Hi all! I have a MK4 Mondeo, 1.8L TDCI. My turbo seized resulting in the bearings blowing and oil being spewed into my air intake. After a long and tedious couple of weeks, a new turbo was fitted and my air intake cleaned of oil. However, with this new turbo I have no power until:

2,800 RPM 1^st Gear

2,700 RPM 2^nd Gear

2,500 RPM 3^rd Gear

And so on and so on. before the turbo blew, I had the turbo kick in around 1,500RPM. I took my car to get remapped in an effort to fix the issue (assuming it was an ECU issue, also because fun) and a dyno test showed 40bhp at 2,700RPM which then shot up to 168bhp at 2,850RPM when the turbo kicks in. The before and after dyno runs both show next to no power before 2,800RPM so the issue existed before the map leading me to believe it's not an ECU issue. The result of the low boost pressure was my car going into limp mode after 20-30 minutes of cruising. The EGR valve was stuck and knackered so I just blanked that off for the time being which has helped with the limp mode, boost pressure warning and insane turbo lag.

Relevant info:

1. The garage that fitted the turbo insists the turbo is functioning fine and doing what the ECU is telling it to do.
2. The tuning place ensured me the issue is not ECU related.
3. I have no idea whether the turbo is OEM or not as the man at the garage doesn't remember ever doing the work. He's old so I'm not surprised and I should have asked when I picked the car up.
4. I had someone look at the ECU, to which I was told thee ECU was telling the turbo to do what it should as per any diesel car.
5. When I shift from 2^nd to 3^rd for example, even though the shift puts me well within the turbo range, my turbo still takes 1-3 seconds to produce applicable pressure.

I think I need a professional eye to look at the turbo to make sure it's been set up correctly by the garage but that gets... costly. A part of me is very annoyed I didn't just take it to a ford dealership to get a proper job done.

Can anyone offer any advice at all? Anything I can do as a non-mechanic? I know generally how all this stuff works so adjustments and small things I can do but something on the scale of removing the turbo is out of the question.

Thanks in advance to anyone who responds to this. So far it's stumped a lot of people. If you need any more info, please ask.

Start with basics. In plug the MAF sensor. Then go for a drive. It may well be he maf sensor playing up.

Sounds like a very stiff turbo needing lots of pressure to spin.