Adding a fuel pressure regulator

The language in the Edelbrock 1406 manual about Ford 302’s having too high fuel pressure got me wondering. The manual says the carb doesn’t want to see 6psi or more and recommends 5.5psi.

I looked in the shop manual and for the fuel pump specs for the V8 engines it says the static pressure at 500rpm is 4.5 - 6.5, which sounds like what the Eddy manual was talking about.

Is there anything wrong with adding a simple fuel pressure regulator (one port in, one out, and a dial to adjust psi) inline between the pump and carb? That’s the place for it, right? Is there any potential problem, or potential benefit, in doing this?

I should have asked sooner, I got gung-ho a couple weeks ago and bought a regulator already. It was only like $25 so if it turns out I screwed up, I won’t cry about it.

I’m hoping this is the answer to why at idle I’m still getting an intermittent loss of rpm and puff sound from the exhaust.

I want to hit the garage tonight and at the very least install the fuel filter I already picked up, there’s none on there right now unless its the tiny metal piece that’s screwed into the carb where the fuel line connects-- seems too small to me to be a fuel filter… which is really bad news, I know. I dont know how long the previous owner operated it like that. Also I would ideally like to throw the regulator in as well, just do it all at once and see where that leaves me.

Any input is appreciated.

Mission not accomplished. The fuel filter I bought when I got the fuel pump (second day I owned the car and back when I was even more noob than I am now) is the stock one which is threaded to screw into the factory carb that I don’t have. Gotta pick one up tomorrow. My neighborhood shop (CarQuest) has clear plastic ones but not clear glass. Is there anything wrong with a clear plastic one, or a compelling reason to go for glass instead? I imagine plastic melting and glass breaking, but I assume neither is the case or people wouldn’t manufacture em or use em, right?

I had a pressure regulator on my 302 I ran it at 5.5 psi. Never had any problems with fuel. Now as far as a filter I used a metal type. Glass is helpful if you want to see how “clean” you filter is. If you worry about the glass breaking or plastic melting rethink how you plan on mounting the filter. Oh, try to stay away from using a rubber fuel line. They can break down over time and cause more problems. I don’t think a regulator is the answer to your idle problem. How many miles are on your car? Check your fuel psi with a gauge. If its low you might have a worn cam lobe that operates the fuel pump. If thats the case go with a electric pump and regulator and use a block off plate where the stock pump is located.

Someone might know better that I do if they have had this type of problem. I hope this helps. Good Luck. :thumbup:


Thanks for the input!

62k miles. I do want to check the fuel pressure though, and already have the gauge to do it with.

Fuel lines from tank to pump are metal, except inside the engine bay to the pump is rubber. Then out of the pump is metal, up to right near the throttle control, and from there to the carb is rubber. The rubber hose going to the carb is in great shape, not the least bit brittle or worn (I cut about 1/2" off each end to play it safe, and found it to be totally flexible and… rubbery) but I’ll be replacing it with a new hose tomorrow anyway, when I install a new fuel filter, since the existing hose isn’t long enough to get the filter out from under the air cleaner.

I would actually be interested in a clear filter since the tank and fuel lines are a bit of an unknown at this point. Not sure if they were replaced during the restoration that was done 15 years ago. So I’d like to be able to see what the filter is filtering out.

If nobody voices concern over a plastic filter by tomorrow, I’ll probably just pick one up. It’s only like $6. If I buy a new length of hose, I can route it so it’s not touching or too close to anything hot.

You are starting to stack band-aids on top of each other.

Most carb problems are ignition related. Meaning most problems that you think are carb related are not carb problems.

Simplify things first. Put a timing light on the car and see if the timing is between 6 and 12 degrees before TDC with the distributor vacuum line disconnected and plugged. If the timing is jumping around it means that you probably still have the original timing chain and it is now stretched out and sloppy. If the timing is correct, and rock solid, then you need to look at the points. Ate they clean? is there any pitting in the contacts? You can file them flat, but they are cheap to replace. How old is the distributor cap and the plug wire set? If the wires are 15 years old its time to replace them. How about the plugs? Now put a vacuum on the distributor diaphragm. There should be no air leakage at all.

Once you have the ignition spot on, then move to the carb. Disconnect every vacuum line except the distributor. Adjust the carb according tot eh manual. With a stock cam you should be seeing about 18" of vacuum. Then one line at a time, reattach the vacuum lines. IF you have a leak it should start running crappy when you hook up the line with the leak. Fix what ever leaks. You can’t really adjust around a vacuum leak. The engine is designed to have ALL intake air passing through the carb, not bypassing it through a vacuum hose.

I have run Edelbrocks for years and you don’t need a fuel pressure regulator with the stock fuel pump. You may need to change the rods and jets to lean it out. Out of the box they are set up for a 350 Chevy and seem to be a bit too rich.

The best place to add a fuel filter is where the rubber line runs from the inner fender to the inlet on the pump. Use a steel filter. To see if you have problems, after running the filter for a while (25 miles or so minimum), disconnect the input to the filter and let the filter drain out through a coffee filter. If you see orange brown dust, you have rusty tank or fuel lines. Replace them. If you take the top off the carb and see the same stuff in the bottom of the flat bowls, you will need to clean out the carb, and replace the tanks and fuel lines. This stuff is too fine to be stopped by any filter.

Excellent advice as always Bill. I’m going to re-read that multiple times for sure.

Quick info–

Plug wires are roughly 150 miles old. Replaced em the day I bought the car.

We checked the timing when I was at my dad’s buddy’s buddy’s awesome garage with the lift. Timing was solid at 6* with the distributor vac advance disconnected and carb port capped.

I’m getting 18.5 mmhg vacuum at idle, and that’s with everything vacuum-based connected except the headlight system. I disconnected it to have a port to measure vacuum while adjusting idle mix and rpm. Got the idle set great, both screws ended up fairy close to 1.5 turns out from full in (not cranked down hard, don’t worry!) which from what I read is typical. When I reconnected the headlight system the idle rpm dropped a little and got a little less smooth, not horribly but enough that I assume it’s affecting performance/rpm in the name of bells and whistles, so for now I’ve capped that port and left the headlight vac disconnected until I can get a mityvac and try and isolate any issues. Brand new check valve purchased from WCCC and installed a couple weeks back, to replace the shot one that was in there, but the problem persists. I believe the headlight actuators are leaky because I can open and close them with my thumb over the main headlight vac line that was connected to the manifold, so that means they’re leaky in at least one direction (depends on how the headlight switch was set - in this case off) right? Or am I misunderstanding there?

Plugs, I don’t know the age, and I’ve never opened up the distributor, so both could be culprits for sure. I’d like to replace the plugs as a matter of course, just because I don’t know anything about them and it couldn’t hurt. The distributor, it seems like the MSD is pretty popular and eliminates the points concern, so is probably worth doing? Is there a reason not to do both of these, for a car that’s intended to be a driver not any type of show car?

The fuel filter sure isn’t a bandaid, right! The fact that it was run for who knows how long without any fuel filter is of course a bad omen. And for all I know the tank and lines are original and full of flaking shellac and rust and all that. I love the coffee filter idea and look forward to doing it. Well, I don’t look forward to the results I expect, but I’m eager to do the test.

The pressure regulator is a bit of a bandaid, but, with the spec for the pump being outside the range of the spec for the eddy (and my pump being a brand new modern replacement) it’s not a bad idea is it? Or is it?

I have no clue how dirty the carb may be. I’ve got some pics looking down into it if there’s anything that might be an indicator to you of a problem.

Is spray carb cleaner worthwhile? If it’s worth doing… I’ve never done it, is it just, RTCS (read the can, stupid)?

I’ve also never checked the floats, though I’ve read multiple times that it’s something to do, is important, is often wrong even right out of the box, and is relatively simple. Recommended?

I’ve never pulled the top of a carb off before either, so all I know about carb removal so far is “don’t let anything fall in the intake or you’re in for major headache”. I wanna keep getting my hands dirty though, and gradually learn everything there is to learn, so I’m eager to do this kinda stuff. Anything critical to know about pulling the top off the carb to check the bowls? Or just look at the manual and have at it?

And just as a data point for you, if it helps… The idle is smooth at 500-550 once warmed up, aside from the occasional “puff” which I would love to have a better way to describe. And acceleration is right on as far as I’m concerned, no drop outs or weird transitions with either mild or heavy acceleration, no ill-performing that I’ve noticed. It’s just the puffing at idle. If it wasn’t for that, I wouldn’t even be thinking about any of this stuff, I’d be focusing on getting the slop out of the steering like we talked about before.

Thanks again. I’m going to go re-read that post a couple-few more times and make sure I’m digesting it fully.

Oh! And about the tank and line replacement… I know you have suggested it as a standard move to make with any 40 yr old car, and I have fully intended to do it, though a couple people have tried to talk me out of it, saying that replacing the lines is really difficult because of the routing and all that. Are they just being wusses? Does it involve any disassembly of the car beyond removing the connectors that hold the lines in place, removing em, fishing the new ones in place, fastening and connecting it all up? Does tank replacement involve more than just draining the tank, unscrewing and pulling it out, putting the new one in place and bolting it in, connecting the sender and line? This stuff sounds simple enough to me, well within the scope of what I can knock out in a weekend. Am I missing something? Are they wusses? Major disassembly, removing body elements, welding, any of that? I apologize if this is an annoying line of inquiry that comes up too often, and if there’s already a good post or thread or website that covers this stuff, if you could point me at it rather than rewriting something you already wrote, that would rule. I’ll do some searching as time permits, too, but that usually ends up with me finding 500 threads that mention tank replacement and don’t go into any of these details.

Thanks again, Bill.

I have a busy day today so I will have to come back to this later. I wish I was in Chicago, we could knock most of this out in an afternoon. Those guys are just being wusses. None of this stuff is difficult. BTW, and occasional puff is normal on a carburetor equipped car.

Thank you so much Bill! I promise, however much you wish you were in Chicago to help me with this stuff, I wish it double, or triple, or more.

I agree with Bill’s assessment. You have more things to check first…

But to answer the ??? at hand, I run the same carb as you on a 351W and have a 7 lb electric fuel pump mounted back near the tank. I run a serviceable fuel filter into the pump (recommended) and then another filter (metal canister type) just before the carb. I used to run a regulator up near the carb with a gauge and it was set at 5.5 lbs. The car ran great! Once the car got hot, the gauge would drop to “0” but the car would run no different. With the latest rebuild, I decided to try simplifying a few things and decided to try it without the regulator. Guess what? The car still runs no different. So I didn’t bother adding it.

As for the filters, the plastic ones are fine if they’re not touching anything. STAY AWAY FROM THE GLASS ONES!!! I had one come apart and it turned the intake manifold into a bubbling swimming pool of gas. Luckily I was backing into the garage when it happened. My buddy wasn’t so lucky. His came apart on the road and two dry chemical fire extinguishers later, the flames finally went out. The engine was a TOTAL mess and he could NEVER get that carb to run right again even after rebuilding it.

Oh and he had to repaint his hood too. :thumbdown:

Responses are inserted below in bold.

Ok, I’m back to my previous plan then, to replace the tank and lines. You’ve sold me on it. :slight_smile:

The idle is 500-550 in drive. In park it’s closer to 800.

I’ll run the tank down before removing it, but I don’t want to run it too close to empty, do I? Isn’t that the worst and most crud-filled place to grab gas from? I’ve been making a point of never letting it get below the 1/4 full mark on the fuel gauge for this very reason. If I run it down to a little under 1/4 full and then remove the sender apparatus and drain that last 5 or 6 gallons into a pan, is that worth it? Better to not run all that extra crud through the carb and engine? Or is it not a big deal to do it the one time only?

And importantly, with a new tank, how does the filler tube connect to the tank itself? No welding, right? I’m not set up for that, and though I do plan on it long-term, I won’t have money to dump into getting set up for that in the short term, and don’t know that I’d want my first welding to be related to the gas tank either for that matter.

Use the drain plug to drain the tank. It’s on the front passenger side corner of the tank. The filler neck is clamped on with a rubber sleeve in the trunk.

When you want to pour the gas you drained out into the new tank, I line a funnel with a automotive paint strainer to capture any crud you don’t want back in there.

Matter 'O fact, I use a paint strainer to strain used antifreeze when I pour it back in too.

Is a paint strainer better than a coffee filter?

Use a good paint strainer from a automotive paint supplier, not one from your local hardware store, there not as good. You can use a coffee filter if you want, but it will be very very slow.

I don’t drink coffee, but I DO paint. So I use what I have on hand. :slight_smile: … and they fit inside a funnel better.

The coffee filter is good when you are trying to see really fine particles of rust, but it will take much too long to pour any quantity of gas through one.

Paint strainer it is! Between that and the Barkeeper’s Friend (which the guy at the local CarQuest who really seems to know his stuff said is the way to go for removing the spiderweb scratches in my windshield) I’m gonna be taking a couple adventures to new places I haven’t been before. Or currently know who or where they are for that matter. Good times.

Thanks guys!

You drink paint? I heard of sniffing it but…

Yup, I knew it, he’s a paint drinker…What a lush. :crazy:

So, an eventful night tonight in the cold dark garage. Maybe 40 degrees, if that. Brrrrr!

I went ahead and jacked up both sides of the front, third lowest setting on my jack stands, figuring that would keep the fuel from pouring out when I disconnected the line between the fender and the pump, 3/4 full tank and all. Just to play it safe, I had a length of hose with one of those auto-tensioning clips held open with mini vice grips, so if it did start pouring fuel I could quickly throw the hose on, aimed upward, so no fuel would come out.

Totally unnecessary. Jacking up the front end did the trick. Not even a drop.

Got the steel filter in place between the fender and pump.

Didn’t think to buy and bring a coffee filter because I wasn’t expecting to be looking and fuel precipitant until after I put some miles on with a fuel filter in place. But when I disconnected the hose between the main fuel line and the pump, there was of course gas in it. So I went ahead and poured it onto a piece of paper to see what I got.

That didn’t look so great to me. I poured the fuel out in the alley (don’t tell EPA) and let the paper dry. There was indeed some tiny bits of junk left over. Great.

While I was down there I noticed something pretty ugly.

Got a new length of hose installed between the pump and carb.

Adjusted the accelerator springs out to the last position available on the little hole-strip extension I added since the doubled spring at the original span made it pretty brutal to push the accelerator.

Don’t worry, it’s held in place with a lock nut and besides, I’ve already practiced sliding my foot underneath the gas pedal to manually return it to idle position. :slight_smile:

Went ahead and warmed her up with the radiator cap off so I could test the antifreeze strength, since sub-freezing temperatures are pretty much already here. Was not pleased with the appearance of the coolant or it’s level of protection.

So apparently the top order of business now is flushing the coolant ASAP, followed by replacing the fuel tank and lines. And it looks like cleaning the carb is gonna be a nice winter project for me, cause I’ll bet it’s a mess.