How do you test fuel pressure on gdi engine?

I have a 2012 kia rio. I’ve never worked on a gdi engine. How do you test the pressure? Is it done with a Shrader valve? Does anyone know how high the psi should be?

Kia Rio: Fuel Delivery System - Engine Control / Fuel System - Kia Rio UB 2012-2020 Service Manual (

Kia Rio: Fuel Pressure Test (Low pressure system) - Fuel Delivery System - Engine Control / Fuel System - Kia Rio UB 2012-2020 Service Manual (

The direct injection system runs hundreds of psi, the low pressure supply system just brings fuel up to the injector pump. High pressure is tested by looking at the pressure reading in the data lines on a scan tool.

Is there a way to test the low pressure system? I’m trying to see if the fuel pump or filter is bad.

Just saw your links above. Thank you.

Yes there is, as you saw by the link @weekend-warrior posted.

Why? Is there some sort of issue with the way the engine starts or runs? Is there a fault code?

No codes. It seems acceleration in lower rpm is really sluggish. At around 3k rpm it seems to accelerate normally. I really have to press the pedal to make it accelerate.

I think my gas millage is lower than it should be also.

If you have adequate power at 3000 rpm and high speeds it’s unlikely you have a fuel supply issue. Engines need more fuel at higher rpm and under load than they do at idle and part throttle.

You’re going to need some live data from a scan tool.

That little engine is rated at 115 lb-ft of torque @ 4200 RPMs. In comparison the Dodge Neon engine has 130 lb-ft torque @ 4600 RPMs. This car was not designed for performance.

Your fuel economy will improve next month when the burden of air conditioning s reduced.

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OP says power feels down. Now. Compared to previously? Or it has been underpowered since day 1?

Me thinks this is a case of buyers remorse more than the vehicle having problems. The thing is probably getting MPG it should and it is 9 years old with unknown miles .

The car is definitely slow. It’s just strange how I get little acceleration when pushing the gas till about 1/2 to 3/4 of the way down and it takes off.

I knew it was going to be slow. It just doesn’t accelerate smoothly at all. It’s dead slow taking off then accelerates really quickly. It’s pretty dramatic. There’s no way it’s normal.

Did you test drive this before you bought it ?