Question on loosing fuel pressure going down track. - Page 3

Jeff Stout · 01-22-2020, 10:39 AM

Quote:

Originally Posted by Hacksaw

If you are using a fuel filter, check the Microns.

It is a Summit -8 inline 40 micron filter

Ed Wright · 01-22-2020, 11:37 AM

Quote:

Originally Posted by Jeff Stout

1.88 60ft 14.50 ET.

Won’t be G forces.

jmantle · 01-22-2020, 04:34 PM

Have you checked the pressure before the regulator? Most pumps put out about 15 PSI.
You may have a low pressure pump not designed to use with a regulator or the pump is no good.

Jim Mantle V/SA 6632

Dave Noll · 01-22-2020, 07:02 PM

Quote:

Originally Posted by Jeff Stout

Side note is the o2 is going from 13.5 to 11 in high gear.

Trust the sensor, there isn't a problem. Its 11:1 in high gear. My cars AFR gets leaner as RPM increases an gets richer at each shift. (completely different carb)

MRE 7171 · 01-22-2020, 07:20 PM

Jeff did you get a chance to check the volume in a fuel jug for 60 seconds at the front of the car and what volume did you get?

Jeff Stout · 01-22-2020, 07:45 PM

Quote:

Originally Posted by MRE 7171

Jeff did you get a chance to check the volume in a fuel jug for 60 seconds at the front of the car and what volume did you get?

I just did now im right at a gallon in 60 seconds. That was tested using line right at carburetor

gsa612 · 01-22-2020, 08:12 PM

Quote:

Originally Posted by Jeff Stout

I just did now im right at a gallon in 60 seconds. That was tested using line right at carburetor

On a free flow test it should be a gal.in 30 seconds especially with a Q-jet...gsa612

Danny Ashley · 01-22-2020, 08:14 PM

Should pump a gallon in 30 seconds. I think you just found your problem.

ss3011 · 01-22-2020, 08:25 PM

Its weird that the O2 sensor goes rich , sounds like some work needs to be done to straighten out the fueling of the carb . That being said the carb is using more fuel than can be supplied to it , so the pressure drops . My recommendation is to figure out what's up with the carburetor , but also make sure your fuel system is up to the task . My Q-jet is fed from a BG400 pump through a dash 10 line , and stays right at 6.5 psi throughout the run . Dyno pulls show the A/F ratio varies from 12.8 at 5000rpm to 12.4 at 7400 rpm .

Mark Yacavone · 01-22-2020, 09:25 PM

Quote:

Originally Posted by Danny Ashley

Should pump a gallon in 30 seconds. I think you just found your problem.

Agree..I've had cars under 25 sec.

BTW, I was just giving Jeff a hard time. Sorry some of you missed this whole sordid tale, for 5 years ...Check out the build section once in a while ;-)

01-22-2020, 04:34 PM	#23
jmantle Member Join Date: Feb 2008 Location: Black Creek, BC Canada Posts: 331 Likes: 77 Liked 172 Times in 81 Posts	Re: Question on loosing fuel pressure going down track. Have you checked the pressure before the regulator? Most pumps put out about 15 PSI. You may have a low pressure pump not designed to use with a regulator or the pump is no good. Jim Mantle V/SA 6632

01-22-2020, 07:20 PM	#25
MRE 7171 Junior Member Join Date: Sep 2018 Posts: 58 Likes: 41 Liked 95 Times in 24 Posts	Re: Question on loosing fuel pressure going down track. Jeff did you get a chance to check the volume in a fuel jug for 60 seconds at the front of the car and what volume did you get?

01-22-2020, 08:14 PM	#28
Danny Ashley Member Join Date: Nov 2001 Location: Marion,In. Posts: 267 Likes: 60 Liked 110 Times in 29 Posts	Re: Question on loosing fuel pressure going down track. Should pump a gallon in 30 seconds. I think you just found your problem.

01-22-2020, 08:25 PM	#29
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 909 Likes: 70 Liked 239 Times in 114 Posts	Re: Question on loosing fuel pressure going down track. Its weird that the O2 sensor goes rich , sounds like some work needs to be done to straighten out the fueling of the carb . That being said the carb is using more fuel than can be supplied to it , so the pressure drops . My recommendation is to figure out what's up with the carburetor , but also make sure your fuel system is up to the task . My Q-jet is fed from a BG400 pump through a dash 10 line , and stays right at 6.5 psi throughout the run . Dyno pulls show the A/F ratio varies from 12.8 at 5000rpm to 12.4 at 7400 rpm .