LFX V6 - PO228C code

[67-LS1]

I got a PO228C today in my LFX powered 66 Chevelle. While driving it felt like the electronic throttle pedal failed. I read the codes and it gave me this code.

This was the first drive after having my dashboard out to chase some rattles but that shouldn5 have anything to do with it. The car sat for about a month total.

When I fist started it after the dash reinstall, the primary fuel pump (mounted in the frame rail under passenger door) sounded different. Like it was struggling. The high pressure pump also seemed like it might have been louder. Not sure about that. But it started and ran. It got me about 9 miles into my 10 mile ride home.


So PO228C indicated that the high pressure fuel pressure regulator is seeing low fuel pressure. I haven’t had a chance to diagnose the root cause yet but I’m wondering if the failure of the low pressure pump could give a low pressure condition on the pressure side of the high pressure pump. Any guesses?

If so, wouldn’t a car that runs out of gas also get a PO228c code?

I’m hoping it’s something easy external to the engine.

[co14camaro]

The OEM LFX pump is in the tank to ensure its got plenty of fuel it can grab. I'd make sure your external pump is pretty close to the tank and is lower than the tank to help with gravity feed to prime it. Chances are you got vapor locked and the non high pressure pump starved itself which caused the high pressure pump to starve.

[67-LS1]

Thanks. The pump is below the tank level but the fuel line from the tank to the pump goes up and over the rearend. It’s been working for a few thousand miles so I’m not sure what would have changed.
I’m heading to my shop today to try to diagnose the problem. I’m hoping it’s something super simple.

[AlanRubin]

There is no P0228C code.

It is either P228C or P0228.

P228C Fuel Pressure Regulator 1 Exceeded Control Limits - Pressure Too Low
-or-
P0228 Throttle Position Sensor/Switch C Circuit High Input

[67-LS1]

Your correct. It’s P228C - Fuel Pressure Regulator 1 Exceeded Control Limits - Pressure Too Low.
And the issue seems to be with my primary fuel pump. Mine is mounted along the frame, not in-tank like a Camaro would be. It’s getting power but sounds like its struggling. Like maybe it’s getting to low or voltage Burt it’s not. 12.2 key on. I can’t check it running because it won’t start.
There is a filter before it (and right after it) and the tank was professionally cleaned when I added a return fuel port to it so hopefully it wasn’t trash in the fuel.
New pump should be here today or tomorrow.