Hey,
Not sure if this is the right place to post this but I’m at a loss.
I have a 2007 Mercedes ML320CDI. I’ve had it for 3-4 years now purchased from the original owner.
When we first bought it, the seller was selling it because they noticed when driving by sometimes it would just not accelerate quickly so they took it to Mercedes who said it was the transmission and they would need a new one. This issue was intermittent which my husband noticed when he test drove it, and determined it’s not that so we bought it.
We get home and after a short while he determines it was something to do with the electronic wastegate actuator. He replaced it and it’s been fine since.
Fast forward to last month, I’m driving and noticed that when I get to third gear I no longer have power and it takes forever for me to get home to speed. (1 full minute from 47-100km/hr). My husband checked thinking maybe same issue but said no. Issue was again intermittent. After a couple days it was no longer Intermittent and now permanent.
He used his OBD scanner and it said something about not making boost. P0299 code.
This is where he starts trying to diagnose and repair.
1st he replaced the turbo actuator. Nothing changed so we put the old one back in.
2nd he replaced the MAP Manifold Absolute Pressure Sensor. Again nothing changed so he put the old one back in.
3rd he put in a new turbo intake seal kit and Engine Crankcase Vent Valve. Still not fixed. Left in new parts.
4th he replaced the fuel filter. No change.
Test and inspected the EGR. No issue.
Lastly he figured well it’s the turbo, so we bought a new one, replaced it and then when we went to test drive it he said it ran worse than before (jerky/laggy). Got back and parked.
The next day he went to check it out again and it would start run for one second and then turn off on its own. It will not remain running.
He has confirmed fuel pressure tested and is fine.
Two MAF sensors replaced.
Battery is fully charged.
Have tried disconnecting battery over night then reconnecting to try again with no change
Has 3/4 diesel in the tank. Not the issue.
Has anyone else ever seen this before or experienced it themselves? I’m at a loss and currently have a massive brick in my garage.
Thanks 🩵