Reconditioned engine first start, running rough

[coconup]

Originally Posted by ngoma

Not understanding this. The idea is to install the low pressure fuel pump at the fuel filter inlet. This pressurizes the entire fuel circuit between from the filter (including the fuel filter) to the IP (including the IP)(at least to its centrifugal vane pump). Should be no chance for air intrusion EXCEPT: possible scenario of clogged fuel pickup in tank?

Yes that is pretty much the setup I had all along: hand pump before the filter inlet. Air must have come in from somewhere at the filter (either the outlet or the fuel preheat plastic valve - aka the knackfrosch). Today I took the filter out, replaced all pipes going in and out of it, replaced the o-ring on the plastic valve and bubbles are finally gone.

Earlier I tried the trick of creating a vacuum at the IP inlet with a hand pump, and the the vacuum would hold. I could not hear any hissing sound from anywhere, so I concluded the IP and everything downstream from the filter is tight.

I have now put the hand pump between the filter and the IP just to check that the filter outlet was not the source of the air ingress, but I will move it back to the filter inlet eventually. The important bit is bubbles are now gone

Originally Posted by ngoma

Sorry at work and can't view YT videos. Thought you checked the injectors? Is the IP dialed in (fuel screw, and LDA preloads)?

I checked all injectors, yes, nr. 6 is still installed and that one had a slight drip before opening pressure. But I doubt that would be the cause of the final cloud of smoke in the video. As for injector 1 (the totally screwed up one), I already replaced it with the best of the bunch I had left from the ones I originally took out.

The two new injectors are still on their way, they will arrive tomorrow.

I have not done anything to fuel screw and LDA preload, they are set as the workshop set them when they reconditioned the pump.

I had the fuel screw on my list of suspects, but I'm not sure that would explain rough-ish idle. Also as a side note, the turbo is currently disconnected from the air intake, so I'm assuming the LDA would just sit there at any RPM. I'm not very familiar on how to tune the LDA and smoke screw though, so these two might very well need some adjustment.

When you have a minute to check the video, that might make it more clear what the remaining symptoms are: bumpy idle (but better than before) and clouds of smoke when revving.

Originally Posted by ngoma

Did you strip the threads in the block or the teeth in the bolt head 12-point inhex?

The teeth, it was one of the hard bolts to reach and one of the first ones I torqued.. the bit didn't sit all the way down into the bolt head and I didn't notice, so I screwed up. Afterwards - and after a lot of fighting - I was able to force the m12 bit to the bottom of the bolt head, so I'm hoping I can now pull it out without it stripping again. I will then replace it with a new one a torque it fully.. assuming I don't have to take out all of them and repeat the whole torquing from scratch (seems overkill?).

As you can imagine, I was beating myself really hard about this.. but now that I got the bit to fit the bolt head again I'm a bit more optimistic.