Fuel cackle, runs rough, clears up, then repeats.

[lmorris]

2010 F350. Starts up fine with no smoke. With in a few minutes of running it will make 2 or 3 sharp cackles then run rough for about 5 seconds then smooth out, will continue this cycle no matter the engine temp. Codes pulled P0281 #7 contribution, P120F fuel pressure regulator excessive variation, P2291 icp low cranking. Power balance has #2 shoot up +20 and #7 drops right off. Shut down #7 and it still acts up and #2 shoots up. Shut down #2 and it still acts up but #2 goes from -40 up to 0, and #7 will drop right off. Relative compression has #7 at 14%, but I am thinking that is a result of #2 slowing it down. Suspecting #2 injector is sticking and causing all my issues. In the process of removing the left valve cover, plan on removing glow plugs and cranking it with the injectors unplugged to look for any fuel coming out of the glow plug hole. Never had this kind of failure, mostly no starts with stuck open injectors. Is #7 dropping off just a result of #2 over fueling?

 

Edit: No fuel key on, cranking. Suspected as much, think it only acts up when running. Fuel is clean, no rust in filter housing.Took a sample from the fuel rail, has a few metallic flakes maybe 10 or so. My gut says to quote the entire system, but it doesn't fit the "Typical" contaminated fuel scenario.

 

Edit: No compression on #7, valves are working. Really threw me sideways because it wasn't running like it had a dead hole.

[tonybullitt]

I got one that runs very similar. The one I have is from another shop, story is they just rebuilt it. It does the same thing runs ok then fuel cackle pours fuel smoke then clears out then repeats. This truck is a hacked up pile of junk. They brought it in before I looked at it did fuel contamination check found debris. They picked truck up then brought back saying same concern. I ran self tests got on demand frp sensor code monitored pids koeo frp fault pid shows yes fault, frp showed 11,322 psi, desired showed 0. They picked up, put frp sensor in then brought it back. It has been a disaster. I am sure they didn't replace fuel rails. The so called tech claims he cleaned them.

[cbriggs]

Did you happen to look at the cylinder fuel trims Leon?

[lmorris]

Did you happen to look at the cylinder fuel trims Leon?

The fuel trims matched the power balance, #2 would go negative and #7 would go positive(a lot) when it stumbled, then go back to zero when is smoothed out, the rest were 0. My though now is the metal in fuel system is the cause of the engine failure. Still waiting for an answer on the quote. Still baffled that it was pretty smooth when it wasn't acting up, given the dead hole.

[tonybullitt]

Got ok to look at the fuel cackle one I had more. I checked comp on dead cyl 8 and it has 350 psi, I figure fuel wash. (Story I was told is engine just had pistons and rings put in it for melted pistons)   I removed LH valve cover took fuel sample. Its full of debris. This is the 2nd set of injectors he put in it. I had told him before first set to replace fuel rails.

[tonybullitt]

Check this crap out. When I got valve cover off I seen cylinder 8 hold down bolt. I removed the injector obviously loose the copper washer is black.

[tonybullitt]

Head is ruined. Appears to be an epoxy he tried to reattach it with. Wonder why he thought a longer bolt and epoxy would work?

[tonybullitt]

Check out how he had fuel cooler hoses.

[Brad Clayton]

[lmorris]

Update on mine. What I thought was a fuel cackle turned out to be some funky valve noise, pinpointed the noise to be coming from #7 area, the one with very low relative compression. Manual compression has #7 at zero and all others 275-290. We think one of the valve is sticking. Still requires a tear down to be sure, but my guess is a valve has been tweaked at some point by the piston. To intermittent to be a burnt seat. Checked fuel rails and there is metal in the rails. Quoted a drop in and he is buying a new truck instead.