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98 ss fuel pressure low on new twin 255's Help fast please!!

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Old 10-28-2011, 07:06 PM
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Default 98 ss fuel pressure low on new twin 255's Help fast please!!

My roomates car is a 98 ss, forged 346 60# injectors, turbo etc etc. He was having fuel pressure issues, car would idle at about 43 psi and then getting into rpm's would drop off. Well we put a new regulator in the tank, and did new twin walbro 255's one on a 4 psi hobbs switch. Car bumped up to only 47 psi with the new pump. Then when getting in boost it would drop off and bump up just a little bit when the 2nd pump kicked in. The car sat for a week at the paint shop. Picked it up today and the car idles at 38-40 psi and drops off even before getting into boost. The car has a racetronix hotwire kit on the main pump and we followed MightyMouse's thread on the twin pumps so everything should be working fine. Anyone have any ideas on whats going on?
Old 10-30-2011, 04:28 AM
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Can't help you, but MightyMouse's thread doesn't have any pictures anymore, where did you get them?
Old 10-30-2011, 05:22 AM
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dumb question Brandon, but did you guys swap the fuel filter?
Old 10-30-2011, 08:29 AM
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Leaking in the tank...........[Unless the filter is nearly plugged shut, that is]
Old 10-30-2011, 05:49 PM
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has a brand new AC delco filter, we thought that might have been it but we got maybe 1-2 psi out of that., but still really low on the PSI. We pulled the pumps back out and checked everything, there is no leaks coming from the lines. still sitting around 45 psi. I think the next step is putting an -8 feedline from the tank and putting an aftermarket regulator at the stock feel line (making it a new return line).
Old 11-01-2011, 03:24 PM
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I thought that 98s had the regulator mounted in the front of the car?
Old 11-04-2011, 08:27 AM
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ill try to fix the pics.

far as dropping fuel pressure, you will see it drop a little with the factory regulator, how much we talking about?

for all the other money in the car you may want to send it a boost reference, or mount another reg. externally.
Old 11-07-2011, 09:16 AM
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Originally Posted by MIGHTYMOUSE
ill try to fix the pics.
That would be cool!
Old 11-07-2011, 04:29 PM
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the pics are here until i can get the thread updated

http://www.streetfire.net/photo/dsc00184jpg_2039323.htm
Old 11-07-2011, 06:04 PM
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Thanx! Installed my own twin this night, will probably post some pics for critics and opinions




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