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Low fuel pressure warning when cold and getting worse

1693 Views 5 Replies 6 Participants Last post by  PeteK
Hey guys. First post here but been lurking for a couple years. I've got a 2019 platinum that I got last year in February with 26k miles. Now at 66k.

Last winter I remember only once or twice when it got really cold, I would get in after a remote start and would see an error on the dash saying "fuel pressure low". But it never left an MIL on, and drove fine. And then just never saw it again. Until a week or 2 ago. Saw it once or twice at random again in the lower temps, and same story. I thought just some water in the fuel.

Well this Christmas weekend my wife and I took it to Tulsa Oklahoma for the holiday, and it started doing it almost every start. Or at minimum half of them. So I realized now I have a real issue and not just a bad batch of fuel or water in fuel. It made the trip fine with me babying it and nervous since it's Christmas weekend and I don't have another vehicle.

Now that I'm back home in Texas, it's still doing it. Even in the 40s and 50s. I ran forscan and see a P008A code in 2 different places. Both thankfully are for the low pressure pump (I'm guessing in tank?). Truck has 66k miles so no power train warranty left to cover it.

I know that if I don't fix this soon, it will eventually kill my HP fuel pump, and God knows I can't afford that. This is our only vehicle at the moment.

I'm plenty savvy to fix whatever I need to. Question is, do you think replacing the low pressure in tank (or wherever it is) fuel pump will solve my issue, or could something else be the culprit?

I've also been monitoring the desired low pressure vs actual low pressure fuel PIDs as well. Desired seems to be around 64.5PSI and actual is around 63 to 64, but since I've been monitoring this, it hasn't given me the low fuel pressure message even once. Go figure now that I'm actually trying to diagnose it.

I run got shots secret EDT year around and change fuel filters about every 20k miles.

Any advice is much appreciated!
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I am not a mechanic so just a few thoughts that might be of assistance. First, from the Ford 3.0 Coffee Table book I read that the low pressure fuel pump is in the tank and must produce at least 51 psi or you will get the code and warning. The problem is that the high pressure pump must have adequate flow and pressure or it can be damaged, and that is an expensive repair. There is a thread here somewhere on that issue, I will see if I can find it.

Causes for this code may include: Dirty fuel Plugged fuel filter Restricted fuel line (e.g. kinked, clogged, etc.) Fuel pump pickup dirty Unstable fuel Fuel injector defective Weak low pressure fuel pump Sludgy fuel (e.g. old, thick, contaminated)

Font Screenshot Number Terrestrial plant Document

Here are some screen shots from the Coffee Table Book:

Guitar accessory Font Wood String instrument accessory String instrument

Plastic bottle Font Gas Electric blue Auto part

Purple Font Violet Magenta Electric blue

Based on this, I would think it necessary to verify the system is getting 51 psi at all times.

Edited to add: Here is a link to our discussion on the high pressure pump. Adequate fuel supply is a big part of it's longevity: CP4 Failure

So, you could be looking a failure of the low pressure pump, sensor issues, filter issues, electrical issues or whatever. A quick check of both filters for any seepage or leaks would be a first start. I am guessing a diesel tech might put a gauge in line of the fuel after the second filter to verify minimum pressure. Wish I had a quick fix for you. By the way, the Coffee Table Book says once the switch triggers it is supposed to give you the warning, set the code and then derate engine power. You didn't mention the engine derating.
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My truck displayed the "Low Fuel Pressure" warning only once, and that was last week Friday morning when the air temperature had warmed up to -3F (from an overnight low of -8F) shortly after starting the truck and while driving low speed in town. I assumed the fuel was too thick (gelling) because of the low temp so I stopped and added some Power Service fuel supplement with anti-gel (the Power Service supplement in the white bottle). The low fuel pressure warning didn't return, no codes were set, and the engine power was not derated.
I have been using the Power Service fuel supplement with anti-gel with recent re-fueling in an attempt to prevent fuel gelling. I will be keeping an eye on this.
Found this in the on Pages 11-12 of the 2018 F150 Warranty Guide

(4) Your vehicle’s direct injection diesel engine and certain engine components are covered during the PowerStroke Diesel Engine Coverage Period, which lasts for five years or 100,000 miles, whichever occurs first. The following parts are covered during this extended coverage period: the engine, cylinder block, heads and all internal parts, intake and exhaust manifolds, timing gear, harmonic balancer, valve covers, oil pan and pump, water pump, fuel system (excluding fuel lines, fuel tank and frame mounted fuel conditioning module sometimes referred to as the frame mounted pump/filter/water separator or frame mounted fuel filter/water separator), high pressure lines, gaskets and seals, glow plugs, turbocharger, two-stage turbocharger assembly, turbocharger actuator, powertrain control module, high pressure fuel injection pump assembly, injectors, injection pressure sensor, fuel rail pressure sensor, exhaust back pressure regulator and sensor, exhaust pressure sensor, manifold pressure sensor, intake air temperature sensor, crankshaft position sensor, camshaft position sensor, accelerator switch.
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I would start with a fuel filter(s) change. Some people claim that after fuel gels and waxes in the fuel deposit on the filters, the filters should be changed. I've also seen those that claim there is no need. It sound like you may have already purged any wax based on the low-pressure warning going away.

My general practice is to add anti-gel anytime I am in an area where the temperature is substantially below the normal temperature for that region and time of the year. So -30 in northern Minnesota in January might not need an additive, but 0 degrees in March in Detroit might. I've learned this the hard way.
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Excellent replies from Dunrollin and jmperlik and beaker. Don’t start by “throwing parts at the problem.” In addition to the items Dunrollin listed, the pressure sensor could be bad. I’d want to put a gauge on the fuel line somewhere and check that when you get the low fuel pressure warning. At least see if the fuel pressure is reading comfortably above the minimum spec when it’s idling, and under high load.

Did the warning occur when the engine was under high load, or light load, or randomly?
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