no escape route. I need a vent that will allow positive pressure to escape - online research confirms that factory EFI bikes have a provision for this.. This raises a safety concern. without a check valve, what is stopping fuel from leaking if the bike finds itself on it's side? With many old bikes, the answer is nothing. Actually a friends' 2011 ("new" by comparison) Ducati Monster recently got knocked over while parked by some anonymous do-gooder... when it was found in the morning gas had spilled all over the tank peeling the paint off one of the plastics. So maybe the answer is bikes just have an open vent? Many dirt bikes do... but dirt and plastic don't spark like metal and asphalt if you go down... there is such a thing as a rollover ball valve that cars utilize... they're kind of large tho and I think they would only work if you landed completely upside down as opposed to on your side, as a bike would. Just ordered one of these:
https://fortnine.ca/en/moose-vent-cap
But I'm not sure that it's not just a one way check valve (air in, nothing out) which I already have.
If the answer is just "open vent" then all I have to do is remove the diaphragm form my filler cap vent, but I'm wondering if there's a safer way?
2. Fuel pressure
For one, the fuel pump priming pulse that the ECU fires isn't long enough to get the system up to the required pressure (43psi). Not a problem, the length of that is programmable. The trickier thing is the regulator doesn't hold pressure with the pump not running. I knew that aftermarket regulators did not, as opposed to the OEMs, but I thought it would be on the order of minutes. It's not- at least not with this regulator, as soon as the pump turns off, the pressure drops back to zero within seconds. The practical implication is that if I don't hit the starter immediately at the end of the prime pulse I will have to crank for 3-4-5 seconds untill pressure builds again. That can't be good for the battery....and forget about kick starting. Not sure if other aftemarket regulators are any different.... read on the Aeromotive (about as expensive a regulator as you can buy) website something about how this is a feature not a bug, and that the OEMs retaining pressure for 30 minuted is an EPA requirement and actually compromises performance, although they don't say how.
One idea is to wire in a momentary switch that holds the fuel pump on prior to hitting the starter... perhaps I could use the clutch safety switch that currently is not in use... ? Those who have done it, what did you do?
. 
