First post here, hope someone can help.
I have a 2009 Citroen Dispatch HDI 2.0 120hp, 135k miles with noisey Siemens Injectors, at least that's what i'm thinking at the mo', I bought it recently and found a tiny amount of swarf in the filter, but history shows a recent HP fuel pump rebuild, so I put an inline magnetic filter to catch anything still in the system, and the rail pressure seems good, so I assume/hope it's 'historical' swarf, and guessed that could cause injector wear/noise.
The engine sounds good at idle, until around 1700rpm ish, but the noise starts at slightly lower revs when warm, it carries on all the way up (beyond 3200rpm), and generally only when the throttle is down, a dab of the throttle and the clatter follows the revs then tails off, even if higher rpm than idle, i.e. when cruising on the motorway.
Listening with a screwdriver in the ear and on the injector inlet pipes, 4 + 3 sounded significantly more clattery (metallic tapping), and no.1 was also quite loud, so I swapped out two on the right of the engine looking at it from the front bumper, assume these are also 1 + 2 in Diagbox?
It sounds pretty much the same after swapping, although I can see in diagbox different % flow corrections, but I don't know what they should be!? Assuming it was 1+2 I swapped, then 4 was the other I thought sounded noisey, but it had a very different (137%) flow correction. Is over 100% good or under 100% for an old injector? Also all four don't add up to 100% average, and 1 vs 4 is quite a high difference, especially now I've swapped 1 + 2 is that normal!? Edit* Diagbox says flow should be between 60% and 140%
My next plan was to swap out the third noisey injector (no. 1) , it's at the other end (cam end) to the two I did swap. Edit* Injectors are numbered 4,3,2,1 looking into bonnet from infront of the van
Before swapping out 2 injectors, at idle:
After I swapped out injectors 1 + 2:
Injector 4 still seems to have quite a high flow rate compensation, so is that one also worth swapping out, or is injector no. 1 too low compared to the others now? (it looked like no.1 had a re-build nozzle kit on it) If swapping the injectors didn't make much difference, am I barking up the wrong tree, what else could it be, hydraulic tappets, still an issue with swarf in the fuel system etc?
It still seems to pull well, with no dash fault lights, but engine does vibrate a bit idleing when cold, and I did notice a puff of smoke before when starting 1st time from cold, otherwise no smoke.
!