Thread: fuel pressure gauge

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hi to all

i would like to know. will i need to run a fuel pressure gauge. i have a 70 400sbc stock with a 600 cc carb and mach fuel pump.

thanks for any help

Probably not - if your pump is stock mechanical unit it should put out about 4-5psi. The gauge will only tell you what your pump is putting out - it will not regulate.

Gotta disagree! One of the most common problems that people have with the Edelbrock and AFB Carbs is excess fuel pressure,both Tech Inspector and myself have brought this point up many times over on other sites.The first thing people will is "I only have a stock fuel pump" it is not uncommon for stock pumps to push 7-8 psi.If you run one of these carbs, GET A REGULATOR! and set it at 4.5-5 psi no more.

In the past 45 or so years of working & racing cars, I have never had a need to have one. I have checked my fuel pressure, but never needed or mounted one under the hood. Mostly on a stock type motor. Or anyone I know.

Pat

Probably not a requirement to have a fuel pressure gauge, but they are nice to have as a tuning tool later on.... Seen far too many new pumps and other parts built in the last 10 years that do not perform as advertised....quality control is pretty much dead, I think.....

The "concept" of having a fuel pressure gauge permenently mounted is a good one.

However, in my experience is that the quality of the small liquid filled fuel gauges is so poor that they are a waste of time and do not read accurately when they get warm in the engine compartment. If your dead set on using one, I would open the plug in the back of the case and drain out the gauge and leave the back open to the atmosphere pressure (not sealed).

Just use a real pressure/vacuum test gauge, set your regulator to the desired pressure, and forget it.

A fuel pressure guage is just as necessary as an oil pressure guage----you can get along without either one, but I want to know what is happening with my engine----I have seen many more tuning problems that knowing that the fuel pressure was would of been more beneficial than knowing what the oil pressure was

And I didn't read about it!!!!!

On cars that I consider a fuel pressure gauge as a "got to have it" item, I spend the extra bucks and get the Autometer gauge with the fuel pressure isolater and have the gauge in the car where I can see it.... Keeps the gauge visible without the risk of having fuel inside the car.....

Wow – I never thought this thread would end up in a flaming contest. My initial answer assumed that we were discussing a stock SB400 and a 600cfm carburetor. I also made the assumption that the engine was utilizing a stock (original) mechanical fuel pump (GM 6470779 or similar) that is designed internally to limit pressure to not greater than 7psi. Though a filter, this application typically ends up with about 5-6psi max at the carburetor inlet. Remember that these GM mechanical pumps have done a pretty good job as designed for over fifty years in – on many a Carter carb. My comment about the gauge was intend to state that a gauge doesn’t regulate anything – it simply indicates what the pressure is at the point of insertion (of the gauge).

That said, if you want a fuel pressure gauge – install one. If you’re experiencing symptoms of too much fuel pressure, the gauge can be useful in diagnosing and if the pressure is too high, a regulator can be installed. Race applications obviously have some different overall requirements - but we're discussing stock application here with the exception of the 600cfm aftermarket carb.

It would appear that we all have opinions and that’s what this forum is all about. To exchange a few good natured “barbs” is expected, but to engage in the level of character assassination seen here is, in my opinion, really counter productive and leaves me a bit confused as to why it’s necessary.

I’ve too read a lot of books but also have had my share of grease under my finger nails. I’ve built a bunch of motors – several really sweet ones – but broke a few as well and have been frustrated to tears when I can not find out why the small block that ran well before will not idle worth a darn after I’ve installed a new manifold and carburetor only to read a hint on this form that not only addresses the issue – but gives me what I need to fix the problem and once again helps me realize how much I just plain enjoy wrenchin’..

I have never met anyone on this forum face-to-face, but would like to think I could sit and have a coffee or a beer with any of you and enjoy putting a face to someone who, in all likelihood, has shared information that has been of value to me (and others, I’m sure) as I have participated on this site.

Can we keep this civil? Thanks for lettin’ me vent a bit!

Regards All,
Glenn

2fast4u turned out to be Tango who just wanted to come here and stir the pot for reasons I cannot fathom, all offending posts have been removed, Tango's alternate account has been deleted. Let's try not to degenerate any other threads into off topic attacks.


Bill S.