deadbird
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Joined:
Apr 2003
Paw Paw, MI
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Ok so I am doing my fuel system diagnostics. I hooked up the FP gage so I could se it while I was driving. My base is 30 psi (I know bad from the get go) I then drove it.
W/out boost it goes to 40 by 3000 rpms and then it hesitates and doesn't go up.
With boost it stops at 50-53 psi and no higher. 15PSI boost.
When I shut it off the pressure goes up to 40psi and went back down to 38 over 10 minutes.
I am confused......
1987 5 sp.
- 4.6 2v swap.
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Tbird-fanatic
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Joined:
Oct 2011
Hazel Green, WI
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If your base is with the vacuum line connected to the regulator that's pretty close to normal, as are the rest of the readings.
1988 Tbird TC - in pieces - barn find - mods beginning while restoring
2000 F250SD XLT CCSB 7.3 Powerstoke - Daily Driver - AFE intake, Swamps tunes, straight piped
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deadbird
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Joined:
Apr 2003
Paw Paw, MI
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Yes line was connected so that's fine. But why does the pressure go up?
1987 5 sp.
- 4.6 2v swap.
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Not B Anymore
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Joined:
Apr 2001
Nokesville, VA, USA
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The pressure is going up after you shut it off because there is no longer any vacuum being applied to the regulator by the engine. "Base" fuel pressure should be ~38-40. That's the pressure you would see with the vacuum line disconnected from the regulator. When you apply vacuum to the regulator the FP goes down to the low 30's.
Brian Leavitt
'86 TC 5-Speed -- MS2x w/COP | 83 lb. injectors | T3/T4 50 Trim Stage 3 .63AR | Full 3" Exhaust - No Cat | Motorsport FMIC | Ranger Roller | Ported E6 | Walbro 255HP | Kirban | 20psi | 120-amp 3G | 8.8" 3.55 rear | '03 Cobra Wheels
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