2019 Accent fuel issues

Maintenance/Repairs
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2019 Accent with 6spd manual just under 79,000 miles.

A few months and likely a few thousand miles ago I noticed the engine stumbled and had no power when I tried to open the throttle going slightly downhill at 30-40 MPH. I downshifted and it went completely back to normal so I shrugged and went about my life.

Coming in to work thursday on an interstate the engine light started flashing but I didn’t feel or notice any issues, I backed off and it the light went out and all seemed normal. For another 10 miles I didn’t notice an issue but after getting onto a back road I noticed it running really rough at lower rpms. Anything below 3K was pretty bad but above at light load seemed alright.

I made it to work by going easy on it and staying in a lower gear and going easy. When I parked I opened the door at work to give a listen and could smell unburned fuel so I assumed a cylinder wasn’t firing.

I replaced all 4 spark plugs and 1 coil during lunch as the computer gave me a misfire on cyl 1 code at that time. No dice. No change at all.

Now I have multiple misfire codes as well P0191 and P016F and my Ultragage is showing the fuel rail pressure between 40 and 50 PSI. I used to run around 800 PSI idling, 2800 under load.

The car starts completely normal, but dies a few times shortly after until it gets a little warmed up, then it seems to idle ok but you can’t open the throttle much at all.

I replaced the HP pump this morning. Still no change. I did notice the FR pressure is between 40-50 PSI idling, but I slowly brought it up to 2K RPM and the FR pressure climbed to 60 PSI and didn’t drop when I tried to open the throttle rapidly making it bog / die.

I’m using an Ultragage which is all I have to read OBD2.

Right now I’m at a loss. It appears the FR sensor is changing some and working and it’s matching what I’d expect the tank pump to feed but it seems almost like the computer isn’t controlling the solenoid on the HP pump at all

Is it likely the computer has locked out the high pressure pump for some reason and if so, why?

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When that happens, you stop the vehicle and shut it off and call for a tow.

A flashing Check Engine light indicates a major misfire is occurring.

This can result in damage to engine and/or the catalytic converter(s).

Tester

1 Like
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Thank you for responding Tester.

Understood.

Except that it went out completely and I could tell it was running smooth, there was no major misfire at that point. Honestly, I didn’t feel one while it was flashing, but I’m assuming it was likely happening no matter how small. They’re hard to miss on a 4 cylinder.

I just pulled the battery cable for a half hour and everything is back to normal.
Do the computers lock out the HP solenoid under some conditions and need to be manually reset?

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The low fuel pressure may indicate one or more fuel injectors are leaking on the GDI system.

Have the vehicle towed to the dealer to confirm.

Tester

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No experience w/you car or engine, assuming this is direct injection gasoline engine, but 40-50 psi at the fuel rail seems ok for many fuel injection systems. Yet you say you normally measure 800 psi. Not sure I understand what you are sayin there. Do you mean the 40-50 psi is what you normally measure at the fuel rail, and 800 psi is normal for after the high pressure pump? If so, what are you measuring after the high pressure pump now?

If fuel pressure is too low, hard to understand what’s causing the fuel odor? Unless there’s an external fuel leak. If fuel pressure was too high, that might cause too much fuel to be injected, and a fuel odor from the exhaust pipe.

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I’m sorry for the confusion.

The exhaust stunk like fuel nothing else.
It’s a direct injection setup. Fuel rail pressure is normally 600-2800.

After replacing the high pressure pump it still remained low, 40-60. After disconnecting the battery for 30 minutes receiving is back to normal and running beautiful.

I don’t get it.

Do any manufacturers lock out the high pressure pump under certain conditions and would disconnecting the battery be enough to reset it?

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This sounds like a sensor or computer problem. Or you mis-interpreted your scan tool. I do not believe that a DI engine could start or stay running at all if the fuel pressure was really so low. On older cars, with TBI or port fuel injection, sure, the fuel rail pressure might be in the 40 psi range, but on a DI model, no way.

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That’s what I originally thought but apparently some if not all DI cars can “run” with just the low pressure pump.

Mine certainly didn’t run good, but it could start and idle pretty much normal just as long as you didn’t touch the throttle.

It seems to be a built in limp mode to make it so you can get the car off the road etc but barely.
I’m doing a very early oil change today to get the fuel diluted oil out of it. May be completely unnecessary after driving it twice and getting it warmed up good but since I’m unsure I’m doing it anyway.

For those interested, here’s how the HP pump works and how the computer can control the pressure. It’s a very simple setup, but it needs to work almost perfect all of the time.

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If an injector were faulty & leaking fuel into a cylinder all the time , that could prevent the fuel rail pressure from building up to spec, and too much fuel injected, resulting in gasoline odor from tailpipe. Sort of like if you have a balloon with a big leak, you can never pressurize it no matter how hard you try to blow it up. The air goes out as fast as you blow in.

So I’m guessing either faulty injector, or electronics problem resulting in injector(s)being pulsed on too much.

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Wait a sec! Since it has spark plugs, it’s not a diesel. If it’s not a diesel, how can you possibly “used to run around 800 PSI idling, 2800 under load.”?!?
40-50 PSI sounds about right. I don’t have specs but from old days, I recall chevy blazer with “octapuss” CPI spec called for 41. At that time, vw required about 50. I’d say fuel pressure is not your issue. Sounds like CPU…

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Diesels run much higher than 2800 psi.

I’m not sure how it’s 2022 and you’ve never heard of gasoline direct injection.

It’s not a 1990s 4.3 Blazer.
It runs almost 2900 psi at times.

1 Like
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Yeah… I’ve been out of trade for quite some time.
My apologies.

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Tester

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For what it’s worth I’ve put 270 miles on the car since changing the HP fuel pump with no issues.
The fuel trims have settled back down to normal and my average gas mileage is back at it’s normal 48 MPG.

I changed the oil yesterday just to get any excess fuel out of the crank case.

2 Likes
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OP has direct injection engine. So for fuel to flow from injector to the inside of the cylinder, fuel pressure has to be high enough to overcome the pressure inside the cylinder at full compression. If configuration is fuel rail, injector, cylinder, then fuel rail pressure must be very high. If high pressure pump is between fuel rail and injector then fuel rail pressure could be similar to non-direct injection engines.

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You are correct - I have overlooked that. Stand corrected.

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nofyfb_180405 Iapologize if I came across as rude before.
I was a bit stressed from work.