Need help Im hitting 15psi but fuel prob

[daltah]

Well I tuned my 440's to aroudn 18psi for idle fuel pressure and turned the boost up to 15 psi . But at wot my fuel pressure only hits around 40psi and leans out fast so I cant step on it for that long in any gear. I use the largest ring, 2.72 disc and short gunmetal colored spring for the sfmu. I thought my fuel pressure should be around 80psi at wot. Any ideas what to do

 

[BigRand]

1st things first. update the profile, everyone is gonna want to see what else you got on their.

I'm assuming you have a walbro 255 fuel pump in there, cause if you dont' , then your pum[ will be the prob

 

[Talon ESI-T]

I read another post you had when you installed the 440cc injectors, apparently you and the SFMU dont get along.

http://www.vortechsuperchargers.com/pdf/manuals/superfmuim.pdf

Read #5 regarding the boost set screw. This is designed to limit the amount of fuel pressure you top off at. Make sure your SFMU is set up properly and adjust it properly. Most problems have been related to user error.

I also noticed you are running an inline pump to raise pressure. Make sure your pumps are both good. A quick way to test them is pinch off the return line to see if your fuel pressure raises on your gauge. IT should top off around ~120 PSI.

For future get a walbro.

Terry

 

[selmerguy]

The big disk is at what fuel ratio? Is that like 8:1? If so you might have a leak keeping your fp from going up. This happened with my fmu once and made me run lean as heck.

 

[VelocitàPaola]

The big disk is at what fuel ratio? Is that like 8:1? If so you might have a leak keeping your fp from going up. This happened with my fmu once and made me run lean as heck.

It's close to 4.2:1.

 

[Talon ESI-T]

Come on guys I posted the instructions just above.

3.62 disk = 6.5:1
2.72 disk = 4.5:1 or 4.2 depending on how you interpret the graph
2.47 disk = 3:1
2.22 disk = 2.5:1

The largest disk which you could call the big disk is actually 6.5:1 The disk he is using is the 4.5:1

In order to find out where he should be at 15psi, we need to know what his static pressure is. Static and vacuum are two different settings on the SFMU.

If his static and idle are not adjusted as a few people would liek to argue they are the same and cannot be independantly adjusted......

18 psi with disk of 4.5:1 at 15psi would yield 18psi + 67psi raised = 85psi fuel pressure

Terry

 

[selmerguy]

Come on guys I posted the instructions just above.

3.62 disk = 6.5:1
2.72 disk = 4.5:1 or 4.2 depending on how you interpret the graph
2.47 disk = 3:1
2.22 disk = 2.5:1

The largest disk which you could call the big disk is actually 6.5:1 The disk he is using is the 4.5:1

In order to find out where he should be at 15psi, we need to know what his static pressure is. Static and vacuum are two different settings on the SFMU.

If his static and idle are not adjusted as a few people would liek to argue they are the same and cannot be independantly adjusted......

18 psi with disk of 4.5:1 at 15psi would yield 18psi + 67psi raised = 85psi fuel pressure

Terry

Wow we posted at the same time. I didn't see your post with the instructions.

 

[daltah]

I adjuste the static screw to idle the fuel pressure at 18psi. The sfmu has a scre in the bleed and vacume holes but nothing it the boost hole. My inline fuel pump is working fine.Also I lost the restricto piece that is suppost to go in the vac line 2-3 inches away from the sfmu could that be causing the fuel pressure not to go up

 

[daltah]

The screw is all the way turned in on the boost port on the sfmu and as soon as the boost goes up my car leans out and I have to let off the gas. My idle fuel pressure is 18psi will raising it help? I dont understand why as soon as my boost goes up to 15psi the egts shoot right up to 1600 and I have to let off.

 

[Talon ESI-T]

Read the instruction on how the SFMU operates and how to adjust it. The stic pressure screw is not to adjust your idle pressure. Read on the operation of the vacuum screw.

Terry

 

[daltah]

The static screw on the top does control your idle fuel pressure.My fuel setup is the accel inline pump 440's injectors and a sfmu. I put the 2.72 disc and ring with the small dark spring and adjusted my idle fuel pressure to 19psi. Well I turned my mbc up to 15psi but the fuel pressure only goes up to 44psi and I heard it should be going up to 80psi. As soon as it hits 15psi of boost my egts go right up to 1600 and I have to let off. I have the boost screw turned all the way in to.
The only part Im missing on my sfmu is the little resistor peice that is suppost to go in the vac line between the sfmu and intake manifold but vortech said that wont matter.Do you know what I can do?

 

[Talon ESI-T]

If you go back and read the instructions you will find the the static pressure is with no vacuum applied and the vacuum screw is adjusted to achieve the idle pressue you want when in full vacuum which is when the engine is actually running.

Go back and read the instructions till you realize your statement that staic = Idling pressure is found to be wrong.

No one is going to help you if you dont follow the instruction vortech has set up for you.

Terry

 

[selmerguy]

If you go back and read the instructions you will find the the static pressure is with no vacuum applied and the vacuum screw is adjusted to achieve the idle pressue you want when in full vacuum which is when the engine is actually running.

Go back and read the instructions till you realize your statement that staic = Idling pressure is found to be wrong.

No one is going to help you if you dont follow the instruction vortech has set up for you.

Terry

Agreed. Silly sfmu's.

 

[XMasta19]

silly n3wbs, rules are for fools roffle waffles

 

[daltah]

If you go back and read the instructions you will find the the static pressure is with no vacuum applied and the vacuum screw is adjusted to achieve the idle pressue you want when in full vacuum which is when the engine is actually running.

Go back and read the instructions till you realize your statement that staic = Idling pressure is found to be wrong.

No one is going to help you if you dont follow the instruction vortech has set up for you.

Terry

The static screw makes my fuel pressure go up and down when the car is on and when I turn the vac screw it does nothing. I turned it in and out and it didnt change fuel pressure at idle or in boost I read the instructions and this is whats happening.
My fuel pressure under boost is 40-45psi. Ever since I put in my 440's the accel inline pump has been allot louder. I dont know if this is because of the injectors or if my stock intank pump went out. The vac screw on the sfmu does nothing when I turn it and dont know what else to do.

 

[XMasta19]

yeah umm...have you tried adjusting during atmospheric pressure, aka no vaccum no boost, with the line disconnected.

 

[Talon ESI-T]

Sounds to me like there is a problem with the SFMU then. If it doesnt operate per the instructions, then something is not right.

I posted how to check to see if your pumps are capable of pressure higher than what your seeing. My pet peeve is that i dont like to repeat myself (ok so i have a lot of pet peeves) so if you would be so kind, please go back and read my original post.

Terry