1995 F-250 5.8L EFI, 90,000 original miles (yes that’s correct ). Stock. Dual tanks. For years, when on the rear tank and accelerating from a stop, truck would act like it’s running out of gas, stutter and occasionally stall. But if I quickly switched to the front tank, it would keep running and I could switch back to the rear tank and it would operate normally (no stutter or stall). I did replace the fuel sender/pump in the rear tank about 5 years ago as well as the fuel filter.

Recently, the front tank stopped supplying fuel. When I switch to the front tank, the truck immediately stutters and stalls, like it’s running out of gas. Yesterday, I pulled codes and got 542, Fuel Pump Secondary Circuit Failure. It actually flashed 111 about 7 times, then 542 twice. KOEO and CM. Codes appeared whether fuel switch was on front or rear tank, which may be normal.

I read elsewhere that code 542 means that the engine is seeing more resistance in the fuel pump circuit than it wants and there could be an issue with the ground. That post advised checking the ohms at the relay, inertia switch and fuel switch, but this is where my skills become limited. I checked the leads against the ground but how do I interpret the readings? Should I be expecting little to no resistance (0 ohms)? What reading should I expect if checking a hot (positive) lead against ground (or should I even do that, closing that circuit)? I realize that I’m trying to isolate where in the circuit the extra resistance is occurring, but then what? Bad connections? Replace wiring?

FWIW, at the fuel selector switch, only the yellow/white lead (feeds instrument cluster) shows any resistance. The inertia switch leads showed little to no resistance. The relay gave me mixed readings but could be I did it wrong. I haven’t checked leads at the tanks but plan to pull the bed off today and do so. Pulling the bed will be easier (for me) than working from underneath plus I can better check all the connections.

I also tested the relay, connecting the 85 and 86 leads to power, hearing the click and checking the ohms between leads 87/87a and 30. It was working.

I also checked the ohms on the switch between the various leads, flipping the selector and it seems fine.

I have not yet checked fuel pressure at the rail as I have to rent or buy a fuel pressure gauge.

I do not have a Dual Fuel Reservoir (DFR) as best I can tell. The fuel senders/pumps reside in each tank.

Any tips, advice and help is appreciated at diagnosing this fuel issue. Again switching to the front tank makes the truck stall as if out of gas. The rear tank has historically had the same issue but more intermittent and seemingly self-corrects. Thanks.
Scott

 

Sounds like you need a front fuel pump to me. Very common on these trucks.

 

90k means nothing if it's a hard working farm truck. Matter of fact, it probably means it's got a lot more wear than that.

 

+1 for needing a new fuel pump
Find a new Ford pump for the front tank
Most (some) of the aftermarket ones are crap and the one way valves fail quick / often

 

Closing the loop on this project. I took the bed off, pulled the front fuel sender/pump and found it full of a reddish, sand-like grit....likely rust particles from the 29-year old tank. Sooo...now I have two new fuel tanks (the rear one was just as bad), new mid-ship fuel sender/pump, a new rear pump (sender was newer) and new fuel filter. While I had it apart, I also painted the frame with Eastwood rust encapsulator to deal with the surface rust (washed and degreased frame first). I also replaced the rear diff cover with a aluminum cover with heat fins (this cover was originally going on my Excursion but never did, but looks good on this truck). The truck is all back together and running fine. There's a few new quirks: 1) the fuel gauge pins all the way to the right (past Full) when rear tank selected. Gauge works fine for the front tank. Fuel level sensor has good ground and reads proper voltage. 2) there's a mechanical bump coming from the rear diff/axel as if the limited-slip feature isn't working. I filled diff with Mobil 1 75w-140 oil until it flowed out of filler hole. I haven't investigated this one yet and may be the topic of a different post.

 

Thank you for your input man, we really needed to hear that lol

Last time I had a fuel circuit failure on my '92, I ended up jumping the wires on the tank selector and it worked. Got a new selector switch and all was right with the world. Other thing to check is the inertia switch, you can jumper it in order to take it out of the equation for diagnosing purposes.