Fuel Pressure Gauge

Has anyone installed a fuel pressure gauge under the hood of their carb car? I am thinking of putting one in to monitor the pressure but am not sure where to put it . Before carbs or after?

Mike

 

If you install a pressure regulator it goes between fuel pump and carbs, so a gauge would have tha same position I guess.

Pero

 

If you install a pressure regulator it goes between fuel pump and carbs, so a gauge would have tha same position I guess.

Pero

 

I was thinking of one, but I would mount it where the clock is in the console. I want to know when the pressure is dropping while driving.

 

Im clueless.

Who cares and why? Seriously.


Once you clean these filthy cars up (even hanger Queens are FILTHY, perhaps worse), that needle should not waiver for 20 years.

 

Amen! Why fix a problem that isn't there??

 

Shirley, you jest...and don't call me Shirley, either. We do care, but only for diagnostic purposes. And on a carbed car, we actually care more about delivered volume than pressure. So....do we really care? No, unless we have a specific driveability concern. I suspect that this explanation is far beyond the scope of the OP question.

And would I really want a fuel gauge subject to those under hood temps? Probably not, although some NASCAR company likely makes an engine compartment safe fuel gauge.

 

Ok, Surely. Got Ya.

Now I understand.



But for volume/time checking (FI Car), I just used clear plastic Dixie Cups and a chem lab graduated beaker.

Worked just fine.

 

The process is essentially the same for a carb car. (See 365bb in profile). I just use a stainless steel measuring cup ( one litre) size, instead of a Dixie cup. As you said, it works just fine.

 

As noted above, if I have a fuel pressure gauge, I want it in the car.
However a Fuel pressure gauge is pretty useless, it's a novelty kinda like the clock, amp meter, power windows and some think the radio.

I have several supercharged cars and fuel pressure in those is important. But I have learned old cars have pumps that fail, fuel tanks that have collected debris that clogs filters, so a gauge lets you know there is something going on in the fuel system and it's to think about how you’re getting home.

 

Doug,

Now I understand.

But I maintain if you clean them up (and I am sure you and most here are or are in the process) then this should not need to be an issue to deal with.

Seriously, Best of Luck in whatever direction you go.

 

my fuel gauge and pressure regulator - for running 45PSI . this is for the fuel injectors that i used with the TWM setup. hope this helps.
note, the gauge was never affected by under hood temps -fyi.
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The reason I posted was because I think my last carb is not getting enough fuel as it is running lean. If there is pressure in the line before the first carb and minimal at the last, that could be the problem. There is some type of check valve on the return to the right tank and if that is not allowing sufficient pressure to build to fill the last carbs bowl that could be my problem. Could be a restriction in the fuel hose (collapsed? or debris?) That is why I asked where to place it. I am sure my idle jets are lean but this could also be the problem.

Mike

 

or you may have an intake manifold gasket leak, i had multiple leaks in my gasket - what a mess. once i cleaned up everything and put on new gaskets, problem solved (for me anyway).

 

This check valve is not the problem. The valve is not there to build up pressure. If your last carb is running lean, I'd guess a leaky gasket as well. If you had a blockage in the fuel line between the first and last carb, you'd probably see other problems first like fuel overflowing from the first carb and/or flooding.

 

this is what happens when coolant types get mixed (the green and the orange). i had major pitting on the manifolds that had to be re-welded and resurfaced. lots of air was getting in.
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The inlet pressure to each carb shouldn't be all that different as the tubing from the (stock) regulator output to the flow restrictor (built into the 7/8 carb inlet fitting -- it's the barb where the small return line exits to go to the RH fuel tank) should form a common manifold all at the same fuel pressure.

(If yours is a US version '79 308) This can only affect cyl #8 (and not cyl #7), but the large vacuum fitting on the cyl #8 intake manifold runner (that goes to the airblox flap system) should be connected to a completely "closed" system (i.e., no continuous airflow enters that port). If that fitting is "open" in some way (like wrongly being used for the charcoal canister), that would lean out #8 so that it could probably never work right at idle. Are your airbox flap system and charcoal canister system modified/molested in any way?

 

I would be concerned about running fuel up to and into the passenger compartment. One way to avoid the potential of a fuel leak in the car is to utilize an electric gauge with a sender, much like our oil pressure gauge, rather than a hose full of fuel to a mechanical gauge.

To paraphrase Carroll Smith, Nothing good has ever been said about a fuel leak in the cockpit.

Suddenly, a big halon extinguisher sounds very comforting...

chris

 

There is a diaphram that goes inline to keep fuel out of the passenger compartment.

 

Learn something new every day - thanks.