Fuel Pressure Regulator What PSI Should I set it at? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

petey-pablo · 10-21-2009, 06:37 AM

Hello I was wondering if anyone new what was the best PSI to set my Fuel Pressure Regulator at? I think my motor is getting too much fuel it back fires and wants to stall when I punch it very hard start when cold sometimes it even catches fire

I am running a Proform 750 cfm, 4-Barrel Race Series Carburetor and a Holley Blue Electric Fuel Pump & Holley Fuel Pressure Regulator, MSD Pro-Billet Distributor. My motor is a 454BB with a Mild Cam Not sure what cam I have.. I also have a Fuel Pressure Gauge and I am currently at 7PSI.. Truck ran fine before I swaped out the old Fuel Pressure Regulator so my guess would be I didn't set it right since it didn't have a Fuel Pressure Gauge I don't know what it was set at I just went by looks, I tried to match it up as best as I could..
Thanks Pablo

Tx Firefighter · 10-21-2009, 06:41 AM

Popping fire back through the carb is timing mis-adjustment.

cdowns · 10-21-2009, 08:02 AM

depends on your carb most are between 5-7lbs of pressure,you do have a gauge on the regulator ?

i agree the spiting up thru carb is normally a timing issue

**truckdude239** · 10-21-2009, 08:47 AM

5-8 psi

rico7769 · 10-21-2009, 09:09 PM

play with 5-7 and check the carb specs. I run 7.5 with no issues. Any higher and I get flooding issues. Backfires are generally related to timing though. My two cents

QKENUF4U · 10-21-2009, 11:43 PM

ive always heard/read 7psi max.....

70duramax · 10-21-2009, 11:44 PM

backfire through carb = timing issue
backfire through the pipes = fuel issue

67chevemall · 10-22-2009, 11:32 AM

I think the stock mech fuel pump is 4.5 ?

petey-pablo · 10-22-2009, 04:02 PM

Aww you guys are awsome I would have never guessed it was timing issue, Because I have never messed with the dizzy.... I went out and tried to fire it up and poof it blew backfired and set fire again then I checked the dizzy and it was loose what do you know so I turned it just alittle and wow it started rite up thanks again guys.........Now I am off to the mechanic so he can set my timing.......

Amber1982 · 09-01-2018, 12:40 PM

Hi there! On the same topic, different concern... I have recently converted the fuel pump on my 77 GMC Vandura to an electric. Looking at the pressure specs, I wonder if I just bought into a useless fuel pump! The clerk at Autozone sold me one that is rated for 2-4 PSI and tried to send me off with a regulator that only went up to 4 as well.
The pump did get the van running, and able to be driven to work, but I won't feel comfortable that it is done and ready for a real adventure until I put the regulator in.
I am pretty new to this van, it has been a lot of fun and learning for me!
Would it be wise to get a stronger pump to at least have on hand should the current one crap out while I am in the middle of nowhere?

geezer#99 · 09-01-2018, 01:46 PM

Tee a fuel pressure gauge into the fuel line to the carb and see what the pressure is when it’s running.
I’ve never seen an electric pump rated so low.
4 psi won’t hurt anything.
Your carb likely won’t handle more than 6 psi anyway.
The regulator might of been a return style. Highly recommended for an electric pump. They like to heat up and quit if they’re deadheaded.
What made you think you needed an electric pump anyway?

Amber1982 · 09-01-2018, 08:58 PM

What made you think you needed an electric pump anyway?[/QUOTE]
Posted via Mobile Device

The mechanical pump went out- in replacing it, the cam arm was stuck down and could not be pulled up. Once I got it loosened enough to at least spin a little, it felt slightly bent.

mike16 · 09-02-2018, 02:14 AM

back firing through the carb is a lean fuel condition. It may be timing but in the context of a fuel related issue its an indication of a lean condition.

and according to .......Doug Roe's Rochester carburetors, published way back in 1981 by HP Books....... on pg 116 it says between 4 and 6 psi. It also states several times that pressure should never exceed 6 psi and can be operated down ward to 2 psi under rough terrain conditions.

**'68OrangeSunshine** · 09-02-2018, 11:45 PM

Edelbrocks like 5.5 PSI.
I know nothing about Proforms.

10-21-2009, 06:37 AM	#1
petey-pablo "THE GREEN GOBLIN" Join Date: Mar 2008 Location: Fremont Ca. Posts: 1,025	Fuel Pressure Regulator What PSI Should I set it at? Hello I was wondering if anyone new what was the best PSI to set my Fuel Pressure Regulator at? I think my motor is getting too much fuel it back fires and wants to stall when I punch it very hard start when cold sometimes it even catches fire I am running a Proform 750 cfm, 4-Barrel Race Series Carburetor and a Holley Blue Electric Fuel Pump & Holley Fuel Pressure Regulator, MSD Pro-Billet Distributor. My motor is a 454BB with a Mild Cam Not sure what cam I have.. I also have a Fuel Pressure Gauge and I am currently at 7PSI.. Truck ran fine before I swaped out the old Fuel Pressure Regulator so my guess would be I didn't set it right since it didn't have a Fuel Pressure Gauge I don't know what it was set at I just went by looks, I tried to match it up as best as I could.. Thanks Pablo __________________ Petey-pablo "THE GREEN GOBLIN" 1972 Cheyenne 10 Short Fleet Side Front 2.5inch Spindles with 2inch Springs Rear 4inch drop Springs. 454BBC TH400,Posi 1971 Cheyenne 10 Long Fleet Side 454BBC TH350,Posi Sold Drive it like you stole it! Petey-pablo@sbcglobal.net

10-21-2009, 06:41 AM	#2
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Re: Fuel Pressure Regulator What PSI Should I set it at? Popping fire back through the carb is timing mis-adjustment. __________________ I'm on the Instagram- @Gearhead_Kevin

10-21-2009, 08:02 AM	#3
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Fuel Pressure Regulator What PSI Should I set it at? depends on your carb most are between 5-7lbs of pressure,you do have a gauge on the regulator ? i agree the spiting up thru carb is normally a timing issue __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

10-21-2009, 08:47 AM	#4
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,217	Re: Fuel Pressure Regulator What PSI Should I set it at? 5-8 psi __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

10-21-2009, 09:09 PM	#5
rico7769 Hybrid67 Join Date: Jan 2009 Location: Martinez, GA Posts: 195	Re: Fuel Pressure Regulator What PSI Should I set it at? play with 5-7 and check the carb specs. I run 7.5 with no issues. Any higher and I get flooding issues. Backfires are generally related to timing though. My two cents __________________ Keep em' Running! All show.....no go

10-21-2009, 11:43 PM	#6
QKENUF4U Senior Member Join Date: Jan 2005 Location: SUNNY WARM BIKE RIDING COTTONWOOD ARIZONA Posts: 2,097	Re: Fuel Pressure Regulator What PSI Should I set it at? ive always heard/read 7psi max.....

10-21-2009, 11:44 PM	#7
70duramax Registered User Join Date: Dec 2008 Location: morrisdale pa Posts: 46	Re: Fuel Pressure Regulator What PSI Should I set it at? backfire through carb = timing issue backfire through the pipes = fuel issue

10-22-2009, 11:32 AM	#8
67chevemall Registered User Join Date: Apr 2003 Location: NB Posts: 3,367	Re: Fuel Pressure Regulator What PSI Should I set it at? I think the stock mech fuel pump is 4.5 ? __________________ 1968 Chevy C10 307 3ott fleetside 1967 Chevy C/10 V8, 3spd, fleetside lwb.Sold 1967 Chev C/10 step, 383, M21. SOLD

10-22-2009, 04:02 PM	#9
petey-pablo "THE GREEN GOBLIN" Join Date: Mar 2008 Location: Fremont Ca. Posts: 1,025	Re: Fuel Pressure Regulator What PSI Should I set it at? Aww you guys are awsome I would have never guessed it was timing issue, Because I have never messed with the dizzy.... I went out and tried to fire it up and poof it blew backfired and set fire again then I checked the dizzy and it was loose what do you know so I turned it just alittle and wow it started rite up thanks again guys.........Now I am off to the mechanic so he can set my timing....... __________________ Petey-pablo "THE GREEN GOBLIN" 1972 Cheyenne 10 Short Fleet Side Front 2.5inch Spindles with 2inch Springs Rear 4inch drop Springs. 454BBC TH400,Posi 1971 Cheyenne 10 Long Fleet Side 454BBC TH350,Posi Sold Drive it like you stole it! Petey-pablo@sbcglobal.net Last edited by petey-pablo; 10-22-2009 at 04:03 PM.

09-01-2018, 12:40 PM	#10
Amber1982 Registered User Join Date: Sep 2018 Location: Boise Posts: 2	Re: Fuel Pressure Regulator What PSI Should I set it at? Hi there! On the same topic, different concern... I have recently converted the fuel pump on my 77 GMC Vandura to an electric. Looking at the pressure specs, I wonder if I just bought into a useless fuel pump! The clerk at Autozone sold me one that is rated for 2-4 PSI and tried to send me off with a regulator that only went up to 4 as well. The pump did get the van running, and able to be driven to work, but I won't feel comfortable that it is done and ready for a real adventure until I put the regulator in. I am pretty new to this van, it has been a lot of fun and learning for me! Would it be wise to get a stronger pump to at least have on hand should the current one crap out while I am in the middle of nowhere?

09-01-2018, 01:46 PM	#11
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,517	Re: Fuel Pressure Regulator What PSI Should I set it at? Tee a fuel pressure gauge into the fuel line to the carb and see what the pressure is when it’s running. I’ve never seen an electric pump rated so low. 4 psi won’t hurt anything. Your carb likely won’t handle more than 6 psi anyway. The regulator might of been a return style. Highly recommended for an electric pump. They like to heat up and quit if they’re deadheaded. What made you think you needed an electric pump anyway?

09-01-2018, 08:58 PM	#12
Amber1982 Registered User Join Date: Sep 2018 Location: Boise Posts: 2	What made you think you needed an electric pump anyway?[/QUOTE] Posted via Mobile Device The mechanical pump went out- in replacing it, the cam arm was stuck down and could not be pulled up. Once I got it loosened enough to at least spin a little, it felt slightly bent.

09-02-2018, 02:14 AM	#13
mike16 Registered User Join Date: Dec 2009 Location: bisbee, arizona Posts: 1,529	Re: Fuel Pressure Regulator What PSI Should I set it at? back firing through the carb is a lean fuel condition. It may be timing but in the context of a fuel related issue its an indication of a lean condition. and according to .......Doug Roe's Rochester carburetors, published way back in 1981 by HP Books....... on pg 116 it says between 4 and 6 psi. It also states several times that pressure should never exceed 6 psi and can be operated down ward to 2 psi under rough terrain conditions.

09-02-2018, 11:45 PM	#14
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,063	Re: Fuel Pressure Regulator What PSI Should I set it at? Edelbrocks like 5.5 PSI. I know nothing about Proforms. __________________ Every 25 years I like to rebuild that 292, whether it needs it or not.



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