Fuel Pressure Regulator w/ Return to Help Vapor Lock

I have loosely followed your other thread.

I know you mentioned a coupled different hoses between the tank and the hard line going up to the mechanical pump? I would be very susbitious of a leak there or blockage. It don't take much on the suction side of a pump, it may not leak fluid but it can suck air.

Then maybe try a reg airtex pump? I run them and have had good luck with them.

Here's a option for a return line.

I use a hemi vapor separator bolted to the fuel pump with a #57 orifice in the return line. Been this way since about 2003 and have driven the car hard at hi altitudes and very hi temperatures at hi altitudes and it has never let me down. Non of my stock fuel line was insulated. I drove it wide open for like 5 or more miles at a time out in Bonneville on the salt on a 95 degree days, 3 different years and it never ran out of fuel. Do you know how hard it is to drive 120 MPH for like 5 miles at a time?

Anyway here's pictures of my junk.
I included a picture of my gas tank connections, simple and sweet, not much chance of sucking air here.

If your car model ever came with a hemi, then you can order a pre bent 1/4" return line. Even if your car didn't come with a hemi I would call fine lines and ask them to bend up one for you in 1/4" just like your suction line and it will fit fine I'm betting.

Couple water pump bolts came loose and caused the rust stains. I haven't taken the time yet to pressure wash it off in this photo. Quality Tawan dipstick, no china crap on this motor. lol

I took it to Vegas last July, it was 110� pretty much 24/7. I idled it around for over a hour at time 3 times until I got smart and did my cruising at 6am so at least I could motor around with less traffic. One of many examples of extreme service is all I'm saying. Stock ain't always bad. Good thing my black car has AC otherwise it would be unbearable.
6AM the Vegas "strip" It was all mine, kinda.

Posted By: YO7_A66

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/04/14 09:50 PM

I made my own return fitting by using some brass fittings and a carb jet. I was told to locate the return fitting as high up on the fuel line as possible, then route back to the tank. I had these pieces laying around so once I was done, I started out testing with a couple of jet sizes and I ended up with a .052 jet as the oriface size for the return.
I took the brass barb fitting and tapped the inside for a 1/8npt thread. Then I took a 1/8npt plug and drilled/tapped it for a Holley style fuel jet. I started with a #60 and the idle psi was around 6.5psi. Then I swapped in a #52 jet and the idle psi went up to about 6-3/4psi or so. My electric fuel pump is rated at 7psi and I do not have a return regulator. (If I remmber correctly, the QF carbs are rated at 7-7.5psi at idle).

Attached picture 8165661-FuelReturnOrifice.JPG

Attached picture 8165661-FuelReturnOrifice.JPG

Posted By: cjskotni

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/04/14 10:03 PM

Quote:

I made my own return fitting by using some brass fittings and a carb jet. I was told to locate the return fitting as high up on the fuel line as possible, then route back to the tank. I had these pieces laying around so once I was done, I started out testing with a couple of jet sizes and I ended up with a .052 jet as the oriface size for the return.
I took the brass barb fitting and tapped the inside for a 1/8npt thread. Then I took a 1/8npt plug and drilled/tapped it for a Holley style fuel jet. I started with a #60 and the idle psi was around 6.5psi. Then I swapped in a #52 jet and the idle psi went up to about 6-3/4psi or so. My electric fuel pump is rated at 7psi and I do not have a return regulator. (If I remmber correctly, the QF carbs are rated at 7-7.5psi at idle).

Where did you put this fitting? Also, that brings up another question is that if I do add this filter/seperator, it is just acting like a tee in the fuel line. Won't this 1/4" return line cause a signicant drop in fuel pressure to the carb unless you do restrict it (like with the jets)??

Posted By: Steve Bryant

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/04/14 10:04 PM

On my Barracuda, the fuel pickup only had one line as your does that ran to the front of the car into the fuel pump. The fuel pump connected to the vapor separator which had one 5/16 line that ran up to the carb and one 1/4 line that ran to the back of the car and to the canister up in the trunk recess. In my setup, my gas tank has four lines that ran into a canister filter in the rear and one line ran up front to the vapor canister. I ripped all that and removed the vapor canister up front, removed the 1/4 return line and put a check valve on the open line that ran into the trunk recess. When I go to connect mine back up, I will buy a new vapor filter up front and I will run a new 1/4 line back to the trunk recess into that hose where I added a check valve.

I do not have part numbers but YearOne has replacements for all the parts I have mentioned and that is where I will get mine when I decide to run a new return.

Posted By: cjskotni

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/04/14 10:12 PM

Quote:

On my Barracuda, the fuel pickup only had one line as your does that ran to the front of the car into the fuel pump. The fuel pump connected to the vapor separator which had one 5/16 line that ran up to the carb and one 1/4 line that ran to the back of the car and to the canister up in the trunk recess. In my setup, my gas tank has four lines that ran into a canister filter in the rear and one line ran up front to the vapor canister. I ripped all that and removed the vapor canister up front, removed the 1/4 return line and put a check valve on the open line that ran into the trunk recess. When I go to connect mine back up, I will buy a new vapor filter up front and I will run a new 1/4 line back to the trunk recess into that hose where I added a check valve.

I do not have part numbers but YearOne has replacements for all the parts I have mentioned and that is where I will get mine when I decide to run a new return.

If you run the fuel return line to the vapor seperator by the tank, how will your tank vent? Wouldn't you start getting a vaccum lock situation as your tank will not be able to pull in air to displace the gas your pump removes from it???

Posted By: Challenger 1

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/04/14 10:30 PM

Quote:

On my Barracuda, the fuel pickup only had one line as your does that ran to the front of the car into the fuel pump. The fuel pump connected to the vapor separator which had one 5/16 line that ran up to the carb and one 1/4 line that ran to the back of the car and to the canister up in the trunk recess. In my setup, my gas tank has four lines that ran into a canister filter in the rear and one line ran up front to the vapor canister. I ripped all that and removed the vapor canister up front, removed the 1/4 return line and put a check valve on the open line that ran into the trunk recess. When I go to connect mine back up, I will buy a new vapor filter up front and I will run a new 1/4 line back to the trunk recess into that hose where I added a check valve.

I do not have part numbers but YearOne has replacements for all the parts I have mentioned and that is where I will get mine when I decide to run a new return.

Like Cab said above, only the hemi and 440/6paks got the vapor separator up front on the fuel pump and the return line to the sending unit. Now all aftermarket sending units have the return nipple. The return line was not very common on mopars. But it can be used and is the best way to run a return line on any motor and on most cars.

The vent separator in back(which has a different purpose than the one in front)was setup to join four vent hoses into one container where the fumes/liquid could separate/drain back into the tank. The four vent lines insures that the tank is vented even when it is full and the car is not parked level. The rear separator also insures that gas won't run out of your tank on the ground if it's parked full out of level.

The vent separator in the rear has a line that runs up front to the engine compartment up on top of the motor.(It's important to end on top of the motor because it's higher than the tank) Then gas and fumes will never spill out or be smelled in a closed garage.
There's nothing wrong or anything that can be improved from the factory venting. So I highly recommend to run the entire factory vent setup for your car model. This venting that I'm talking about has nothing to do with the fuel pump or the front mounted vapor separator.

The only thing I could see doing away with is the charcoal canister up front. So instead of terminating the vent line to it, you connect it to the breather on the valve cover just like they did it in 1971. My 71 is setup like that and it's always inside and I never smell gas.

I've replaced entire fuel systems here lately on 2 cars.

Posted By: Steve Bryant

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/04/14 10:35 PM

The four lines there ran right back into the tank so it vented quite well. Of course I am not 100% sure why my setup had this since it was just a 318 on an E-Body.

Posted By: Challenger 1

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/04/14 10:57 PM

Notice the brass or copper tips on the vent lines. I guess to prevent sparks?

See how the separator is positioned, all vent lines enter the bottom where it can drain back and the actual vent nipple where the vent line attaches is up top.

Actually I believe the 1/4" return was clamped to the other 2 lines from the factory and not in the bolted on clamps, they have these s hooks that hold the line to the other lines. This is the only place I put all three in on e clamp on this car, they don't really fit.

Posted By: Cab_Burge

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/04/14 11:13 PM

The four vent lines in the tank to each corner are to ensure that all the air is pushed out when filling the tanks on those cars that had that system, my 1971 Duster was one of them. It took the last 3 or 4 gallons very slowly, just like my 2006 Ram 3500 CTD does on the last 2 gallons

Posted By: Challenger 1

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/04/14 11:48 PM

Quote:

The four vent lines in the tank to each corner are to ensure that all the air is pushed out when filling the tanks on those cars that had that system, my 1971 Duster was one of them. It took the last 3 or 4 gallons very slowly, just like my 2006 Ram 3500 CTD does on the last 2 gallons

In other words, it allows the tank to totally vent.

Posted By: dogdays

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/04/14 11:54 PM

Some of the confusion is due to incorrect terminology.

The VAPOR SEPARATOR is to keep vapor out of the carburetor. That's what the filter with the extra fitting is for. I believe that if one looks up into the smaller tube coming off the filter, one sees a smaller hole (orifice) where the tube connects to the filter body. The return line conducts the vapor and whatever liquid fuel flowing through the orifice, back into the fuel tank. Otherwise, where would it go?

Now on to the back of the car. In 1971, maybe earlier, Federal regulations required new cars to control emissions of fuel evaporating from the gas tank. This is called EVAPORATIVE EMISSIONS CONTROL. It controls evaporative emissions by collecting the vapor that exists in the top of the tank and catching it in either a larger container where the evaporated fuel can condense and run back into the tank, or else into a charcoal canister that is plumbed to the engine intake, so that the evaporated fuel is eventually burned by the engine. This had NOTHING to do with preventing vapor lock, and was not primarily intended to allow the complete filling of the tank. It was a response to a Federal mandate.

My 1972 Nova had the charcoal canister. My 1971 D100 had a simple vent line going to a larger segment of tube, which I think had an overflow that went through the floor.

Starting whenever the Federal mandate went into effect, gas caps were NO LONGER VENTED.

There is nothing about the evaporative emissions control system that harms performance. (Well, maybe it adds a pound or two of extra weight.) Removing it only demonstrates one's ignorance.

R.

Posted By: ahy

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/05/14 02:05 AM

Quote:

Some of the confusion is due to incorrect terminology.

The VAPOR SEPARATOR is to keep vapor out of the carburetor. That's what the filter with the extra fitting is for. I believe that if one looks up into the smaller tube coming off the filter, one sees a smaller hole (orifice) where the tube connects to the filter body. The return line conducts the vapor and whatever liquid fuel flowing through the orifice, back into the fuel tank. Otherwise, where would it go?

Now on to the back of the car. In 1971, maybe earlier, Federal regulations required new cars to control emissions of fuel evaporating from the gas tank. This is called EVAPORATIVE EMISSIONS CONTROL. It controls evaporative emissions by collecting the vapor that exists in the top of the tank and catching it in either a larger container where the evaporated fuel can condense and run back into the tank, or else into a charcoal canister that is plumbed to the engine intake, so that the evaporated fuel is eventually burned by the engine. This had NOTHING to do with preventing vapor lock, and was not primarily intended to allow the complete filling of the tank. It was a response to a Federal mandate.

My 1972 Nova had the charcoal canister. My 1971 D100 had a simple vent line going to a larger segment of tube, which I think had an overflow that went through the floor.

Starting whenever the Federal mandate went into effect, gas caps were NO LONGER VENTED.

There is nothing about the evaporative emissions control system that harms performance. (Well, maybe it adds a pound or two of extra weight.) Removing it only demonstrates one's ignorance.

R.

The 3 prong filter has an orifice so it does not drop fuel pressure too much. Its supposed to be around .050". Running the return back to the 1/4 nipple on the sender should be fine. In normal operation it will simply dump some fuel back in the tank and the circulation will keep things cooler to help prevent vapor lock. If the line gets hot and vapor does form, the separator will direct it back to the tank also. By the time it makes it back, it may cool and turn back to liquid but either way you are at least helping prevent vapor in the engine compartment.

Posted By: cjskotni

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/05/14 02:16 AM

If I got something like this:

Does it have 3/8" nipples for the in/out so it will work well with my fuel line? Also, how does this thing bolt to the engine so it doesn't bounce around?

Or do I need this style since my car is a 73?

Posted By: Challenger 1

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/05/14 02:29 AM

Quote:

If I got something like this:

Does it have 3/8" nipples for the in/out so it will work well with my fuel line? Also, how does this thing bolt to the engine so it doesn't bounce around?

That's the hot ticket, be sure there is a restriction for the return. No you can't use 3/8".

5/16" is the correct outlet size with a 3/8 inlet on the fuel pump. That how the fuel pump works best.

Everyone is hung up on 3/8, you don't need 3/8 from the pump to the carb. Even 3-2s or a hemi screaming at full song, as evidence of this filter/separator is only supplied by 5/16. It's a short run and 5/16" is more than enough.

Posted By: 451Mopar

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/05/14 10:50 AM

I used the Carter performance pump, and Hemi vapor separator, and did not have any fuel problems.
The reproduction vapor separator is expensive, I think $50, but it is setup for 3/8" lines. The fuel filters with vapor port I think are 5/16" fuel line, but only cost a few bucks. Really, you could just add a "T" to the fuel line before the carb, and install a restriction in the line that returns to the tank. You just want to maintain a minimum steady flow of fuel through the fuel pump and lines.

Posted By: YO7_A66

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/05/14 12:32 PM

"" Really, you could just add a "T" to the fuel line before the carb, and install a restriction in the line that returns to the tank. You just want to maintain a minimum steady flow of fuel through the fuel pump and lines""

The brass fitting that I shown in my previous reply is in this "T". 3/8" in and 3/8" out and I can adjust the flow back to the tank with a simple jet change. It is not stock but it flows well.

Attached picture 8166344-FuelT.JPG

Posted By: cjskotni

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/07/14 07:57 PM

Well I pulled the fuel pump and checked the push rod and compared it to the new rod I just got from Mancini. The rod is the exact same length as the new one with no wear I can discern. I am guessing a worn rod isn't my issue. :-(

If this isn't vapor lock, I am open to suggestions on what else to check...

As far as the hemi/440-6 setup, how did the factory hook all that up? Was there a hard line from the pump outlet to the vapor separator inlet? Did you just use a barb on the outlet and run rubber line to the separator? Where does that little tab on the vapor separator mount on the engine?

Thanks!

Posted By: Challenger 1

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/07/14 08:05 PM

Bummer it wasn't the push rod.

It bolts to the fuel pump, like I said above. All barbed fittings and rubber hoses.

One is suction and the smaller the return. The upper line is my gas tank vent, it'll connect to the breather on the valve cover. Get it??

Posted By: cjskotni

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/08/14 12:44 AM

Thanks for the pictures! I ordered the return line, vapor separator, and a hemi fuel pump (3/8" inlet). I am going to ditch the Holley just in case that is the issue.

Is this going to be a pretty sure way to fix this vapor lock issue? Is there anything else I need to do to help this or will the return line pretty much get rid of it?

Thanks!

Posted By: cjskotni

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/11/14 12:25 PM

I should have some of the parts creeping in here soon...

Do I need/should I use any type of fuel filter between the separator and the carburetor? Will this separator be enough to strain the fuel and keep the carb from getting trash in it?

I also thought of why the 73+ style VS has the funky bracket as those years originally had the passenger side exit on the WP housing. I am guessing this would interfere with the placement of the VS right on the pump there. Luckily I switched to the driver's side WP housing on mine years ago to make it easier to find an aluminum radiator that would work.

If this doesn't fix this stalling issue, I think I am going to

this car and collect insurance money!

Posted By: DAYCLONA

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/11/14 03:45 PM

Did you ever check to see if fuel is drippling in the secondary venturis while the car is ideling after a few minutes?

Mike

Posted By: cruzin

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/11/14 07:02 PM

I'm a little late to the party however, if your hood clearance permits, consider adding a carb spacer/insulator.

Another simple solution is "T" off of the rear, secondary carb feed line. This added outlet coming off the carb feed line can then either be ran back to the 1/4" port on the sending unit or use a fuel filter with an added port such as Fram filter G3499 and run the return to the filter. If you run it back to the tank, this provides a loop or circulating fuel system.

Attached picture 8172967-carbfeed.jpg

Posted By: dogdays

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/11/14 09:14 PM

Putting an electric pump back by the gas tank, shielded from exhaust heat, is the best way to eliminate vapor lock. Remove the mechanical pump. Run a return line to move a little fuel all the time.

R.

Posted By: cjskotni

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/12/14 01:55 AM

I am not sure if I am going to be able to get a hard line to fit from the VS to the carb inlet as my application is non-oem with a high rise intake and the dual fuel line for my Holley. Would it be safe to run just rubber hose from the VS outlet to the carburetor fuel fitting...maybe 18" or so?

---------------------------------------------------------------------

Quote:

Did you ever check to see if fuel is drippling in the secondary venturis while the car is ideling after a few minutes?

I have not as I pulled the pump to check the push rod and the car is laid up now until I get this fuel system put back together. Why am I checking for this?

Quote:

I'm a little late to the party however, if your hood clearance permits, consider adding a carb spacer/insulator.

I have a 1/4" composite carb gasket so that should help here.

Quote:

Putting an electric pump back by the gas tank, shielded from exhaust heat, is the best way to eliminate vapor lock. Remove the mechanical pump. Run a return line to move a little fuel all the time.

Never gonna happen on this car. I know electric fuel pumps can combat vapor lock but they can add a whole other host of problems. I am going to stick with mechanical on this car. I am adding the return line though.

Posted By: 340SHORTY

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/12/14 02:06 AM

having a dual inlet carb makes it easy to fab an inexpensive return line. dont try to reinvent the wheel.

Posted By: davenc

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/12/14 05:44 AM

I also do not suspect vapor lock is your cause. Did you ever have a chance to reproduce the problem, and view how much fuel is in the bowl via the sight plug?

Every car is different, and my fuel system is not stock, but I do run a mechanical pump with no return line, and drive my car in the heat without having any problem similar to what you are experiencing. Perhaps I'm just lucky....

I do know how frustrating it is to get the car stuck by the side of the road (I had an electrical ignition issue that put me thru a similar situation for months before I found it). Now that the heat is on in NC, have you ever tried to let the car idle at your house for an extended period, then shut it down for 10-15 minutes, then try a restart? You could load the motor against the converter while in gear to generate additional heat under the hood.

Posted By: 71rm23

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/12/14 08:06 AM

Quote:

Bummer it wasn't the push rod.

It bolts to the fuel pump, like I said above. All barbed fittings and rubber hoses.

One is suction and the smaller the return. The upper line is my gas tank vent, it'll connect to the breather on the valve cover. Get it??

Gary:
Can you post a picture of the lines hooked up in the engine compartment? Ill be doing that part soon. I only have 2 lines under my hood(if my mind serves me right) with new stainless. My car is a 71 RR.

Thanks!

Posted By: Steve Bryant

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/12/14 03:11 PM

Challenger_1 , many thanks for posting these photos. Your build is exceptional and the layout really helps to explain the fuel and return process.

Posted By: cjskotni

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/15/14 09:08 PM

Ok guys here is an update. I got a reproduction hemi fuel pump (3/8" inlet) and basically replicated the factory setup. I had to rework the hard line from the vapor separator to the carburetor but I think I got a working solution. I am not crazy about running a rubber hose right around the distributor.

I measured the fuel return orifice with a set of drill bits and found it right at 7/64" which comes out to ~.102 inches. Doing the math, this comes out to around 12.2% of the cross section of the main 5/16" outlet. Would this be too large or am I ok?

I pulled the sending unit and it looks brand new in every way. Sock is perfect and no corrosion anywhere. I had to re-open the return nipple to plumb in my line when it arrives this week. Once I have the return line and the AN to 5/16" nipple, I should be able to start testing this out.

Is there anything else I should do while the car is 'down' to help combat this possible vapor lock?

Thanks for the help so far.

Posted By: 340SHORTY

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/15/14 10:30 PM

I hear a .050/.060 opening is optimal

Posted By: MoparMarq

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/16/14 03:13 AM

Don't blame you about wanting to avoid rubber hose around the distributor. On mine, I was concerned about the heat into the fuel line also. Same separatot setup as yours now is. I bent up a fuel feed line from the outlet of the separator to the fuel pressure regulator near the carb from 5/16" brake line. Put the bends in it to look semi-factory with an inexpensive tubing bender hand tool. Then ran a 3/8" hose around it full length to provide some insulation for the hard line. Split the hose along its length to get it around the hard line and then placed cable ties at evenly spaced intervals to hold it in place. It's not pretty, but of course aluminum transmits heat better than steel, so I thought it might be necessary.

Attached picture 8177399-CarbFuelLine_1.jpg

Attached picture 8177399-CarbFuelLine_1.jpg

Posted By: cjskotni

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 06/26/14 01:32 AM

Here's an update. I had the wrong line shipped to me from InlineTube so I am now waiting on the correct line to get here. One the plus side, InlineTube mde it right and sent out the correct line without any issues. It's good to deal with vendors who don't yank you around.

Since the opening on the fuel return port on my vapor separator is around .110" which seems to be larger than the recommended .060" people here have recommended, I got a piece of 1/4" brass rod and drilled out a 1/16" hole which is right around .0625". I inserted this restrictor is a piece of 1/4' fuel hose so I'm ready for my return line when it gets in.

I custom bent a 5/16" SS hard line from the VS outlet to the carburetor feed line inlet. I am hoping heat won't be an issue as this line does not touch anything at all so no direct heat transfer...

Attached picture 8187679-20140625_185034_resized.jpg

Posted By: cjskotni

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 08/03/14 01:21 AM

Well guys here is a update as I finally made some progress after actually having a free day to sit down and work on this.

I had custom bent a 5/16 hard line from the vapor separator outlet to the carb inlet and had everything ready to go. Well I go to put the alternator on and sure enough that line running up the side of the WP housing was making it where I couldn't rotate the alternator far enough down to get the belts on its pulley.

Fast forward a few weeks later and I bent another hard line and ran it in front of the WP housing and beside the distributor to connect to the carb inlet.

After cranking it over off and on for about a minute, I got fuel pressure on the gauge and it fired right up! Everything seems fine so far but I won't know if the issue if fixed until I drive it an get it nice and hot. I did notice my fuel pressure gauge on the carb inlet fluctuates wildly now as in I can't see where it reads as it bounces back and forth so quickly! Is this normal now that I have a return line to bleed off the pressure from each 'pump'? It seems to just bounce back and forth while running between the entire range of 0-15psi but this could be because of needle momentum.

Do I have anything to worry about based on the fuel pressure gauge behavior? Of course it's rainy here all weekend so can't take it out of the garage yet to test.

Posted By: RapidRobert

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 08/03/14 02:26 AM

The 0-15 bounce ain't right. You might clamp the return line (gently) with a pair of pliers & see what that does to it

Posted By: meepmeep70

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 08/03/14 01:06 PM

Quote:

The 0-15 bounce ain't right. You might clamp the return line (gently) with a pair of pliers & see what that does to it

correct type of fuel gauge? does it bounce from start up?,i had a gauge do that once it got hot, was an liquid filled type, once hot couldn't read it, changed out to a no liquid filled all good.

Posted By: cjskotni

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 08/16/14 04:30 PM

I finally got the gumption to fire the Charger up and take it for a 10 mile or so drive to get a feel for the new fuel system.

I went ahead and took a video of the fuel pressure gauge at idle and took a bit of a closer look. It appeared to me to jump from 0-10psi at idle so I'm guessing the actual pressure is somewhere around 5psi or so? Here is the video slowed down 8x.

!!Video Here!!

Outside temp is around 75 degrees so not really hot but I drove it to the gas station to fill her up (premium less than $4/gal here now :-)) and drove back home. In the garage I idled it about 7-8 minutes with the A/C on, cut it off for 30 minutes, and then fired back up and idled for 5 more minutes with the A/C on. So far so good...car ran beautifully and acted like it wanted to pull itself down the highway.

Can any of you guys running the factory type vapor separator and return line setup comment on my pressure reading? Does this look 'normal' for my setup?

Thanks guys!

Posted By: RapidRobert

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 08/17/14 03:08 AM

I watched the video & a light bulb came on, I have ran into that once decades ago & it was a pump (valve sealing) issue!

Posted By: cjskotni

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 08/17/14 01:18 PM

Quote:

I watched the video & a light bulb came on, I have ran into that once decades ago & it was a pump (valve sealing) issue!

This pump is brand new! I figured the pressure swings were because of the return line bleeding off pressure from each pump cycle.

Would reading that gauge while cranking the car be accurate on what it's doing while running? When I am cranking the car the needle jumps up to around 5psi and then just drops back. Once about every second which I'm guessing is from each pump cycle.

I will try to get a helper to crimp the return line and see if I can take a video of what happens to the fuel pressure.

I was just hoping somebody here has this setup and had monitored fuel pressure before and could tell me if this is normal.

Posted By: RapidRobert

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 08/17/14 02:49 PM

Alright, other possibilities would be that the gauge is bad or that the return line is bleeding off to much psi (dont remember how big an orifice you used but I dont think it was outrageous). yes I would crimp the return line with some pliers and a rag to protect the neoprene from the jaw serrations & that'd elim it in 1 minute. Keep us posted

Posted By: cjskotni

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 08/17/14 02:58 PM

RapidRobert:

Quote:

Since the opening on the fuel return port on my vapor separator is around .110" which seems to be larger than the recommended .060" people here have recommended, I got a piece of 1/4" brass rod and drilled out a 1/16" hole which is right around .0625". I inserted this restrictor is a piece of 1/4' fuel hose so I'm ready for my return line when it gets in.

I custom bent a 5/16" SS hard line from the VS outlet to the carburetor feed line inlet. I am hoping heat won't be an issue as this line does not touch anything at all so no direct heat transfer...

Posted By: cjskotni

Re: Fuel Pressure Regulator w/ Return to Help Vapor Lock - 08/24/14 09:28 PM

Ok I am hoping I can put this thread to bed soon and move on with my life...

I got a buddy to crimp the return line while Charger was idling and the pressure stabilized right between 7-10 psi according to my gauge. We spent some time looking at the gauge bouncing as we slowly crimped the return line shut and it seemed the pressure would start to stabilize and rise as the line was crimped more. We also spent a lot of time staring down the gauge as the car idled and we came to the consensus that it is bouncing from 0-6 psi.

I know the 7-10 psi is high but since this pump was designed for the 440-6/hemi applications, I am guessing it is designed for that return line to bleed off the excess pressure?

Either way, I took the car out and drove it a good 20 miles or so in mid 80's temp day so I know it was good and hot. Even after most of that drive, I was able to give it some gas and break the tires free at 30 mph pretty easily so the engine is still pulling strong. I drove it home and parked it, let it sit for 20 minutes, and it fired up and idled fine with A/C on so this look promising.

I know you guys are probably tired of this thread but maybe somebody combatting a similar issue can make use of my experience as I have done with so many others here.

Fuel Pressure Regulator w/ Return to Help Vapor Lock