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No Reading from Fuel Pressure Test

891 views 20 replies 6 participants last post by  lederhosen  
#1 ·
Hey Guys.

Just did a Key On/Off Pressure Test with this gauge from Autozone, and I got no reading. I tried two different gauges, so I'm thinking something I'm not doing right.

I did not start the car as according to this guide, the Key On/Off method is what is suggested.
Fuel Pump Test

Black hose is going to the Schrader Valve which is on the rail between injector 3 and 4. My confusion is the clear tubing? I've watched several vids on Youtube and none of them have this T fitting with the tube coming out of it. Their gauges only have the Black Hose.

Any suggestions where this Clear tubing is supposed to connect to? I pulled off the top hose from the Pressure Regulator and tried it there, and still nothing. Regulator also has a bottom hose, but didn't try that one.

Reasons for the test, is I am getting some hesitation when I press the gas upon shifting into gears 2 and 3. More severely though in gear two. Very slightly in 1st gear. However, these symptoms are not happening all the time so it's tricky to give more detail.

No other symptoms that I have noticed. My idle is perfect at 850, no problems starting, no fuel smell, can hear the pump when turing key on, passed emissions so don't think I have a vacuum leak and check all vacuums lines that I could, alternator passed, new ignition control module, and new coil. No frayed plug wires. However, I haven't check the plugs yet.

Appreciate any suggestions.

87 2.3l Manual

 
#2 ·
never seen one with the hoses. If you don't have fuel in those hoses it probably isn't going to measure the pressure. The ones I always saw/used just went right on the rail. try opening the T enough to see some fluid and see if it reads.

This is assuming you checked the inertia switch in the back, fuses up front and you can hear the pump priming.
 
#3 ·
I believe the clear hose it to drain the fuel at the gauge after you take a reading. Put the clear hose in a container, conduct your test and then push the pressure release button on the brass T. This will release the pressurized fuel through the clear hose and into your container.
 
#4 ·
Appreciate you guys stepping in.

Drove it today about 40 miles through town, and got a very minor hesitation once on acceleration in second and third gear.

I tried another gauge from Oreilley, and still no reading with the Key On, and after Starting. Pretty sure I've got it hooked up correctly as I followed these instructions. I just added the Gauge to that adapter.


 
#5 ·
I'm wondering if the shrader valve is working inside of the threaded port on the fuel rail. You're obviously getting fuel to the cylinders.

I'd attach the gauge again and run the plastic tube to a container.

Have someone start the car and then you'd push the pressure relief button briefly.
Is fuel flowing through the gauge and into the container now?
 
#8 ·
Does the hose have the depressor feature on the end that pushes down the plunger on the Schrader? Without that feature, you will never get pressure in the line.
 
#14 ·
The valve works exactly like the valves on your tires. To put air into the tire, your device presses the plunger down and that opens the valve.

So just like when you were a kid letting the air out of some punk's bicycle tire, take a small screwdriver and depress the center pin. I typically put a rag on the end when i do this. Some fuel should spray out. Be careful doing this as there is risk of fire, so obviously do it in a well-ventilated space, and the engine is cold.

The fuel pressure gauge works the same way. The unit needs to depress the pin for fuel to flow into the gauge and pressurize it. SO there is a feature on the end meant to depress the center pin. Make sure it's there and able to depress it
 
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#16 ·
The valve works exactly like the valves on your tires. To put air into the tire, your device presses the plunger down and that opens the valve.

So just like when you were a kid letting the air out of some punk's bicycle tire, take a small screwdriver and depress the center pin. I typically put a rag on the end when i do this. Some fuel should spray out. Be careful doing this as there is risk of fire, so obviously do it in a well-ventilated space, and the engine is cold.

The fuel pressure gauge works the same way. The unit needs to depress the pin for fuel to flow into the gauge and pressurize it. SO there is a feature on the end meant to depress the center pin. Make sure it's there and able to depress it
Great minds think alike.
 
#19 ·
Yup. Lets see a pic of the Schrader valve too while we are at it.