Fuel Pressure Gauge: Electrical vs. Mechanical w/isolator

Dave Muller · 09-08-2015, 12:15 PM

I'm a bit confused at this point; I will be mounting a fuel pressure gauge on the dashboard, and I don't want pressurized fuel right in front of my face. But the budget is getting thin at this point in the build.

It looks like an electric gauge would be in the low-to-mid $200 range, whereas the mechanical/isolator combination would be under $200. If price were no object I think I'd prefer the electric, but I'm not even sure about that. Budget considerations do allow for either choice, but price still matters.

Opinions? Experiences?

Tom Goldman · 09-08-2015, 01:06 PM

Isolaters are a pain in the butt and never give you a reliable reading.
I put in the analog electric in my car and a digital in Jeff Jewell's Vette.
Both work flawlessly and mine is dead on accurate with the data recorder.

Tim H · 09-08-2015, 01:19 PM

Quote:

Originally Posted by Dave Muller

I'm a bit confused at this point; I will be mounting a fuel pressure gauge on the dashboard, and I don't want pressurized fuel right in front of my face. But the budget is getting thin at this point in the build.

It looks like an electric gauge would be in the low-to-mid $200 range, whereas the mechanical/isolator combination would be under $200. If price were no object I think I'd prefer the electric, but I'm not even sure about that. Budget considertaion do allow for either choice, but price still matters.

Opinions? Experiences?

I have had a couple different cars both with the Isolator system and have been happy each time. My isolator uses antifreeze to pressurize the gauge that is inside my car.

Rob Petrie E395 · 09-08-2015, 01:47 PM

I have the isolater with antifreeze in 1 car. And a electric in my other car. I prefer the electric. Mainly because when it comes time to work on the car its alot easier to uplug the sensor than it is to take the line going to the isolater off the fuel rail. Due to where the port it goes onto is. Other than that they both seem to work well for me.

Dave Muller · 09-08-2015, 05:41 PM

Quote:

Originally Posted by Tim H

I have had a couple different cars both with the Isolator system and have been happy each time. My isolator uses antifreeze to pressurize the gauge that is inside my car.

What's involved with installing an isolator? Do you have to put the fluid in and bleed the air out? Does the line come sealed with fluid already in it?

Rob Petrie E395 · 09-08-2015, 05:58 PM

The isolater and line are assembled and filled with antifreeze and capped with a steel cap from the factory. The gauge has to be filled and comes with a little bottle with what I would describe as a plastic needle. You set the gauge on its face and fill the insides using the plastic bottle/needle deal. Through the port on the back where the line threads on. Then you run the line into the car. Remove the cap on the line and install it on the gauge.

Dave Muller · 09-08-2015, 07:34 PM

Thanks for the explanation.

Sean Marconette · 09-08-2015, 08:24 PM

Just a question, is the isolator gauge open to atmosphere after it is filled? If it is closed does anyone notice a difference in the gauge reading when it's hot or cold?

The reason I ask these questions is, if the gauge is sealed to atmosphere temperature fluctuations will impact its reading. You may not notice this if it does not start at 0 on the gauge. I used to use a glycerin filled 0-15 PSI gauge for my tire pressure. I always had to open the vent port to zero the gauge each time it was used if the temperature had changed. I finally dumped the glycerin. This is just an example of a fluid in a sealed vessel, unless they are pressure compensated they may not be as accurate as you may think.

At least with an electric sensor and gauge, as long as the span of the sensor and gauge are the same it will give consistent readings.
Something to think about.

Sean

SSGN · 09-09-2015, 11:41 AM

Can't beat the classic looking hood mounted on an older car. Simple , reliable, and looks like a stocker. Just a thought

Kevin

Dave Muller · 09-09-2015, 01:07 PM

Quote:

Originally Posted by SSGN

Can't beat the classic looking hood mounted on an older car. Simple , reliable, and looks like a stocker. Just a thought

Kevin

And I'd love to put it there, but NHRA tech told me no gauges on the outside of the car.

09-08-2015, 12:15 PM	#1
Dave Muller Member Join Date: Apr 2014 Location: Mesa, AZ Posts: 497 Likes: 162 Liked 223 Times in 73 Posts	Fuel Pressure Gauge: Electrical vs. Mechanical w/isolator I'm a bit confused at this point; I will be mounting a fuel pressure gauge on the dashboard, and I don't want pressurized fuel right in front of my face. But the budget is getting thin at this point in the build. It looks like an electric gauge would be in the low-to-mid $200 range, whereas the mechanical/isolator combination would be under $200. If price were no object I think I'd prefer the electric, but I'm not even sure about that. Budget considerations do allow for either choice, but price still matters. Opinions? Experiences? Last edited by Dave Muller; 09-08-2015 at 01:21 PM.

09-08-2015, 01:06 PM	#2
Tom Goldman VIP Member Join Date: Jan 2003 Location: Allentown,PA Posts: 2,474 Likes: 885 Liked 859 Times in 234 Posts	Re: Fuel Pressure Gauge: Electrical vs. Mechanical w/isolato Isolaters are a pain in the butt and never give you a reliable reading. I put in the analog electric in my car and a digital in Jeff Jewell's Vette. Both work flawlessly and mine is dead on accurate with the data recorder. __________________ Tom Goldman 1500 SG , 1506 STK

09-08-2015, 01:47 PM	#4
Rob Petrie E395 VIP Member Join Date: Dec 2007 Location: Woodlawn IL Posts: 1,092 Likes: 162 Liked 216 Times in 77 Posts	Re: Fuel Pressure Gauge: Electrical vs. Mechanical w/isolato I have the isolater with antifreeze in 1 car. And a electric in my other car. I prefer the electric. Mainly because when it comes time to work on the car its alot easier to uplug the sensor than it is to take the line going to the isolater off the fuel rail. Due to where the port it goes onto is. Other than that they both seem to work well for me.

09-08-2015, 05:58 PM	#6
Rob Petrie E395 VIP Member Join Date: Dec 2007 Location: Woodlawn IL Posts: 1,092 Likes: 162 Liked 216 Times in 77 Posts	Re: Fuel Pressure Gauge: Electrical vs. Mechanical w/isolato The isolater and line are assembled and filled with antifreeze and capped with a steel cap from the factory. The gauge has to be filled and comes with a little bottle with what I would describe as a plastic needle. You set the gauge on its face and fill the insides using the plastic bottle/needle deal. Through the port on the back where the line threads on. Then you run the line into the car. Remove the cap on the line and install it on the gauge. Last edited by Rob Petrie E395; 09-08-2015 at 06:01 PM.

09-08-2015, 07:34 PM	#7
Dave Muller Member Join Date: Apr 2014 Location: Mesa, AZ Posts: 497 Likes: 162 Liked 223 Times in 73 Posts	Re: Fuel Pressure Gauge: Electrical vs. Mechanical w/isolato Thanks for the explanation.

09-08-2015, 08:24 PM	#8
Sean Marconette Senior Member Join Date: Mar 2006 Posts: 977 Likes: 792 Liked 275 Times in 76 Posts	Re: Fuel Pressure Gauge: Electrical vs. Mechanical w/isolato Just a question, is the isolator gauge open to atmosphere after it is filled? If it is closed does anyone notice a difference in the gauge reading when it's hot or cold? The reason I ask these questions is, if the gauge is sealed to atmosphere temperature fluctuations will impact its reading. You may not notice this if it does not start at 0 on the gauge. I used to use a glycerin filled 0-15 PSI gauge for my tire pressure. I always had to open the vent port to zero the gauge each time it was used if the temperature had changed. I finally dumped the glycerin. This is just an example of a fluid in a sealed vessel, unless they are pressure compensated they may not be as accurate as you may think. At least with an electric sensor and gauge, as long as the span of the sensor and gauge are the same it will give consistent readings. Something to think about. Sean __________________ Sean Marconette 84 Mustang 5060 SS/N

09-09-2015, 11:41 AM	#9
SSGN Senior Member Join Date: Feb 2006 Posts: 644 Likes: 131 Liked 140 Times in 51 Posts	Re: Fuel Pressure Gauge: Electrical vs. Mechanical w/isolato Can't beat the classic looking hood mounted on an older car. Simple , reliable, and looks like a stocker. Just a thought Kevin __________________ The more people I meet the more I like my dog Kevin