2014 DF175 Issue

[lingcod]

50 hours, fly-by-wire, been sitting for last 6 years. Did water pump service, changed oil/filter, changed low pressure fuel filter. Drained all the fuel from tank, full fill-up with fresh gas.

With fingers crossed, backed her down the ramp. Started fairly easily but ran rough, ostensibly due to the old fuel in the line. After a few minutes, suddenly ran much better though not absolutely silky smooth. Over next ten minutes, gradually increased rpms to 2,800-2,900. Still okay. But trying to advance higher, it would cough, sputter and immediately lower its rpms. Tried running longer at around 2,800 to try to clear things out; still couldn't advance to higher rpms. Same problem.

I did not change the plugs. Fouled plugs?

Please don't say injectors or a fuel pump...

I didn't look specifically, but didn't notice any codes come up on the gauge.

Brand new here. Thanks for the help!

[artdf175]

plugs are a quick check
get a manual to help you
you didn't mention the high pressure fuel pump. Did you drain fuel from that and the fuel rail?
The high pressure fuel pump has another filter in the bottom. it is easy to get to and clean and if you didn't take that apart and clean it you would have missed a big part.
then-- take a 5 gallon tank and mix one of the cleaners like sea foam double strength and run a good gallon through the engine .. can put the rest in your fuel tank after you get the engine running properly
Art

[lingcod]

Planning to change the plugs tomorrow.

Did not drain fuel from VST/high pressure fuel pump or the fuel rail. Wondering if the first 10 minutes or so of running rough used up the old fuel in the rail and the VST since there was a marked difference (and rather suddenly) when it (mostly) smoothed out?

If not plugs, my guesses would be either a) clogged screen at bottom of high pressure fuel pump, or b) high pressure fuel filter, or ???

[Moonlighter]

Answered you over on your ThT post