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Discussion Starter · #1 ·
hey guys, i've figured out my wiring on the car and thats not the issue anymore...

i have a jdm aristo swap, 550cc with resistor box, a 12v fuel pump mod running a walboro 255 fuel pump and a Aeromotive FPR

the car runs PIG stupid rich at idle.. i've tried everything i can possibly google and think of. Monday i'm going to undo the 12v mod with the relay and run stock with the fuel damper. Also i'm going to install stock 440cc injectors.

for some reason when we installed the FPR ( on the return side of the rail) the FPR is reading 10psi??? and running stupid rich.. Also, while the car is running, we took off the return-line from the Aeromotive and no fuel is coming out? is this normal? i thought it was constantly flowing back to the tank?
:confused:
im completely stumped. this SHOULD NOT be an issue. Honestly i don think the stock 440cc will fix this..

PLEASE PLEASE HELP..this is the only thing keeping me from driving the car, literally.:confused::confused:
 

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Any fuel management, or did you just swap for bigger injectors, resistors and expect it to run like stock? FPR will help you fine tune the fuel pressure but your injectors are still going to create a rich mixture due to the fact that they are flowing 100+cc more that the stock ecu is expecting.
 

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What ecu are you running? If you are running the Aristo ecu with 550cc injectors, that is why you are rich at idle.
 

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I have similar setup and its not running crazy rich since I turn down the fpr to the factory setting, I do need to get a wideband though. ^_^ Here's my swap: Aristo 2jzgte, usdm cams, usdm twin, usdm tt 6spd harness, usdm obd1 ecm, denso tt fuel pump, ss braided fuel by-pass, aeromotive fpr, fpr gauge, -8AN polish fuel rail, siemens 550cc injector, and no 12volt mod. I am running without a MAF right now, besides that the car runs fine.
 

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Discussion Starter · #6 · (Edited)
I have similar setup and its not running crazy rich since I turn down the fpr to the factory setting, I do need to get a wideband though. ^_^ Here's my swap: Aristo 2jzgte, usdm cams, usdm twin, usdm tt 6spd harness, usdm obd1 ecm, denso tt fuel pump, ss braided fuel by-pass, aeromotive fpr, fpr gauge, -8AN polish fuel rail, siemens 550cc injector, and no 12volt mod. I am running without a MAF right now, besides that the car runs fine.
**stock aristo ecu***

exactly! i've seen tons and tons of people running the same setup and the car runs fine..they say usually they have to take out 10% across the board on low settings via SAFC NEO, and it runs like stock. my car is just dumping fuel almost like there is no 02 sensor...
i cant check codes since my harness had the OD thing taken out.

~~Im just confused as why when i took the Aeromotive return line off nothing came out..does it only come out after high pressure is used ie: under boost, so the excess is released back to the tank. I thought it was constantly flowing back to the tank, therefore regulating pressure.

~~i have the SAFC at -20 across on low settings. its on 6 cyl. throttle up. Pressure settting.

~would the 12v mod really effect my car that much?

THANKS SO MUCH FOR EVERYTHING HELPING!!! by far the best forum period.
 

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If you have no fuel coming back in the return line at all, something is wrong with your regulator setup. I would start there.
 

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I thought it was constantly flowing back to the tank, therefore regulating pressure.

~~i have the SAFC at -20 across on low settings. its on 6 cyl. throttle up. Pressure settting.

~would the 12v mod really effect my car that much?
There should be a ton of fuel flowing back through the return line at idle. Any fuel that isn't used is returned to the tank. Maybe your FPR is stuck? It should be a base pressure of 43psi.
 

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Discussion Starter · #9 ·
There should be a ton of fuel flowing back through the return line at idle. Any fuel that isn't used is returned to the tank. Maybe your FPR is stuck? It should be a base pressure of 43psi.
thats what i thought! i'm going to see whats up. my set up is...fuel pump => fuel rail => aeromotive FPR => tank. im going to look into tomorrow for sure! thanks for super quick replies!
 

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I have similar setup and its not running crazy rich since I turn down the fpr to the factory setting, I do need to get a wideband though. ^_^ Here's my swap: Aristo 2jzgte, usdm cams, usdm twin, usdm tt 6spd harness, usdm obd1 ecm, denso tt fuel pump, ss braided fuel by-pass, aeromotive fpr, fpr gauge, -8AN polish fuel rail, siemens 550cc injector, and no 12volt mod. I am running without a MAF right now, besides that the car runs fine.
He's running a USDM obd1 which is configured for 550cc injectors thats why it runs fine. Your stock Aristo ecu is setup for 440's and will run rich untuned. The fuel line return situation is another problem but once you figure that out you will still need to pull fuel from the factory Aristo tune.
 

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Discussion Starter · #11 ·
He's running a USDM obd1 which is configured for 550cc injectors thats why it runs fine. Your stock Aristo ecu is setup for 440's and will run rich untuned. The fuel line return situation is another problem but once you figure that out you will still need to pull fuel from the factory Aristo tune.

yes i have 20% taken out via apexi safc neo... we tried a brand new aeromotive reg (not mine) and its doing the same thing... I have no clue whats going on? could something be blocking it? do i have the regulator set up wrong?
 

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Discussion Starter · #12 ·
im actually going back to stock rail, stock 440's and stock regulator with the apexi safc. i dont care about making 500whp, i just want to drive my freaking car!! this should fix it all.
 

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Discussion Starter · #13 ·
PLEASE PLEASE PLEASE PLEASE HELP!!!! i have no clue whats going on guys!!!

fuel will NOT RETURN to the tank. been through 2 different stock rails. 2 stock FPR's and a aeromotive unit and NO FUEL is being returned to the tank AT ALL!! im soo desperate right now!
 

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PLEASE PLEASE PLEASE PLEASE HELP!!!! i have no clue whats going on guys!!!

fuel will NOT RETURN to the tank. been through 2 different stock rails. 2 stock FPR's and a aeromotive unit and NO FUEL is being returned to the tank AT ALL!! im soo desperate right now!
did you check to make sure the line is clear?
 

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If you did all that, it sounds like something is stopping the flow past the regulator.

The next step would be to check the return line. Trace the line and check for kinks or blockage. You can do a quick test by disconnecting the line at both ends and blowing some air through and see if it makes it out the other side.
 

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Discussion Starter · #16 ·
bought a fuel pressure test kit.. only 5psi was at the rail.. check PSI coming RIGHT after the pump..its only 5psi... stupid walboros.. a new denso TT pump is being installed as i type this.

i'll keep this updated.
 

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EDIT: Glad you got away from the Walbro ;)
 

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Discussion Starter · #20 ·
yep! still missfiring like crazy!

found out it was the SAFC NEO.. stook it off and the car runs PERFECT! last update hahah
 
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