D5 (D5244T to 2005) ECM6805 Cured?

[GSMGuy]

Ok, further on from the rough running, which is now fine - See other thread..

Today I set about finding out why I appear to have no low down boost, and am getting "Engine Service Required" EVERY time I go over 2500rpm, stored code being the good old ECM6805...

So, armed with my shiny new Mityvac kit - I set about doing some testing....

First, I pulled off the vacuum takeoff from the vac pump, and popped on the mity... Vacuum is being produced, but tbh - not much, and it's not steady, although this may just "build up" in use...

Next, I connected the mity to the hose taken from the pump, and proceeded to apply a vacuum... Or at leat I tried, engine off or running, no vacuum could be produced,,,

Next, I checked that the front engine mount held a vacuum on it's own, which it did - Now the rear one is a pig to get to, so whilst studying the pipework, it appears that the vac from the pump tees off just below the EGR are, one feed going to the solenoid on the front of the airbox, the other to the turbocharger control solenoid located on the block, just below the common rail - So, the valve on the airbox ONLY controls the engine mounts.... Hmm...

Pulled up this valve, and detached both the vacuum in, and the mounts out pipes.. Tried a vacuum on both, the engine mounts both held, and could be heard to audibly "click" when vacuum was applied/released - more noticeable with the engine running... On the other pipe, no vacuum could be held...

Now I have said all along that I think it's a vacuum issue, so next I disconnected the output pipe (goes to the vane actuator on the turbo) from the turbo control solenoid, and applied gradual vacuum - I could actually heatr the actuator moving on the turbo - Time for some inprovisation - Applied 15" vacuum to this, and secured the mity under the bonnet, plugged the other pipe and went for a spin - BINGO takeoff was immediate and boost was plentiful.... So now, I just have to find the leak...

Mike