About a week ago I had all 4 injectors replaced with new ones on my Astra CDTi after about 6 months of it frequently regening itself, lots of smoke, bad smells etc. The garage I took it to tested the injectors and all 4 failed so all had to be replaced. The also ran diagnostics and a forced regen once the new ones were in.

Car seemed a lot better for about 4-5 days, no smells, no smoke etc, but in the last 2 days it's gone back to trying to regen itself pretty much every day, lots of smoke, smells etc.

The injectors definitely needed replacing but it doesn't seem to have solved the problem. My question is - how does the car decide it needs to regen and why would it be doing it so frequently if the injectors are now fine?

The garage did say that I'd probably have to do about 400-500 miles to be sure it was just more than the injectors and there is diesel and other crud in the DPF from when it was over injecting, and this also caused the regen to be interrupted on most occasions (pre the injectors being changed) so the DPF wasn't actually getting a good clean out. Does this sound right? Possibly it's actually okay and it's just residual soot / ash / diesel in the DPF and this needs a few hundred miles and several more regens to clean out, or is there likely to be another underlying problem that needs fixing???

*edit* thought it best to mention that since the injectors were changed I've taken it out on the motorway a few times, running it for about an hour in 4th gear and 2.5k to 3.0k revs. It hasn't tried to regen on the motorway as far as I can tell, it keeps doing it once I'm back on the urban roads doing like 20mph, which is somewhat annoying...

Edited by Richard_R on 23/10/2024 at 19:51