Fuel pressure running off at the worst time

bert powell · 02-24-2012, 10:05 AM

Guys, been aggravated with this problem on and off for a while. I have a GT/CA Camaro with a Qjet, Magnafuel 500 pump and the large 2 port reg. I added a fuel guage at the pump and was getting 26 psi at 12v. When I switch to 16v it would peg the guage over 30psi. So I tried to reduce the pressure and when it did come down the pump bypass would leak because it was screwed out too much. I cut two coils off the bypass spring and got the pressure at 26 psi at 16v. Reset the front regulator at 6 psi and went to test. First run fine. Second run, after the burnout the front pressure went to 12+psi. Got back to pit and cycled the pump, sat there at 6psi and would not move. Going to check the regulator for trash again but did not find any before.

Anyone used the Magnafuel large 2 port regulator before without issues? Thinking about changing it.

How much can I lower the pump pressure and still be safe, thinking about dropping it to 18psi.

I had a carb fire trying to get the thing down the track before and would like to fix this permanently. Any ideas?

Bob Gullett · 02-24-2012, 10:31 AM

After installing my Magnafuel system I was having a problem with the large port regulator as well. Out of the blue the pressure would spike pegging my guage and of course blowing the needle and seat off the q-jet. I contacted magnafuel and they suggested along with the rear fuel filter to add an inline filter just before the regulator. Since I have done that never an issue again. They claim that the regulators are very sensative and the smallest particle of anything can cause the regulator not to work properly.

philbilly · 02-24-2012, 10:35 AM

Bert I would check the reg. out not to mention I would check the bypass valve on the pump for some foreign object. If it held steady like your post then just out of the blue jumped up like that it is probably in your reg.

Bob Gullett · 02-24-2012, 10:40 AM

To add to my post I did have a friend who had the same problem and magnafuel replaced the regulator no charge.

Bill Grubbs · 02-24-2012, 12:33 PM

Yes!!! the regulator is very sensitive to contamination. We fought this problem for most of the year last year, new fuel lines, filters, pump wiring, cleaned and serviced pump and regulator. We finally fixed it by adding a MagnaFuel filter just prior to the regulator (huge cudos to Robbie Ward @ MagnaFuel). We now have over 40 passes on the car with no problem.

The filter we added is extremely large so no flow rate or pressur drop is noted. I log pressure to the filter/regulator, and additionally to the carb.

Bill

Duane Eiskant II · 02-25-2012, 10:44 PM

Hey Bert, long time no see. I run the magnafuel pump and regulator on the mustang with the motorcraft carb. My by-pass pressure with the 16vt system pegs the 30lbs gauge everytime. I never turned it down, figured with the single needle and seat it couldnt hurt sending as much as possible to the front. I use the standard regulator but also use a #10 line (from the cell to the inlet of the carb) and never have had a problem with any of it. Now, because i use C11 fuel, and buy it in the pre package 5 gal pale i dont run a filter in the system anywhere, nor do i have the foam in the cell. 5 years so far so good, course now i jinxed myself and when i put it back together this year ill have a issue lol.... (hope not tho). Talk to you soon bud, good luck..
Lil Duane

bert powell · 02-25-2012, 11:57 PM

Thanks guys for the help! Cleaned it this morning (did not see anything) and made 5 passes today with no problems! Going to buy the filter before the regulator. Always good info on this site!

bert powell · 02-26-2012, 12:03 AM

Quote:

Originally Posted by Duane Eiskant II

Hey Bert, long time no see. I run the magnafuel pump and regulator on the mustang with the motorcraft carb. My by-pass pressure with the 16vt system pegs the 30lbs gauge everytime. I never turned it down, figured with the single needle and seat it couldnt hurt sending as much as possible to the front. I use the standard regulator but also use a #10 line (from the cell to the inlet of the carb) and never have had a problem with any of it. Now, because i use C11 fuel, and buy it in the pre package 5 gal pale i dont run a filter in the system anywhere, nor do i have the foam in the cell. 5 years so far so good, course now i jinxed myself and when i put it back together this year ill have a issue lol.... (hope not tho). Talk to you soon bud, good luck..
Lil Duane

Been probably ten years Duane! How are you doing? I don't know how your luck is but if I said I Had not had any issues my car would not run right again! Lol!

Paul Merolla · 08-12-2013, 10:14 AM

Quote:

Originally Posted by Bob Gullett

After installing my Magnafuel system I was having a problem with the large port regulator as well. Out of the blue the pressure would spike pegging my guage and of course blowing the needle and seat off the q-jet. I contacted magnafuel and they suggested along with the rear fuel filter to add an inline filter just before the regulator. Since I have done that never an issue again. They claim that the regulators are very sensative and the smallest particle of anything can cause the regulator not to work properly.

Bob - I'm having the same problem and will be adding a filter before the regulator. It happened when I was trying to start the car Thursday night to load up for Cedar Falls...filled # 7 cylinder with fuel, along with the crankcase. What filter did you use? Is it a finer mesh than the one at the rear of the car? Thanks.

Bob Gullett · 08-12-2013, 10:37 AM

http://www.summitracing.com/parts/mrf-mp-7010
http://www.summitracing.com/parts/mrf-mp-3013
This is the filter and fittings I use and Magnafuel recommends. I would recommend after installing it run the pump for a few seconds with the line from the carb removed into a container to flush anything out.

02-24-2012, 10:31 AM	#2
Bob Gullett VIP Member Join Date: Mar 2002 Posts: 1,106 Likes: 57 Liked 504 Times in 116 Posts	Re: Fuel pressure running off at the worst time After installing my Magnafuel system I was having a problem with the large port regulator as well. Out of the blue the pressure would spike pegging my guage and of course blowing the needle and seat off the q-jet. I contacted magnafuel and they suggested along with the rear fuel filter to add an inline filter just before the regulator. Since I have done that never an issue again. They claim that the regulators are very sensative and the smallest particle of anything can cause the regulator not to work properly. __________________ 68 Chevy11 327 F/S Last edited by Bob Gullett; 02-24-2012 at 10:35 AM.

02-24-2012, 10:35 AM	#3
philbilly Member Join Date: Aug 2011 Location: Demossville,KY Posts: 337 Likes: 0 Liked 0 Times in 0 Posts	Re: Fuel pressure running off at the worst time Bert I would check the reg. out not to mention I would check the bypass valve on the pump for some foreign object. If it held steady like your post then just out of the blue jumped up like that it is probably in your reg.

02-24-2012, 10:40 AM	#4
Bob Gullett VIP Member Join Date: Mar 2002 Posts: 1,106 Likes: 57 Liked 504 Times in 116 Posts	Re: Fuel pressure running off at the worst time To add to my post I did have a friend who had the same problem and magnafuel replaced the regulator no charge. __________________ 68 Chevy11 327 F/S

02-24-2012, 12:33 PM	#5
Bill Grubbs Member Join Date: Oct 2002 Location: Magnolia, Texas Posts: 416 Likes: 3 Liked 564 Times in 66 Posts	Re: Fuel pressure running off at the worst time Yes!!! the regulator is very sensitive to contamination. We fought this problem for most of the year last year, new fuel lines, filters, pump wiring, cleaned and serviced pump and regulator. We finally fixed it by adding a MagnaFuel filter just prior to the regulator (huge cudos to Robbie Ward @ MagnaFuel). We now have over 40 passes on the car with no problem. The filter we added is extremely large so no flow rate or pressur drop is noted. I log pressure to the filter/regulator, and additionally to the carb. Bill

02-25-2012, 10:44 PM	#6
Duane Eiskant II Senior Member Join Date: Dec 2001 Location: Alexandria, Va Posts: 501 Likes: 261 Liked 57 Times in 33 Posts	Re: Fuel pressure running off at the worst time Hey Bert, long time no see. I run the magnafuel pump and regulator on the mustang with the motorcraft carb. My by-pass pressure with the 16vt system pegs the 30lbs gauge everytime. I never turned it down, figured with the single needle and seat it couldnt hurt sending as much as possible to the front. I use the standard regulator but also use a #10 line (from the cell to the inlet of the carb) and never have had a problem with any of it. Now, because i use C11 fuel, and buy it in the pre package 5 gal pale i dont run a filter in the system anywhere, nor do i have the foam in the cell. 5 years so far so good, course now i jinxed myself and when i put it back together this year ill have a issue lol.... (hope not tho). Talk to you soon bud, good luck.. Lil Duane __________________ Duane Eiskant 1354 Stock/Super Stock

02-24-2012, 10:05 AM	#1
bert powell Member Join Date: Jul 2002 Posts: 243 Likes: 36 Liked 34 Times in 12 Posts	Fuel pressure running off at the worst time Guys, been aggravated with this problem on and off for a while. I have a GT/CA Camaro with a Qjet, Magnafuel 500 pump and the large 2 port reg. I added a fuel guage at the pump and was getting 26 psi at 12v. When I switch to 16v it would peg the guage over 30psi. So I tried to reduce the pressure and when it did come down the pump bypass would leak because it was screwed out too much. I cut two coils off the bypass spring and got the pressure at 26 psi at 16v. Reset the front regulator at 6 psi and went to test. First run fine. Second run, after the burnout the front pressure went to 12+psi. Got back to pit and cycled the pump, sat there at 6psi and would not move. Going to check the regulator for trash again but did not find any before. Anyone used the Magnafuel large 2 port regulator before without issues? Thinking about changing it. How much can I lower the pump pressure and still be safe, thinking about dropping it to 18psi. I had a carb fire trying to get the thing down the track before and would like to fix this permanently. Any ideas? Last edited by bert powell; 02-24-2012 at 10:07 AM. Reason: additional info

02-25-2012, 11:57 PM	#7
bert powell Member Join Date: Jul 2002 Posts: 243 Likes: 36 Liked 34 Times in 12 Posts	Re: Fuel pressure running off at the worst time Thanks guys for the help! Cleaned it this morning (did not see anything) and made 5 passes today with no problems! Going to buy the filter before the regulator. Always good info on this site!

08-12-2013, 10:37 AM	#10
Bob Gullett VIP Member Join Date: Mar 2002 Posts: 1,106 Likes: 57 Liked 504 Times in 116 Posts	Re: Fuel pressure running off at the worst time http://www.summitracing.com/parts/mrf-mp-7010 http://www.summitracing.com/parts/mrf-mp-3013 This is the filter and fittings I use and Magnafuel recommends. I would recommend after installing it run the pump for a few seconds with the line from the carb removed into a container to flush anything out. __________________ 68 Chevy11 327 F/S Last edited by Bob Gullett; 08-12-2013 at 10:45 AM.