Fuel Pressure Drop

[earlbrown]

liquid filled gauges are inherently screwy based on temperature.

 When the front of the face is sealed it can't be referenced to atmosphere and the pressure in the sealed compartment can cause the gauge to read low based on thermal expansion.

[bescurred]

The one I sent him was not liquid filled and it was not a POS.

I have seen more than one liquid filled gauge that was no good.

Gotta part # I was saying mine is a piece

[PacecarTA]

i run a three foot braided -4 hose and use autometer liquid filled fuel gauges (2 5/8) mounted in a cup mount like you would mount on the hood , but i ziptie them to the cruise bracket  by the air cleaner , if need arises the gauge could be swung up to the windshield
 
no way i would ever run one of those rail mounted gauges for something as important as fuel pressure is to these motors
and a pressure sensor logged on the PL means nothing if the calibration isnt checked or was baselined to a bad gauge  .. for clibrating the sensor you need a good gauge that hasnt been shook to shit , ive seen those railmount POS gauges  off more than 20psi
for calibrating i use a  compressor regulator with a calibrated gauge that uses  shop air  , i also use that regulator setup to verify boost gauges (fyi vdo 30psi 2 1/16 boost gauge that is probably the most common used gauge  are by far the most inaccurate boost gauges ive ever tested , how about being off  7psi at 20psi!!!)

[Steve Wood]

It was an Ashcroft 3" 2% accuracy unit. Last I looked, it cost somewhere over a $100.  Everything Paul said is right. Rail mounted gauges are useless

[Scoobum]

Steve the latest update I got from him is the fuel pressure climbed to 46 line on. The fuel pressure gauge is an electric in car, I'm dropping him off a spare AFPR to his mechanic today to install. I'll report back.

[Steve Wood]

That explains it

[daveismissing]

If you have a source to check the calibration Ebay has lots of used industrial grade gauges.Otherwi se I posted a Mcmaster Carr number for something decent a while back.

I suspect if you put enough rubber hose on a non dampened gauge it would become quite usable- just a guess tho.

[earlbrown]

Definatly want to buy a good used gauge and verify the calibration.   Large faced quality industrial gauges cost a WAD (giggity) when bought new.

When I started pricing 4" temp gauges for my still I almost passed out!

[Forzfed]

It was an Ashcroft 3" 2% accuracy unit. Last I looked, it cost somewhere over a $100.  Everything Paul said is right. Rail mounted gauges are useless

I take it that is 2% of full scale and not reading?  I've seen real cheapo gauges that had accuracy of reading, needless to say they were POS.

[Steve Wood]

actually, I was wrong, it is an 0.5% accuracy gauge +/- 0.5 of the range

[SuperSix]

How bad could this gauge be?

http://www.northerntool.com/shop/tools/product_357793_357793

[Forzfed]

Gauges are the most accurate at the 50% reading.  Notice this one lists 2-1-2 for accuracy?  Only way to say how good it is for sure is to test it with some good calibration equipment.  Most the places I've worked if we are reading 100psi pressure on a process, the gauge will have a 0 to 200psi scale.

[SuperSix]

Gauges are the most accurate at the 50% reading.  Notice this one lists 2-1-2 for accuracy?  Only way to say how good it is for sure is to test it with some good calibration equipment.  Most the places I've worked if we are reading 100psi pressure on a process, the gauge will have a 0 to 200psi scale.

Interesting..

So a ~140psi gauge would be perfect, not sure if that scale is available.

I noticed it says it has a temperature compensating window..

I saw a whole shelf unit of various pressure gauges last time I was there. I may give one of these a shot - not rail mounted though.

[earlbrown]

How bad could this gauge be?

http://www.northerntool.com/shop/tools/product_357793_357793

It's liquid filled so it'll be affected by temperature swings.

[bescurred]

How bad could this gauge be?

http://www.northerntool.com/shop/tools/product_357793_357793

It's liquid filled so it'll be affected by temperature swings.

The one I just got isn't liquid filled but the reading is bouncing around...that's not normal right?  My liquid one I pulled of wasn't doing that.