How to test pressure from fuel pump
 

I can not find a schrader valve to hook a test gauge too. Any one know how or where to test the pressure of the pump.

Forgot to say its a 2001

1. Relieve fuel system pressure. Take the back seat cushion out and remove the access panel underneath to disconnect the connector for the fuel pump assembly module. Start the Hyundai Sonata and let the engine run until it stalls from lack of gasoline. Turn the ignition off and disconnect the negative battery cable.
2. Disconnect the fuel pressure sensor vacuum hose. Check for fuel in the line. If there is fuel present in the line, the fuel delivery problem is likely caused by a faulty fuel pump pressure regulator. If there is no fuel in the line, reattach the vacuum hose and continue with the fuel delivery diagnostic.
3. Twist off the fuel pressure test port cap and secure a pressure gauge to the fuel pressure valve. Reconnect the negative battery cable and start the engine. Disconnect the vacuum hose again and check the gauge. It needs to read between 38 and 50 pounds per square inch. High pressures indicate that the pressure regulator is malfunctioning. Low pressures indicate that the fuel filter is clogged or that the fuel pump needs to be replaced.

I saw this on ehow.. And I used this guide when I checked the fuel pressure of my car.

there is no test port. There is only 2 lines. One pressure and the other return.

anyone figured how to do this? I confirm there are 2 lines in my 2001 Sonata 4cycl. One has 2 bolts and the other is a rubber hose with a ring. I suspect the hose with the bolts is the fuel line and the rubber hose is the return? Can anyone confirm on that? Thanks.

You need the adapter from the Hyundai fuel pressure test kit.

Remove the pressure line from the rail, then install test port adapter in between rail and fuel supply line... then install fuel pressure gauge...

I'll take pic of it later today..

You can check pressure from the hose that has the clamp on it. DO NOT remove the one with the bolts holding it on. Unless you got the right adapter, which I didnt. that hose that goes to the intake is a vacuum source for the pressure regulator. I used the autozone fuel gauge rental deal. Take the clamp hose loose and put a 1 or so foot piece of hose on, then use the T fitting and attach the gauge. then attach the hose you removed to the other side of the T fitting. That hose is the return fuel line to the tank. Now turn key to prime the pump and see what pressure. Then crank and see the pressure. Then rev the car up to about 4k and see the pressure. It should not drop.

I used a hand vacuum pump(autozone rental) and pulled about 12 pounds on the regulator to simulate idle then release it and simulated High RPM to verify the regulator was working.


My Issue was the MAF sensor. I replaced it and all is well. 39 bucks on ebay brand new... 195 at autozone...

https://www.hyundaiforum.com/forum/a...1&d=1282753530


2 of our adapters from fuel pressure kit. They fit between the fuel rail and the pressure hose that feed the fuel rail..

fuel pressure gauge adapter
 

Where could purchase the adapter?