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Discussion Starter #1
What should the fuel pressure be on the 96 F350?

Also, I have a boost gauge, and pyro gauge, what is the third gauge i should add to my pillar?
 

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i believe normal fuel pressure is around 50-60 psi, and some guys with the shimmed FPR are around 65-70. but i'm sure someone else will chime in too.

as for the third gauge..if its an auto, get a trans temp. if its a hand shaker then you could do hpop pressure. a lot of guys are running a scan gauge but they are a little pricey.
 

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I get 30-40 psi at idle not sure if thats low or not. I would get a trans temp guage if you have a auto.
 

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Discussion Starter #4
I have a manual trans, so im not as concerned with trans temp. I'm slightly concerned about my fuel pressure being a little low, when I changed my fuel filter, I tried to prime the system, and when I turned the key it didn't push any fuel through the lines, I had to start the motor to get fuel to start pumping. It runs, and idles well however its pretty sluggish until I get to about 2000 RPM. I have an intake, 3" down pipe, and a 3 stage chip. It correct me if i'm wrong, but it shouldn't be sluggish. The only thing I can think of is fuel pump or injectors.

That was a long way of explaining why I was thinking of getting the fuel pressure gauge, however maybe yall can shed some light on whats going on with my truck or if that is just normal.

The other couple of gauges I was looking into are Air/Fuel ratio, Oil Pressure, or Air Pressure. Does anyone think this would be a worth-while purchase, or am I wasting my time and money?

I am getting a pyro, and boost, but they have a boost/vacuum gauge. Would that be better or just a boost gauge?

This is the link to the gauges I am looking at.
Tinted 7 Color Gauge Series

That just made this post a whole lot more complicated, but thank you for all the info provided!
 

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Air/fuel ratio is for gasoline engines. They would do no good for diesels.

Only a boost gauge is useful. There is no manifold to read vacuum from. However, there is no harm in having one which reads both.

The OBS trucks have a mechanical fuel pump, so there would be no fuel pressure unless the engine is running, or at least turning over while starting.

The only air pressure gauges that might be helpful are those which fit on the tires. I have a set from PressurePro for monitoring the truck and trailer tires while on the road.

There could be lots of reasons for a sluggish condition.
 

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Discussion Starter #6
Thanks that helps a lot.....clearly I have a lot to learn about the differences between Gas and Diesel motors!

More rookie questions!
What does OBS, PSD stand for?
 

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for a third gauge you could get a fuel pressure gauge, just make sure it's the electric kind or you will have to run a fuel line into the truck (bad idea). My truck idles just shy of 50PSI
 

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Discussion Starter #9
Could someone please explain the "mechanical fuel pump". How does that work?
 

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I vote hpop gauge, that's what I have
 

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The pump is called mechanical because it utilizes a mechanical connection to the engine. This connection is basically a pushrod following a cam in the engine. Thus, it's called mechanical, as compared with an electric fuel pump which is actuated via an electric motor.

I also would recommend an electric gauge, and also use a needle valve to tamper the pulsations of the mechanical fuel pump. Without such a valve, the pump can destroy the sender and the gauge and cause a lot of needle fluctuation that makes it hard to read. I like the needle valve idea, but a specially designed "snubber" installed before the sending unit can also work if it is a good one.
 

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To elaborate, the mechanical pump is a 2 stage design.
Fuel is drawn from the tank to the engine by the diaphragm stage and pressurizes the fuel to 4-6 psi while pushing it into the filter housing.

Filtered fuel is then directed to the piston stage of the pump, where its pressure is increased to between 40-70 psi.
 

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Discussion Starter #13
So the first stage is very similar to the fuel pump for the carbs on a jet ski?
 

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Not sure about a jet ski, but similar to the mechanical fuel pump on older carbureted vehicles.
 
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