Need help with turboed 420A fuel cut out.

[mirandaeclipse]

hi, have a problem whit my 420A turbo just when the boost goes on the intanke manifold the ecu cut´s the fuel it souds like trtrtrtrtrtrtrtrtr i already have installed a missing link and the problem still there

 

[mirandaeclipse]

my car its a 99 eclipse gs and this its my turbo setup
turbo garret t3/t4
custom manifold
walbro 255lph fuel pump
1st gen dsm bov
apexi safcII
dodge intercooler
fmu
missing link

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[vbeclipseracer]

do you have a boost gauge? if you do does the symtom happen when the gauge hits 0psi of hg? i know that the 420a has a fuel cut problem where the turbo makes the intake air neutral where the engine is neither sucking and the turbo isnt really blowing. it is like the engine is off so the computer reads no air like the engine ignition is off and cuts the fuel. i would recommend a fuel cut defender or something that prevents this.

if the whole 0psi thing isnt it disregard this post and post some more details on the problem please and ill try to help

 

[oldman]

Moved to 420a Bolt On for better and more precise responses.

 

[cs82685]

Did you buy the missing link new?
Is it clean?
Did you make sure it was working before install?
Have you made any adjustments with the SAFC II?

You've given us a good start, but the more info we've get the easier to help diagnose

 

[totaleclipse_05]

I would dump the Missing Link and get an FCD from Paul on here. I use his and never have a problem with fuel cut anymore.

 

[dsmclipse97]

I would dump the Missing Link and get an FCD from Paul on here. I use his and never have a problem with fuel cut anymore.

I second that, missing links have been known to crap out. An electronic fuel cut defender works much better and im sure paul will hook you up.

 

[mirandaeclipse]

cs82685 Did you buy the missing link new?
Is it clean?
Did you make sure it was working before install?
Have you made any adjustments with the SAFC II?

yep, i just bougth the missing link brand new its a synpase and i notice that it looks a little dirty on the side were the map goes on. but i did not pay attention the fuel cut comes on when the boost goes to 2 psi in the boost gauge, and whit the safc i have this:

LOW TH 10% HI TH 50%

LOW -33%, -31%, -29%, -28%, -28%, -26%, -26%, -24%, -22%
HI -33%, -31%, -24%, -12%, -8%, -8%, -6%, -6%, -4%

the sensor pressure its 06 in 06 out

i forgot to tell you that before i install the missing link i disconect the fmu and let alone the fuel management to the safc that was a friend of mine told me to do ( he have a 93 nissan sentra se-r turbo) he told me that the safc could work better whit out the fmu, i will reconect the fmu and try to clean the missing link, i hope that it works but if not i will contact to veolcitapaola and see if he cand send me a fcd to los mochis sinaloa mexico there´s were i live.

 

[dsmclipse97]

SAFC does not work with our cars... If your getting any boost then the missing link is not the problem. Try reinstalling the FMU and disconnect the SAFC-II and let us know.

 

[DSMcrazy3]

If your FMU isn't connected that's your problem. Missing links are known to malfunction, and I recommend switching to a FCD.(talk to Paul) However like I said if the FMU isn't connected that's your problem. Your friend who told you not to connect it must not know much about 420a, but there's no way the walbro alone can provide the amount of fuel pressure needed to support that airflow.

 

[link16]

Missing link is a hit or miss, I have heard nothing but good things about Paul's FCD. Put your FMU back in, like DSMcrazy3 said.

 

[mirandaeclipse]

i put again the fmu, and cleaned the missing link and nothing good happend´s but there´s something rare, in first and second gear the fuel cut comes when the boost gauge marks 2 psi but in third gear the fuel cut comes at 3.5 psi i dont know what to do

 

[DSMcrazy3]

You're sure the FMU is hooked up correctly?

 

[mirandaeclipse]

i think so, the fmu its placed just before the fuel rail, and the vacum line came from the intanke manifold.

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[VelocitàPaola]

Hmm... the FMU comes just after the fuel rail...

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[DSMcrazy3]

Before or after, the way he describes it's setup, is the correct way.

 

[dsmclipse97]

Hmm... the FMU comes just after the fuel rail...

Im sorry, im working on my FMU as well and im a little confused... can the FMU be placed in the engine bay, right after the fuel rail? or does it need to go next to the fuel tank? ive seen both so im a little confused.

 

[VelocitàPaola]

Depends on your fuel system. The early model 2G N/Ts had a return line coming straight from the fuel rail; these models are capable of having the FMU mounted in the engine bay.

Later models had a "returnless" system, in which the FMU must be mounted by the tank (configuration #1); unless you run your own return line from the rail (configuration #2).

 

[dsmclipse97]

I have the same FMU that mirandaeclipse used in his picture which uses SS line fittings while the stock line fittings are rubber. So how would i hook up my FMU? should i change out the FMU fittings to accept rubber lines or try to run SS lines, in which i have no idea how i would hook those into the rest of the fuel system. Sorry for hijacking but i cant seem to wrap my head around this damn FMU...

 

[VelocitàPaola]

Just replace the fittings with brass barbs for the rubber lines. You can always switch/upgrade later.

 

[cs82685]

i think so, the fmu its placed just before the fuel rail, and the vacum line came from the intanke manifold.

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So you're saying you have the fmu before the fuel rail, ie on the driver side, and the line that goes between the fuel rail and the fmu, goes into the driver side of the fuel rail? If so, then that's setup wrong and you need to look at the diagrams Paul posted. To determine if you have the early or late fuel system (even though you should have the late model system based on your year) take a look at the passenger side rail and see if there is a return line (there shouldn't be if it's late) if not then you need to get the FMU to the back of your car.

Description for late model fuel system to go along with Paul's diagram...

Take out the bottom portion of your back seat, remove the metal cover under the passenger side seat and you will see two lines going into the tank. One's metal, one's rubber. The FMU goes in line with the rubber one. That means the end of the rubber line going into the tank gets taken off and put into the side port of the fmu. Then you get another rubber line and attach it to the bottom port of the fmu and the top of the tank where you originally remove the other rubber line. Of course, you will need to find somewhere to mount the fmu underneath the car before doing this so you know how long the rubber lines need to be.

 

[dsmclipse97]

Take out the bottom portion of your back seat, remove the metal cover under the passenger side seat and you will see two lines going into the tank. One's metal, one's rubber. The FMU goes in line with the rubber one. That means the end of the rubber line going into the tank gets taken off and put into the side port of the fmu. Then you get another rubber line and attach it to the bottom port of the fmu and the top of the tank where you originally remove the other rubber line. Of course, you will need to find somewhere to mount the fmu underneath the car before doing this so you know how long the rubber lines need to be.

Dont forget, you will need to run a vacuum line to the back of the car from the intake manifold. I got about 10 feet which should be more than enough.

 

[mirandaeclipse]

i did it this way

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and that could be the reason for my problems, my car its a 99 gs

 

[VelocitàPaola]

That's precisely your problem. An FPR (i.e. FMU) works by restricting flow in the return line, thereby creating higher pressures in the feed line and fuel rail.

By putting the FMU before the fuel rail, you're only restricting fuel flow, rather than increasing it. Configure your setup like either of the diagrams I posted to fix the problem.

 

[mirandaeclipse]

VelocitàPaola That's precisely your problem. An FPR (i.e. FMU) works by restricting flow in the return line, thereby creating higher pressures in the feed line and fuel rail.

By putting the FMU before the fuel rail, you're only restricting fuel flow, rather than increasing it. Configure your setup like either of the diagrams I posted to fix the problem.

thanks, i will follow the configuration number one, and see what happends