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fuel pressure dropping to nothing when going uphill

Old 03-31-2008, 02:46 PM
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Default fuel pressure dropping to nothing when going uphill

I have new plugs and wires fuel filter pcv and air filter, when going about 45-60 mph uphill my car will cut out when accelerating, the fuel pressure is about 42 at startup then to about 50 uphill then it drops to almost nothing then kicks back up and so on. The scantool showed no misfires afterwards ? any ideas ? my fuel gauge is also way out of wack . this almost always happens at high speeds uphill and sometimes on the freeway from about 50-60 or so The boost gauge reads correctly and the sc runs smooth? I was thinking fuel pump but then woulnt I notice it more frequently and not just uphill and under heavy throttle?
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Old 03-31-2008, 02:54 PM
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Crappola... re-read that and saw you are losing pressure. Disregard my other questions if you see them.
There is a quick check for the FP Regulator. by disconnecting & plugging the vacuum line. Also, should be no fuel in that line. I'm sure everybody has a lot more to offer. Sorry about my earlier mess-up
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Old 03-31-2008, 02:57 PM
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every once in a while when going 50-60 it will do it but more so uphill also except for the motor mount being bad and rubbing taking off quickly is pretty smooth and it idles pretty good
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Old 04-01-2008, 03:05 PM
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well now its doing it alot more the rpms drop off as well as the fuel pressure almost like something is restricting the fuel flow, but it checks out at startup and idle if it was the pump going bad wouldnt it do it all of the time? would the fuel pressure regulator do this?
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Old 04-01-2008, 03:36 PM
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The FP regulator would be a good guess. Have you checked it at revs (in Park)? My FP will increase when I gas it. The regulator actually bleeds off pressure and feeds via a return line to the tank.
Maybe some of the experts will jump in; but I think you can disconnect & plug the vacuum line from the regulator and the pressure should go to max. The regulator can also leak fuel into the vacuum line (bad thing) (why I suggested doing the above check earlier).
My bad. I totally missed the SC fact.
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Old 04-01-2008, 05:18 PM
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Does it lose fuel pressure at a certain RPM or boost level. The Supercharged engines have a fuel control module that may be giving you trouble.
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Old 04-01-2008, 05:36 PM
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how do I test the fuel control module? I cleaned the grounds at the inner door ares and tested all my coils today all seemed good (pretty wet under the carpet though ) and after wards when coming home I went up a slight incline and it was doing it pretty badly? rpms dropped from like 2200 to almost nothing and back again?
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Old 04-01-2008, 09:03 PM
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I can't find any diagnostic info in the factory manual. You'd have to swap it out or bypass it to see if it'* bad.
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Old 04-02-2008, 01:27 PM
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how would I go about bypassing the fuel pump module? I have the fsm also but not a whole lot in there about the fuel pump control module.
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