Hmm, missed this originally. In my experience running on veg oil (fresh at least) works well for the emissions test and our Xantia always flys through. You do go through a few fuel filters in the first few hundred miles because it cleans all the gunky residue out of the whole system too, only issues I've known it cause is blocked filters while it does it's thing (temporary inconvenience, just carry a few spares and a 4mm allen in the boot) & harder starting in winter (add up to 15% petrol or mix 50/50 veg/diesel) plus if you let them sit too long with SVO in the pump it can gum up pretty bad but then, so can modern diesel too. Again, in my experience.
brown/greasy and lumpy sounds like either badly filtered (not sub 1-micron) or wet waste veg oil, or possibly diesel bug infestation although without seeing it, hard to say & maybe just a really overdue filter job.
Glad it's sorted now, it's surprising how lazy and bodgy some "mechanics" can be. Strange thing is, it wouldn't even save them any time/effort as I Bet it would've passed fine after a good thrash and new air filter. Instead they spend probably longer and definitely much more fiddly time diddling with the pump...
The "real" bodge to pass the smoke test on a marginal engine is simply to back the throttle cable adjuster off until the engine only hits about 4000rpm. (maybe less maybe more, just as long as the tester can hear it to rev hard) Takes 30 seconds (a couple of minutes if you have to readjust a few times to get it right) and can be undone just as simply as moving the clip back to where it belongs).
brown/greasy and lumpy sounds like either badly filtered (not sub 1-micron) or wet waste veg oil, or possibly diesel bug infestation although without seeing it, hard to say & maybe just a really overdue filter job.
Glad it's sorted now, it's surprising how lazy and bodgy some "mechanics" can be. Strange thing is, it wouldn't even save them any time/effort as I Bet it would've passed fine after a good thrash and new air filter. Instead they spend probably longer and definitely much more fiddly time diddling with the pump...
The "real" bodge to pass the smoke test on a marginal engine is simply to back the throttle cable adjuster off until the engine only hits about 4000rpm. (maybe less maybe more, just as long as the tester can hear it to rev hard) Takes 30 seconds (a couple of minutes if you have to readjust a few times to get it right) and can be undone just as simply as moving the clip back to where it belongs).