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500 EFI fuel psi at rail/schrader valve

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500 EFI fuel psi at rail/schrader valve

Old 10-04-2022, 09:51 AM
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Default 500 EFI fuel psi at rail/schrader valve

I had a lean running cylinder on my #7 500 efi's, ended up finding the mechanical lift pump was bad and most likely caused the hot condition, I bent both valves on #7. replaced valves and head gasket and now im making sure my fuel pressure is correct, first time running it looking a the plugs they seem very white to me. Engine is running fine but my electric gauge for that motor was only reading 18-20lbs. Sent it to Livorsi and they fixed it, needle needed replaced and re-calibrated. Now that gauge is reading 33-35lbs while my other eng is reading 38-40? Hooked up mechanical gauge to schrader on rail and when key cycles pump it goes to 38 and drops to 35 after pump stops. When engine is running and vacuum lines hooked up manual gauge jumps around from 33-35 and at 3k+ rpm holds steady at around 30. At idle with vacuum line removed and plugged with my finger it reads steady 40lbs.Was going to run boat on the lake and watch psi at all rpm, should i be checking it was the vacuum line removed or no? Is 30psi on the rail with vacuum hooked up a good reading while running, i assumed after 3k rpm there wouldn't be any vacuum and my psi should be closer to 40? Thanks for any advice
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Old 10-04-2022, 11:07 AM
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40 ish is what i have on mine so check both filters
snd then your 2 electric furl pumps!
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Old 10-04-2022, 12:48 PM
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Interesting. Same thing just happened to my motor on the #7 cylinder.. currently rebuilding and will be following this thread.
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Old 10-04-2022, 12:57 PM
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OP - do a search and read on 500efi injectors. At s minimum, anytime intake is off, id get them checked. Member Arcticfriends is a good source.
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Old 10-04-2022, 01:06 PM
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Originally Posted by SB
OP - do a search and read on 500efi injectors. At s minimum, anytime intake is off, id get them checked. Member Arcticfriends is a good source.
Forgot to mention in my original post that i sent injectors in immediately and were cleaned and tested and all 100% good within spec of 40lbs
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