| Go back to previous topic | | Forum name | Turbo/Nitrous Tech | | Topic subject | Fuel Pressure Question...is it the sfmu, or fuel pump???? | | Topic URL | https://forums.2gnt.com/dcboard.php?az=show_topic&forum=i8&topic_id=81157 |
81157, Fuel Pressure Question...is it the sfmu, or fuel pump???? Posted by lickscissors, Jan-08-05 07:27 AM
my car has been running like shit... if i try to give it a good amount of gas, it starts spitting, bucking, backfiring...just running like shit..... now i have come to the conclusion that its fuel related...i hooked up a fuel pressure gauge to the test port (95 eclipse), and when i drive it, under about 8 psi of boost, its only reading 40psi?? at idle it was close to 25..... ive checked my vacuum line to the sfmu, and its fine.... so what else could it be? i have a warbro 255 fuel pump in it, is there any way to check the sfmu??? any ideas will help...thanks doug
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81159, RE: Fuel Pressure Question...is it the sfmu, or fuel pump???? Posted by djtrickee, Jan-08-05 08:32 AM
what injectors?
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81176, RE: Fuel Pressure Question...is it the sfmu, or fuel pump???? Posted by Nitrous_RS1997, Jan-08-05 12:34 PM
and what disk/spring are you running in the SFMU? but like ^^^ said, we have to know what size injectors you are running to be able to help at all. if they are stock, your FP is INCREDIBLY low.

1997 Silver RS Built T3/T4 BB Turbo 20psi Most current 1/8th mile time: 8.1@93mph 2.015 60' 1996 Black Supra TT 2004 Silver Snake
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81202, RE: Fuel Pressure Question...is it the sfmu, or fuel pump???? Posted by lickscissors, Jan-09-05 06:52 AM
injectors are 30#, and the disk/spring?? i cant remember, but whatever it is supposed to be for 30# injectors....the car used to run good...this is a sudden thing.. doug
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81203, RE: Fuel Pressure Question...is it the sfmu, or fuel pump???? Posted by djtrickee, Jan-09-05 07:11 AM
Originally posted by lickscissors injectors are 30#, and the disk/spring?? i cant remember, but whatever it is supposed to be for 30# injectors....the car used to run good...this is a sudden thing.. doug
Take apart your SFMU and make sure the blue rubber diaphram isnt ripped or pulled away from one of the bolts. It doesnt sound like your SFMU is raising the rate like it should. DO NOT dissamble the lower part of the sfmu that is a sealed non-servicable part. Vortech has to do that part. When i got my SFMU the diaphram was ripped and needed to be replaced. The pump only supplies the fuel, the SFMU is what regulates the pressure. If you are getting flow, then I wouldnt think it would be the pump. Listen for changes in the pitch and the whine of the pump too. and Check for blockages in the feed line from the pump to the sfmu.
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81205, RE: Fuel Pressure Question...is it the sfmu, or fuel pump???? Posted by turbo8u, Jan-09-05 07:20 AM
30lb injectors? 8-10psi boost?
put in your 2.72 disc and ring, black small spring and set your idle pressure to 22-23psi and reset the ecu. 10psi boost is about 80psi max FP at WOT.
should run much better :thumbsup
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81213, RE: Fuel Pressure Question...is it the sfmu, or fuel pump???? Posted by lickscissors, Jan-09-05 11:37 AM
well those are the disk ring combination i have...mine is a little different, the springs arent colored, buti have the shorter spring, with the second to largest disk....and i have checked the diaphram, no rips...its in good condition... im so confused....cause i dont think the sfmu, could really go "bad" inside.... and i thought the same thing about the fuel pump...but maybe it cant build pressure?? any other ideas or reasons for this....thanks doug
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81332, RE: Fuel Pressure Question...is it the sfmu, or fuel pump???? Posted by lickscissors, Jan-12-05 05:02 AM
anybody?
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81333, RE: Fuel Pressure Question...is it the sfmu, or fuel pump???? Posted by siueclipse, Jan-12-05 05:06 AM
check for sharp bends in your fuel line.
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81342, RE: Fuel Pressure Question...is it the sfmu, or fuel pump???? Posted by corsagsbo, Jan-12-05 06:02 AM
by chance are your injectors Accell?... It was recently brought to my attention that there have been "some" issues with the 30 and 36's using the yellow case as opposed to the all black Siemens/Accel's. May be worth looking into.
-------------------------------------- know me as santiago boosted 420a and ej2o..(my 2liter v8 eaters)
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