Like the subject says. I put on my star stage 2 kit and the fuel pressure was rising when i went into boost but all of a sudden the other day it stopped. What could be wrong. I have an FMU and walbro 255hp pump, stock injectors and i havent changed the fuel filter yet. You think it could be the fuel filter or something not right with something elst. The fuel pump is hooked up the way the factory one would be. I have heard talk of wiring it straight to the battery. Would that help? and if so how do i go about doing so. I have my fmu mounted under the hood and have a fuel inlet line coming from i believe the stock fpr, should i still have the stock fpr i have heard yes and no from diff people, and the outlet going back to the tank. What do you guys think?
Edit: I am getting a cel because my o2 sensor on the dp was shorting out my motor fuse because it was hitting the oil pan so i unplugged that sensor until i can get the 02 sensor moved to the other side. I dont think this is causing my problem but just wanted to give some more background info.

how is your vacuum line hooked up? i had the same problem with it not rising enough and it was because my vacuum line to the FMU was teed off some other lines and the boost signal was not strong enough...
check into that, try if at all possible to get the line directly plugged into the intake mani.

do you have the missing link? could also be that the vc1 that bypasses the map sensor is going bad or not connected right.

The fuel pump re-wire will help make the pump run more efficiently but you should not get fuel cut like that with it wired like the stock one.

i would check vacuum line, missing link (doubt) or probably a spring within the FPR thats broken.


Jon

1997 Eclipse RS

14.21@101mph 10/4/02

Like the others have mentioned, it's pretty important how and where you T'd off the FMU's vacuum line. If possible, you want that boost reference FMU line to come straight from the manifold, or least, there shouldn't be more than one other vacuum line that's shared with the FMU's.

thanks guys. I will do the vac line thing as i think i have the fmu, boost guage, and bov t'd on the same line. I'll try that. I doubt the spring would be broken in the fmu because it is a brand new kit with like maybe 1 mile total in boost. The map sensor bypass is hooked up correctly im pretty sure. I have it strapped down well and dont see how something could come loose on it. I'll try the fmu vac line thing and maybe thatll work.

Just as the guys said, check your lines leading into the FMU. If everythign seems ok, open up the FMU and make sure something is not misaligned.

i had the same problem also, and i had a boost leak, a big one... hah so its something with vacum, that controls boost, are you getting boost? i didnt read the whole thing

yeah im getting boost but the fuel pressure is not rising so i guess im running extremely lean if i do boost it. And if i try to get on it and am at full boost the car hesitates n whatnot. I have been driving around all week staying out of boost tho so not to damage the motor.

How do you know the pressure is not rising? FP guage? I don't think your getting fuel cut so I doubt it's the missing link. Check all the vacume things, and get some of those things their own port. I ask about the FP guage because when I installed my kit we teed it in the wrong line and it did not show rising FP but it was rising just fine.

Yeah i have a fp guage. We put the sending unit on the return line going back to the tank and my guage is only reading about 20psi there. But i figure it is working tho because when i thought my fmu was working right when i would go into boost the fp would rise to about 90. Now it goes down about 1psi when i get into boost so i and if i stay in boost up to 5psi when the wastegate opens i think it starts to studder so i let off of it and havent done that since. I will do the vac line thing tho and maybe thatll work. Oh and i thought i might have smelled fuel the other day while driving so i need to check those lines going to the tank. Would you recommend putting the fp sending unit in a different spot other than the return line where i have it. ie. in between the fmu and the fuel rail?

Yeah, the sending unit should not go between the FMU and the gas tank, as the pressure is not FUEL RAIL pressure, which is what you want to be reading. Just move it from between the fuel rail, and the FMU inlet. You will get accurate readings then.

Thats what i figured, thanks. I'll do that and do the vac line thing too.

Yeah that's the same problem I ran into when we t'd mine in the return line after the fmu. Re arange your sending unit, if possible hook it to the test port of the fuel rail, that way your getting the right readings. I fliped out about my pressure for a little while until I realized it was because of the spot we t'd into. It sounds like you may have other issues though. Let us know what you find out. BTW the test port is a -4an fitting.

Ok, now I"ve got a question. I"ve got the HRC Stage 1 kit with the Cartech. I've got a tee on the return hose: line going to return and then to gauge off the return port. I"m seeing my boost pressure go up and the EGT's are all fine and my A/F # are pretty good. Should I redo it and tee into the line that's going from the test port into the FPR? I"m confused now! AGH!

Jeremy

>Ok, now I"ve got a question. I"ve got the HRC Stage 1 kit
>with the Cartech. I've got a tee on the return hose: line
>going to return and then to gauge off the return port. I"m
>seeing my boost pressure go up and the EGT's are all fine and
>my A/F # are pretty good. Should I redo it and tee into the
>line that's going from the test port into the FPR? I"m
>confused now! AGH!
>
>Jeremy

Yes, you NEED to have the fuel pressure gauge reading the pressure at the fuel rail. It needs to be between the fuel rail test port, and the FPR inlet. Putting the gauge on the return line coming out of the FPR will yeild incorrect fuel pressure, and its NOT fuel rail pressure, which is what you want to be reading.

Ahhh, cuz according to HRC, I think it was or maybe I was just reading the directions wrong, I've got the gauge on teh return line. Oops! Looks like I got some re-hosing to do! Thanks!

Jeremy