Lean condition after boost run, but normal after reset.

[CPR_MCOCHRAN]

I put the recal in a few mins ago. It now idles at 58 lbs of pressure. Thats with the main screw all the way back. If i screw it in any it goes up to 63. If i give it any throttle, it goes down to about 45-50 lbs. Is this normal with this kit? I'm pretty sure i put it togather correctly. Wasn't much to it.

 

[POWERHOUSE]

Matt: The signal hose for the FMU has to come from the small hoses on your throttle bodies - the vacuum lines. You should have at least two that are "teed" together, and then go to the FMU. BEFORE this signal hose actually connects to the FMU, there needs to be a check valve installed in the line, with the black side of the check valve towards the FMU. This will prevent the FMU from seeing vacuum - this is what is probably raising your fuel pressure. The check valve will only allow boost pressure to get to the FMU and influence the pressure. You can confirm this by disconnecting the hose that goes to the FMU completely - put a screw or something in it, so there won't be a vacuum leak. Let the FMU operate without a signal hose to it at all - you will see what the idle fuel pressure can be set to when you do this. In other words, if you disconnect the signal hose, and the idling fuel pressure goes down, you just found your problem. Vacuum is getting to the FMU, which should NEVER see vacuum.

Please let me know what you find . . .

 

[CPR_MCOCHRAN]

I tried pluging the barb at the rate adjust with no difference, then i tried the other barb, neither mad a difference, one acctually did increase it abit. i then decided to disassemble it again and discover the plunger was stuck and not wanting to move up or down. I got it pulled out, put a little light sand paper, then greased it good and put it back togather. Turned it back on and had 20 lbs. Adjusted screw to 40, made one change on the way the vaccum lines were run and got a constant 40 out of it. So that must have been my issue. Does anything really need to be attached to the rate adjustment barb?

 

[POWERHOUSE]

No- leave that one clear. Just run your vacuum line with the check valve in it to the other barb. Set your idling fuel pressure to 30 pounds, put your bleed adjustment screw at 1/2 turn out, and monitor the fuel pressure on the dyno . . .you should be fine!

 

[CPR_MCOCHRAN]

Thanks bro, learn something new everyday. And thanks to this site, I know where to go to learn it!

 

[CPR_MCOCHRAN]

i doubled checked the vaccum line going to the fmu and with the check, it can only see boost which is good. I have it currently have idle pressure at 35. and rise or rate 1 1/2 turns out from bottom. If it is just idling and twist the trottle, pressure goes down, wich i get, sending mor fuel, no load so no pressure. But i went down the road, built mayb 1lb and never saw a rise in pressure. subsequently it leaned out and i immediately killed the engin to the settled back down. i turned around and went back keeping RPM un 3200 made it back home. still not real sure what going on to make it not pick up pressure at boost and rise the rate. Shouldn't just twisting the trottle in the garage make it go up some?

 

[turbobusa2000]

I don't understand why you don't take it back to the person who "tuned" it for you. If you payed them you should get it redone, the bike was obviously not set up correctly. If you don't want to go back to him then take it to another tuner. If you not experienced with it then your asking for disaster by waiting.

 

[POWERHOUSE]

i doubled checked the vaccum line going to the fmu and with the check, it can only see boost which is good. I have it currently have idle pressure at 35. and rise or rate 1 1/2 turns out from bottom. If it is just idling and twist the trottle, pressure goes down, wich i get, sending mor fuel, no load so no pressure. But i went down the road, built mayb 1lb and never saw a rise in pressure. subsequently it leaned out and i immediately killed the engin to the settled back down. i turned around and went back keeping RPM un 3200 made it back home. still not real sure what going on to make it not pick up pressure at boost and rise the rate. Shouldn't just twisting the trottle in the garage make it go up some?

Matt, you can test the system fairly easily. The bike does not have to even be running. Put the tank up, and attach a small pump - like those plastic syringes used to pump air into forks- to the signal hose on the FMU. Put 12V to the fuel pump, observe the pressure, pump some air into the signal hose, and observe the pressure in the system - it should obviously go up.

I agree with turbobusa2000 - your setup is critical. If you cannot get this fuel system to respond properly, take this bike to someone who knows how to properly plumb and adjust something as simple as an FMU. Do not ride the bike on boost until you do. And again, with the larger injectors you are running, your idling fuel pressure should be 30, not 35!

 

[CPR_MCOCHRAN]

I hear both you guys loud and clear. I guess i have always done most of my own work on all my other vehicles. But those are natuarly aspirated. I don't like the feeling of not knowing everything i need to in order to work on my own bike either. I've always been mechanically minded and never scared to tear into and work anything from a washing macine, car, or computer and to have to give up and take it to someone to figure out what i did wrong drives me nuts. But i also know it is better than blowing it up and having a bigger mess to fix. I'll get it in the shop and hopefully learn that way what was wrong.