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How do you check fuel pressure?

  • Thread starter Thread starter stangman16
  • Start date Start date Jul 4, 2007

stangman16

Active Member
Nov 16, 2004
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San Antonio, TX
Jul 4, 2007
#1
  • Jul 4, 2007
  • #1
...without a schrader valve on your fuel rails? I guess I had bought the wrong rails.

After changing the coil and battery I am getting a good blue spark now, but my EFI project still won't start. When I spray starting fluid into the TB the car fires for about 1 second or less and just quits. I have checked with a noid light and the injectors are firing, and also I cleaned the IAB valve and ensured the timing was set at 10°. I can hear my fuel pump prime for about 2-3 seconds, but I don't know if this pump is actually good enough for producing the right amount of PSI needed. The person I bought it from stated their friend had it on a fox-body EFI stang. If I don't have enough PSI, that will not allow it to start - right?

Happy 4th!!
 

cenok is family

15 Year Member
Jun 25, 2003
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Norman, Ok
Jul 4, 2007
#2
  • Jul 4, 2007
  • #2
yes, no fuel = no start. if you don't have a shrader valve to tap into the fuel line anywhere, you'll probably need to get an electric fuel pressure gauge. are you using factory fox fuel lines? is so, there's a shrader valve on one of them, kinda under and behind the alternator.

*edit* yeah i just realized this is on a 66 so i'm going to assume you're not using fox fuel lines. lol. you'll probably just have to get an electric fuel pressure gauge.

happy 4th of july back at ya!
 

stangman16

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Nov 16, 2004
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Jul 4, 2007
#3
  • Jul 4, 2007
  • #3
Thanks for the reply,

I was under the impression when I bought the fuel lines that they were from a 89-93 fox mustang, but I've checked all over and I cannot find the schrader valve... so I guess I got ripped off. heh.

Looks like the fuel pump I am using is a Holley 97 GPH “RED” Electric Fuel Pump and it on Holley's site it shows the maximum pressure is 7 PSI..... I just want to be sure before I go buy a new pump that this could be it that is preventing the car to start.
 

jrichker

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#4
  • Jul 4, 2007
  • #4
The stock EFI pump puts out 60 PSI or more. The shunt type fuel pressure regulator drops that to 38-40 PSI by returning fuel to the tank. Many adjustable regulators have a gauge port on them.
 

stangman16

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Nov 16, 2004
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San Antonio, TX
Jul 6, 2007
#5
  • Jul 6, 2007
  • #5
Okay, I just bought a Holley inline fuel pump P/N 12-920. I just want to be sure I do not damage this thing, as it states a low-pressure fuel filter must be used on the inlet of the fuel pump, and a High pressure filter on the outlet of the pump to protect the fuel inj system. Well, I have a stock '91 mustang fuel filter - is that a low pressure filter? If so, could I pick up a high pressure filter at advance or is that a special order part?
 

jrichker

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#6
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Stock EFI setup filter is after the pump, so it is a high pressure filter.
 

Booksix

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Dec 8, 2003
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Jul 6, 2007
#7
  • Jul 6, 2007
  • #7
Just an added note for you. Earlier fox mustangs had the shader valve on the metal lines that went from the chassis lines to the fuel rails (as stated, putting it somewhere behind the alternator) whereas 89+ (i believe) moved it to the fuel rails. So you probably do have the fox stang rails, but the earlier setup... and by making your own fuel lines that go straight up to the fuel rails you skipped over the schrader valve...
 

stangman16

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Nov 16, 2004
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#8
  • Jul 6, 2007
  • #8
Good deal. I just need to find a low pressure filter now. Would a low pressure filter be one for a carb'd engine?
 

jrichker

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#9
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stangman16 said:
Good deal. I just need to find a low pressure filter now. Would a low pressure filter be one for a carb'd engine?
Click to expand...

That would work well.
 
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