fuel pressure guestion

3

331 stang91

Member

Oct 16, 2004

261

0

16

wisconsin

Jul 4, 2005

#1

• Jul 4, 2005

• #1

So I run me fuel pressure at about 39 . When I'm under the hood and pull on the throttle allitle the pressure drops to about 34 or so . Is it normal for it to drop so much? Thanks

 

DMAN302

My mom says thanks for the pearl necklace.

Nov 8, 2003

2,120

2

59

windsor, Canada

Jul 4, 2005

#2

• Jul 4, 2005

• #2

Pressure may go up..if vac line attached and given throttle, however pressure should NOT drop when throttle is applied. You need to look into the cause.

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

31,179

33

129

Jul 4, 2005

#3

• Jul 4, 2005

• #3

Does the pressure snap right back up after a second? Initially there can be a lag (pressure dips then swings back up).

Good luck.

 

3

331 stang91

Member

Oct 16, 2004

261

0

16

wisconsin

Jul 4, 2005

#4

• Jul 4, 2005

• #4

I'll check today, any suggestions as to why this may be happening? New 190 pump and 24 lb injectors?

 

DMAN302

My mom says thanks for the pearl necklace.

Nov 8, 2003

2,120

2

59

windsor, Canada

Jul 4, 2005

#5

• Jul 4, 2005

• #5

Try fuel filter..could be clogged.

 

3

331 stang91

Member

Oct 16, 2004

261

0

16

wisconsin

Jul 4, 2005

#6

• Jul 4, 2005

• #6

Filter is also new

At idle 39

- vac line 42 1/2

with throttle consistant throught all rpm's 32 1/2

I did upgrade my feed line to 3/8 and left the return line stock, but don't think that would be the problem?

Any suggestions?Thanks for the responses so far.

 

3

331 stang91

Member

Oct 16, 2004

261

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16

wisconsin

Jul 4, 2005

#7

• Jul 4, 2005

• #7

Anyone?

 

Michael Yount

Mustang Master

Apr 10, 2002

9,039

6

79

Charlotte, NC

Jul 4, 2005

#8

• Jul 4, 2005

• #8

Your pressure should be measured at warm idle with the vacuum line off the regulator and plugged; it should be 38-39psig under those conditions. WHen you plug the vacuum line back onto the reg at warm idle it should drop down into the 31-35 psig range (higher end if you have more cam less/vaccum; lower end if you have a milder cam/more vacuum).

 

3

331 stang91

Member

Oct 16, 2004

261

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wisconsin

Jul 4, 2005

#9

• Jul 4, 2005

• #9

thanks I always set the pressure with the line on!

 

3

331 stang91

Member

Oct 16, 2004

261

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wisconsin

Jul 4, 2005

#10

• Jul 4, 2005

• #10

but does anyone know why it drops when I give the car throttle? You saying cap of the top of the regulator?thanks

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

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Jul 4, 2005

#11

• Jul 4, 2005

• #11

331 stang91 said:

You saying cap of the top of the regulator?thanks

Click to expand...

Nope, he is saying to cap off the vac line which attaches to the top of the regulator.

 

Michael Yount

Mustang Master

Apr 10, 2002

9,039

6

79

Charlotte, NC

Jul 4, 2005

#12

• Jul 4, 2005

• #12

If you're running 39 with vacuum line on you're running too much pressure. Your technique for setting the pressure is incorrect.

 

3

331 stang91

Member

Oct 16, 2004

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wisconsin

Jul 4, 2005

#13

• Jul 4, 2005

• #13

I see thanks!