[izy521]

Hello! I have a 2014 Forte Koup 2.0L GDI (114,000 miles), but I posted here because I don't think this is specific to the Koup.

A couple of days ago my car started sputtering, the RPM needle was dancing and it was definitely having trouble running. No codes were thrown but I pulled over anyway and got a tow back home. While I was waiting, I noticed I couldn't hear the fuel pump activate like I usually do and used a Bluetooth ODB2 reader and an Android app called "Car Scanner ELM OBD2" to read the live values. When turning my key to the ON position my "Fuel Rail Pressure" raised to about 40psi, and then fell to about 30psi, over the course of 2-3 minutes. I wasn't able to start the engine, but it looked close to the values listed here: Kia Forte: Fuel Pressure Test - Fuel Delivery System - Engine Control / Fuel System - Kia Forte TD 2014-2018 Service Manual (323 ~ 363 kPa (3.3 ~ 3.7 kgf/cm², 46.9 ~ 52.6 psi) ). I thought it was just slightly low and I needed to replace the fuel pump in the back.

The next morning, I turn the key to the ON position and I'm able to hear the pump, the "Fuel Rail Pressure" reading on the app is now at about 1500psi though! When I start the car, it actually runs, but the idle pressure is about 560 psi, which is a lot more than what's listed on that page. My plan is to still replace the fuel pump assembly in the back, as some people in a car-centric Discord told me I may have had a clogged fuel filter, and a new one was about $100 on RockAuto.

What I'd like to know is if this is a normal pressure reading for a GDI engine, as I've heard fuel pressure may be higher for them, and if anyone has the same engine, are you able to share your fuel pressure readings?

Thank you

 

[izy521]

This is what the app looks like and shows, on my phone.

 

[PLP]

It is a high pressure (GDI, not MPI) injection, Direct Injection.
Pump will push maybe 50 psi... and then you have a high pressure pump that is powered by the engine itself, mechanically. Pressure at idle can be 300-500 psi. It may vary a little, but then when you are driving you can easily see 1500 psi.
You know, it has been a while, but I recall on TGDI (1.6) would spike to 2500 psi... idle would be low like yours.

 

[izy521]

It is a high pressure (GDI, not MPI) injection, Direct Injection.
Pump will push maybe 50 psi... and then you have a high pressure pump that is powered by the engine itself, mechanically. Pressure at idle can be 300-500 psi. It may vary a little, but then when you are driving you can easily see 1500 psi.
You know, it has been a while, but I recall on TGDI (1.6) would spike to 2500 psi... idle would be low like yours.

Thank you for your response and for confirming that!

The app does mention it's "Fuel Rail Pressure" so I guess context clues would suggest that it measures the pressure from that high pressure pump right before the fuel rail and not the pressure from the pump in the back. It is starting to sound more and more like the rear pump had an issue and wasn't able to deliver fuel like it should. I just wanted to clear up any confusion I had seeing the values on KiFomanual.