Why do I have high fuel pressure...

[DanEC]

You have apparently been having this problem off and on for awhile.

very high fuel pressure


Did you manage to solve it back then? I think I would question how accurate the gage is but obviously you are having some problems so it's not all in the gage.

[patrickt]

Once you get her home, whether you limp her home under her own power or use a flatbed, I'd like to see you just Tee in a fuel pressure gauge right before the carb. Chances are you have AN fittings there, with a nice fat braided steel line coming from the fuel pump, so Tee'ing in a gauge is a quick and simple process. Russell, Earl's they all make little AN "Tee" fittings that have a hole for the NPT fuel pressure gauge to go in. Ten minute job at most and I'd really like to have the luxury of knowing what the fuel pressure is without relying on your existing gauge. You can always remove it when we're done.

[steve meltzer]

OK, here's the plan. I'm gonna take one of the big paper clip like deals that will hold 150 pages of BS and clamp that hose (I got it off with my little "Leatherman" like too). My wife can follow me the 6 miles home and, as you said, I can get 'er home and go from there.

WOW, Dan Ec....I had totally forgotten about the post back in '06....thanx so much. I did wrap the fuel rail/log with some foam rubber insulation and I think that helped. Hadn't been an issue since. I don't drive the car too often when it's really hot, as if I get stuck in traffic, the car gets hot (100-105C) and it makes me too nervous to be much fun. Today, it's a gorgeous 60°. thanx again. s







More later. thanx again. s

[jhv48]

Correct me if you've already tried this, but why don't you bypass the mechanical pump altogether and just run off of the electric pump? Two pumps, twice the potential problems.

[steve meltzer]

Well, despite my best intentions, the neither the clip nor a surgical clamp from the office worked to obstruct the hose, so, I'll go back to the office on Sunday with a proper hose clamp, block the errant hose and drive her home for the repair. More later.

JHV48, I've not tried anything in the past. The car is now, as it has always been. I understand your point about twice as much potential trouble, but...if the e-pump fails (and it did about 5 years ago), i could make it home on the mechanical pump. Thoughts? thanx. s

[patrickt]

If that Carter mechanical pump that I gave the link to fails in the next ten years I'll have RodKnock dance naked on the hood of his Kirkham with a rose clenched between his teeth. Yes, I'm that sure it won't fail.

[steve meltzer]

WOW! Thanx Patrick for the tips and great info. I ordered the Carter FP and i do have the clutch head driver attachments, tho' having two 'Vettes with Holleys, i may just order the correct tool. More later. I can't get the car today and it looks like rain here in Houston tomorrow, so we'll just have to see when i can get the car. thanx again. s

[patrickt]

I think I could even lead my brother, who barely knows a screwdriver from a hammer, through a rebuild of a 4160. And over the last 40 years I've made every mistake humanly possible to make -- so I can see them coming and tell you how to avoid them. The first step, though, is to temporarily plumb a new pressure gauge right in front of the carburetor. The second step will be to conquer your fuel pressure issue. The last step will be to rebuild the carb with that kit. It's a better than fair chance that the 9psi that you were seeing resulted in the secondary flooding out by eating the needle/seat valve for lunch. So there's no sense in even touching the carb until we have a nice, clean, even 6psi feeding her.

[steve meltzer]

OK, home again. Gotta way and, with a proper automotive hose clamp, clamped off the aorta, oops, i mean the secondary feed line. With out the e-pump on, and after about 10 minutes of slow speed running the gauge again read 9 PSI! DX: bad mechanical pump, and it's on its way out! Opening the gas cap didn't change a thing.

When you seal the bowls to the body, do you put anything on the gaskets, like Permatex 518? thanx s

[patrickt]

Originally Posted by steve meltzer

When you seal the bowls to the body, do you put anything on the gaskets, like Permatex 518? thanx s

No, absolutely not. We will use the BLUE gaskets that come in the kit and spray them lightly with silicone spray lubricant. Cleaning off the old gaskets is imperative. I like to use wooden toothpicks to clean off the old gasket material. Cleaning the needle/seat nut is usually the most time consuming. Never use anything that can scratch the metal.

[steve meltzer]

got thanx. s

[steve meltzer]

Whata fight gettin' that fuel pump out without removing everything within 2'. So, now I wonder if I should just block the block and skip the mechanical pump altogether, or am i just being lazy? Pros and Cons? Your take? thanx. steve

[patrickt]

Originally Posted by steve meltzer

Whata fight gettin' that fuel pump out without removing everything within 2'. So, now I wonder if I should just block the block and skip the mechanical pump altogether, or am i just being lazy? Pros and Cons? Your take? thanx. steve

Personally, I am partial to mechanical pumps. And the new one will go in easier than the old one came out. Do you have a UV flashlight? The reason I ask is that, because you had the secondary flood, it will make being sure you've sealed everything off a little tougher. Generally, after you've done your carb work and put everything back together, you tuck paper towels under the bowl, crank it up to fill the bowls, and if you don't see obvious gushing leaks, you pull the paper towels out to see if you have any dribbles, or seeping leaks and then you put them back in and let them sit there overnight. But the fact that you've had gas everywhere, you're going to get witness marks on that paper towel that might be real, or might be leftover gas. What I like to do after I've had my carb apart, and I think it's done, is put an eyedropper full of UV dye down the vent of the bowl I was working on. You would be surprised at how many times doing that has tipped me off to a problem, or confirmed the fact that the gas stains on the towel were not from the bowl because there was no dye in it. It really takes the guesswork out of leak detection. Here's the stuff I use and it's fantastic. I use an eyedropper from an old Rogaine bottle, which puts the perfect amount in to a Holley bowl.



Buy it off Amazon here: [ame]https://www.amazon.com/gp/product/B008B57Q5I/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1[/ame]

[steve meltzer]

OK, new Carter fuel pump installed and I drove the car, secondaries blocked. Fuel pressure a constant 6.25 +/-0.25 PSI. Whether the e-pump was on or not, the car held at same 6+ PSI. I assume the sl. bit above 6 is the gauge or, within spec. Install was a bit of a fight, as there's not much room on a Kirkham, but it's done and dry. Carb on the bench for new gaskets and needle/seat this week. More later. thanx again. s

[patrickt]

Excellent. That pressure is right where you want it. Now, you know, the odds are very, very high that the only thing you need to do now is replace the needle and seat valves ,because of the previously high pressure. On your 4160, you can do that without removing the carb from the manifold or, for that matter, even pulling the bowls. It's literally a five minute job and then you set your floats and mixture screws and you're done -- just check for leaks. I think that's what I would do.

[steve meltzer]

Glad to hear i'm on the right track...but, the carb is off so I might as well do the gaskets as well as the needle/seat. Good experience in any event. thanx again. steve

[steve meltzer]

I actually have some, and an eye dropper as well, so i'll do that. The old pump was a Carter 0-3000. Great help! Thanx so much. steve

[patrickt]

That fuel pump should just slip right on your block in a jiffy. And the rebuild of the secondary side of the carb is a breeze. Have you ordered that rebuild kit?

[steve meltzer]

The M6905 (this is correct for a 427, right?) pump came in the mail today, and I hope to put it in this week. I did order the rebuild kit, so depending on stabbing the pump, plus other projects, I might get to that this weekend, not sure at this juncture. thanx again. s

[patrickt]

Originally Posted by steve meltzer

The M6905 (this is correct for a 427, right?)

Yep, fits everything from a 352 to a 428 and all numbers in between, so long as they're an FE.