Electric pressure gauge.

[BSMiller]

Can an electric oil pressure gauge be used to measure fuel pressure?

Both read in lbs/sq. inch. The gauge would not know the difference, but what about the transducer?

Bruce

 

[BushWakr - RIP]

I'd like to see the replies on this one too..... One thing that may be a snag is the pressure rise/drop fequency causing the gauge to self destruct or be un-readable... ... ... ?????? guys...

Also when a "proper" fuel pressure gauge is intalled an isolater is used to not only ' buffer' the signal but prevent fuel leakage into the cab... (not an issue with an electric guage)



pb...

 

[Mundgyver]

Hydraulic pressure is hydraulic pressure. It should work just fine. The only difference between the oil and the fuel is the viscosity. The electric sending unit designed to handle oil should work just fine for fuel as they use either a diaphram or boron tube design. As with any sending unit though, what is the calibration range (pressure rang). Usually when you buy an electrical set up for oil or fuel, the gage is calibrated to the sending unit and they are sold as a set. Mixing units will affect the calibrated standard reading through differences in resistance and windings of the units. That is why you usuallybuy them as a set.

 

[BSMiller]

When I was thinking about using an electric oil pressure sender ( transducer ) for fuel, two things came to mind. Are the drilled hole sizes the same on both senders and what is the viscosity of oil hot and cold as compared to diesel fuel?

Having a 1990 with a stock lift pump, will it cause a spike problem if the sender hole is larger? Should a snubber be installed up stream of the sender?

Also assuming the sender is nothing but a changing resistance signal to the gauge, why cant a resistor be added in parallel or series to the gauge to change readings by a factor of 10?

Bruce

 

[Mundgyver]

A smaller hole will or should = less surging (spiking) of the needle because you are slowing down the response time of the sending unit. With regard to the resistor, if you put it in parallel, total circuit resistance will drop. If you put it in series, total circuit resistance will rise. In a parallel circuit, voltage across the load will remain the same and current will vary through each leg. In a series circuit the current through the circuit will remain the same and you will see the voltage vary as you go from one side of the circuit through the components to the other side. Give it a try, worst thing that will happen is that it does not work and you wind up buying a complete set up.

 

[Greenleaf]

I use both for both.



Sometimes I will have to introduce a pinch valve when testing some piston lift pumps with a mech. gauge. Never had a problem with the electrical gauges.



GL

 

[BSMiller]

I have read threads where someone would say they heard about problems with electric pressure gauges, but have not read a thread where the person writing had the problem.

What is the real truth?

 

[Greenleaf]

The electric is nearly fool proof if you can follow the directions to wire it correctly. Correctly.



The mechanical have been plauged with problems in terms of the snubber failing. I have never had to use a glycol snubber, mind you. I only read about them in the second gen forum 24 valve I believe it is.



I did speak with Mark @ PDR recently and he told me that he has used one for years with the glycol snubber and has no problems. I guss you have to believe half of what your told and half of what you read.

 

[glhs]

I too would like to install one. Is Genos garage the best setup or do you guys have another in mind?

I have the Genos garage banjo bolts already installed so I cold check the pressure at the pre-drilled holes before and after the fuel filter.

Kurt

 

[bgilbert]

My 30psi Westach electric FP gauge has lasted much longer than the 3 mechanical gauges I had combined. Used via pay it forward at that too.

 

[BSMiller]

What is the fuel pressure reading on the 1st gen standard lift pump at idle, 1000 to 2000 rpm, and wot prior to and just after a clean filter?

 

[bgilbert]

What is the fuel pressure reading on the 1st gen standard lift pump at idle, 1000 to 2000 rpm, and wot prior to and just after a clean filter?

Stock lift pump spec is 3-5psi idle. Under stock fuel settings, with a healthy lift pump and clean fuel filter at 1000-2000+ should remain the same. 3psi is the minimum spec at wot. Aftermarket injectors and pump tweaks, you'll see zero psi at wot.

 

[glhs]

bgilbert;

Your running a piston style lift pump aren't you?

What are your readings?

Kurt

 

[BSMiller]

Bill Gilbert

Do you use your pressure readings after the filter to determine when to change it?

 

[Mundgyver]

The best indicator for changing a fuel filter is to put a pressure gage before and after the filter. This allows you to see both sides and observe the pressure differential develop as the filter becomes clogged.

 

[bgilbert]

bgilbert;

Your running a piston style lift pump aren't you?

What are your readings?

Kurt

Yes, I see anywhere from 14-18psi idle, cruise, and 11psi wot.

Bill Gilbert

Do you use your pressure readings after the filter to determine when to change it?

I do have it reading after the filter. But I don't use pressure readings to determine when to change the filter. They are cheap enough to change regularly. I change my oil and fuel filter twice a year/every 6 months. I may only drive 8k miles a year. Might be overkill, but I don't have fuel supply issues.