An issue with the rcc stage 1 FMU...


#1
I have experienced fuel pressure spikes running my rcc stage 1 set at 6 psi, with fuel pressure going above 110 psi. The first time this happened I shipped the fmu back to BEGI and they rebuilt and updated the insides. Now it did it again and I am wondering what to do????? Pressure relief valve is fine, and return line is not kinked. Any advice appreciated!
 

POWERHOUSE

Frank
Site Sponsor
Registered
#2
I have experienced fuel pressure spikes running my rcc stage 1 set at 6 psi, with fuel pressure going above 110 psi. The first time this happened I shipped the fmu back to BEGI and they rebuilt and updated the insides. Now it did it again and I am wondering what to do????? Pressure relief valve is fine, and return line is not kinked. Any advice appreciated!
How are you connecting the FMU? Is your signal hose going to the single barb coming off a vacuum line, or are you running that signal hose off the plenum itself? What is you baseline idling fuel pressure set at? How many turns out is the bleed screw, and do you have anything connected to the barb next to the bleed screw? What type of gauge are you using to monitor the fuel pressure? Are you convinced your gauge is accurate? Does it have a steady needle, or does it tend to flutter?
 
#4
How are you connecting the FMU? Is your signal hose going to the single barb coming off a vacuum line, or are you running that signal hose off the plenum itself? What is you baseline idling fuel pressure set at? How many turns out is the bleed screw, and do you have anything connected to the barb next to the bleed screw? What type of gauge are you using to monitor the fuel pressure? Are you convinced your gauge is accurate? Does it have a steady needle, or does it tend to flutter?
I think the signal hose is connected to a vacuum line, I will check when im at the bike. Idle fuel pressure is set at 42psi, bleed screw 1/2 turn out, no ck valve on the bleed screw. I am using a mechanical fuel pressure gauge, and have double checked it with another gauge just to make sure, so im positive its not a false reading. The needle on fuel pressure gauge does have a slight vibration to it, vibrating between 40-43 psi at idle, at full boost between 88-91ish (before this problem started.)
 

POWERHOUSE

Frank
Site Sponsor
Registered
#6
I think the signal hose is connected to a vacuum line, I will check when im at the bike. Idle fuel pressure is set at 42psi, bleed screw 1/2 turn out, no ck valve on the bleed screw. I am using a mechanical fuel pressure gauge, and have double checked it with another gauge just to make sure, so im positive its not a false reading. The needle on fuel pressure gauge does have a slight vibration to it, vibrating between 40-43 psi at idle, at full boost between 88-91ish (before this problem started.)
If the signal hose is connected to vacuum, make sure there is a one-way check valve in that line preventing the FMU from seeing vacuum . . . you should be able to blow through that line towards the FMU, but not back the other way.
 
#7
is than an electric gauge sender i'm looking at in the pic, test it and the gauge , had all sorts of faults from an electric sender on oil pressure, vibration kills them fast
 
#8
is than an electric gauge sender i'm looking at in the pic, test it and the gauge , had all sorts of faults from an electric sender on oil pressure, vibration kills them fast
That is an older picture. Its a glowshift electronic pressure gauge, but currently have a mechanical gauge on there now.
 
#9
Mike from Quick Cycles, who built this bike, took a look at it. Mike turned the bleed off screw out all the way and it was still building to much pressure. He took it apart, found nothing wrong, reassembled it and it worked fine, for a short while. After a few passes on the dyno and it was back up to making above 100 psi again! I am super frustrated with this thing. Im sending it back to Begi again and see what they have to say about it.

If anyone has a piggyback set up they want to sell I might be interested ???
 
#12
Just learned of the stand alone ecu option. Looks cheaper than piggyback. :happy:

not sure i would want to use a standalone that cost less than the piggyback , which one ??

beauty of something like a secondary controller or piggyback is the std ecu runs all the standard stuff just fine and the add on just dooes what it needs on top of that

once you get into a standalone your often looking for another gauge set , crank or cam triggers , then the config files , its usually easy but expensive or cheap and never ending
 
#13
not sure i would want to use a standalone that cost less than the piggyback , which one ??

beauty of something like a secondary controller or piggyback is the std ecu runs all the standard stuff just fine and the add on just dooes what it needs on top of that

once you get into a standalone your often looking for another gauge set , crank or cam triggers , then the config files , its usually easy but expensive or cheap and never ending
The Interface pnp ( Hayabusa PnP - Megasquirt based custom motorcycle ECU's and acc. ) will let you run oversize injectors, and still make it driveable in the low end. It sounds like it plugs right in and takes the place of the stock ecu! but I need to make sure before I get all excited lol. :laugh: It costs 1,000 dollars, plus a few hundred for injectors, plus a few hundred for tuning and setting up makes it still cheaper than going to piggyback setup.
 

Most likes - Past 7 days

Forum statistics

Threads
170,595
Messages
3,066,093
Members
46,788
Latest member
nightismine
Top