6.4L intermittent aerated fuel-no start

Mekanik · March 20, 2014

We’ve got a 2008 F-250 with a 6.4L in our shop that is kind of a problem vehicle. The vehicle will get towed in as a crank-no-start, and it will have air in the fuel system. If the tech opens the Schrader valve it’s like opening a pop can. Once he purges the air the engine will start.

The vehicle will go another 700 miles and then get towed back in for the same problem. Every time the vehicle comes back it has a low ICP DTC and an over speed DTC. I guess the guy does a lot of highway driving. The tech has put a clear hose before the low pressure pump on the frame and there aren’t any air bubbles. He’s also replaced the pump on the frame, the fuel pick up, and the O-rings for the fuel pick up.

Has anyone ever run across a problem like this with a 6.4L? Is it possible air is getting into the high pressure fuel pump? I was also thinking that maybe an injector was intermittently leaking. I’ve replaced injectors before that had a leaking tip, but never one that was intermittent.

Gofaster23 · April 17, 2014

Is the customer running it out of or near out of fuel? Everyone knows the Distance Till Empty is an "estimation" at best, but customer's seem to think it's accurate down to the .1 mile. I've had trucks run out of fuel with 18 miles left on the DTE reading. Maybe it's possible the customer is near empty (light on, DTE under 50 miles) and is parking it on an incline like a driveway. One little sip of air will lock out the system and have air bubbles present at the HP fuel bleed hose. Just a though.

Gofaster23 · April 17, 2014

*thought

Chad_Kelsoe · April 17, 2014

Another tech here had one a few months ago. Hotline finally had him replace the fuel supply line and fuel return line at the high pressure fuel pump and replaced the rubber washers too. They said they had found a few cases where the lines would not leak fuel, but after engine shut down, the seals would allow air to be sucked into the lines. This was after he had installed a low pressure fuel pump and secondary fuel filter hosuing after hotline suggested those. He had the cab off a week prior for an oil cooler job.

lmorris · April 21, 2014

We had one come in like that, would not run and lots of air in the fuel. It was towed to us from the local Indy diesel shop. They just did head gaskets and stuff. Turns out none of the injectors were torqued past the initial 177 inch pounds. They towed it back to there shop.