1997 Chevy Truck Low fuel Pressure Chevy K1500 CSFI system

1997 CHEVROLET TRUCK
238,000 MILES • V8 • 4WD • AUTOMATIC
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PILONA42
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Pulling my hair out. Trying to fix a low fuel pressure problem. I have replaced everything...fuel filter, fuel pump, fuel pressure regulator and she still runs at 55 lbs. (book says 60-66 for my truck). Im confused because when I cycle the key on the pump runs at 64 then when I start it she drops the 55. Does anyone have any ideas? (please dont say spider)
Feb 26, 2010 at 9:55 PM
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BLACKOP555
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is it a electronic modulated regulator or do you have a vaccum type? the spec your getting is that key on engine off? engine running spec? engine running unregulated spec?
Feb 27, 2010 at 9:19 AM
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PILONA42
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its a vacuum regulator located on the spider injection unit itself and I replaced that yesterday. it has pressure when I cycle the key on but when I start it she drops to the 55lbs
Feb 27, 2010 at 11:36 AM
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BLACKOP555
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pull off the vaccum line. does pressure go in specs then?
Feb 27, 2010 at 4:59 PM
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PILONA42
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This truck has the CSFI system and the regulator is inside the upper intake.
Feb 27, 2010 at 5:38 PM
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BLACKOP555
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ok my specs are showing 55 is good if vehicle is running. when the vaccum is put on it the pressure will drop to help with economy and prevent engine from running rich and flooding or polluting too much.
Feb 28, 2010 at 12:16 AM
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PILONA42
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Thanks for that info...so where do I go from here? I purchased a scan tool but not sure what to do with it to find the cause of my multiple cylinder misfire error code.
Feb 28, 2010 at 12:20 AM
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BLACKOP555
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with your scan tool you can look for freeze frame data and see if anything looks awry. whats the resistance on the spark plug wires?

when did this occur first? do you notice the miss? when does miss occur
Feb 28, 2010 at 7:53 AM
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PILONA42
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You can hear it missing at idle but when you put it in gear it barley wants to run...really bad!!! This all happend when I installed a new distributor. I disturbed the motor and took it in to have the cam retard set and still runs like crap. I will check the freeze frame data and get back to you with what data I find.
Feb 28, 2010 at 10:48 AM
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BLACKOP555
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so thats when it happened. why was dist replaced?

try setting the base timing yourself and see how it goes. maybe they didnt disconnect the spark advanced. could really be screwing up bad if the spark timing is off a decent amount.

make sure you remove the spark advance and the engine is warm
Feb 28, 2010 at 10:05 PM
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PILONA42
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The distributor was replaced because one of the tabs for the dist. cap screw was broken and the cap wasnt seating properly. I was always told that the ignition timing cannot be adusted. ??? Im so frustrated!
Feb 28, 2010 at 10:20 PM
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BLACKOP555
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when new dist was put in it had to be put in IDENTICAL to how the old one was. if not you will have the timing be off quite a bit just by putting the tooth one tooth off.
Mar 2, 2010 at 5:51 PM