Air in return line (not from filter housing)

[keleher]

Hi all
Had an issue with excessive vibrations and the engine shaking in start stop traffic, like a sputter but it hasn't stalled so far.
Been going over everything and replaced a fair bit but it is still there. I hooked up some clear hose to the fuel return pipe over the weekend and there was a constant stream of small bubbles (bit bigger than a pin head every cm or 2) with the occasional larger one (m&M mini size). When I ran the fuel leak test or gave it a few revs it would occasionally look like soapy water going through. I thought fuel filter was leaking so hooked up the clear hose from the filter housing to the pump but it was solid fuel. Put on extra hose clamps, looked at lines, even got my mechanic to look at it but couldn't find anything and I'm guessing its not normal and is causing the issues.

Hooked up techstream and rail pressure is spot on, injectors vary from 0.3-1 from cold to running temp the 4 times I've done it and everything else is within spec.

Not sure if it is related but when i first start it up in the morning it idles high (900 rpm) and feels like the power heat switch is on even on a 40 deg day but comes back to the 750rmp after the temp gauge starts to move. Now that it is cooling down <20 in the morning I've tried the power heat switch but it does nothing (thought it took the idle to around 1100), not sure if it is cold enough though.

Anyone have any thoughts before I take it to a diesel specialist and they start replacing everything?

[Thelocalsparky]

Hi all
Had an issue with excessive vibrations and the engine shaking in start stop traffic, like a sputter but it hasn't stalled so far.
Been going over everything and replaced a fair bit but it is still there. I hooked up some clear hose to the fuel return pipe over the weekend and there was a constant stream of small bubbles (bit bigger than a pin head every cm or 2) with the occasional larger one (m&M mini size). When I ran the fuel leak test or gave it a few revs it would occasionally look like soapy water going through. I thought fuel filter was leaking so hooked up the clear hose from the filter housing to the pump but it was solid fuel. Put on extra hose clamps, looked at lines, even got my mechanic to look at it but couldn't find anything and I'm guessing its not normal and is causing the issues.

Hooked up techstream and rail pressure is spot on, injectors vary from 0.3-1 from cold to running temp the 4 times I've done it and everything else is within spec.

Not sure if it is related but when i first start it up in the morning it idles high (900 rpm) and feels like the power heat switch is on even on a 40 deg day but comes back to the 750rmp after the temp gauge starts to move. Now that it is cooling down <20 in the morning I've tried the power heat switch but it does nothing (thought it took the idle to around 1100), not sure if it is cold enough though.

Anyone have any thoughts before I take it to a diesel specialist and they start replacing everything?

How did you go mate? I'm having similar problems but ran the clear line from the tank to the pump, no change! Mine splutters all the way through the rev range but only under load. More air comes in when it boosts? I che he'd pickup too

[keleher]

Nah mate no luck asked a few "experts" but not sure was the answer. They looked over it and run it on the dyno and told me it runs great. Mine runs fine its just when i stop it judders but is very intermittent.