Boost Pressure Difference: Target vs. Actual

Hello everyone...

Now that I finally have a laptop again, I participated in a lock-in.

My target charging pressure is about 0.2 bar lower than the actual charging pressure.

'I'm maintaining a constant speed of 100 km/h using cruise control. The target pressure is 1479 mbar, the actual pressure is 1275 mbar, and the clock speed is 32.5%.'

The log file is located at www.mhernach.com/tdi/log.xls.

What could the problem be...?
I've also been having this problem for a while: when accelerating, the car repeatedly releases the throttle, and the boost pressure fluctuates between 1.9 bar and 1.6 bar.

Best regards,
Michael

1475 millibars is one thousand four hundred... megapascals. 1.4 gigapascals is quite a lot of pressure; not even an atomic bomb can achieve that (just kidding).

Your turbo isn't engaging at all.
If he hadn't even managed to achieve 1800 mbar, I would have said: "Someone stole that from you, you don't have any pressure at all."

"The 32% represents the lower limit of the boost pressure regulation and means 'Hey turbo, give it everything you've got.'"

It's possible that your wastegate is "stuck open." Grab a large syringe and FORCE some air into the pressure sensor. Yes, force it, because we don't have a variable geometry turbocharger (VTG)!
Here, the wastegate should open and then be closed again by the spring force. In the resting position (closed), it shouldn't be possible to push it closed any further. For example, if you press on it with your finger.

If something were broken in the turbocharger's coolant hoses, your boost pressure would become too high.

Is the overall air intake path clear? Is there a potential leak somewhere in the boost pressure system?


If necessary, you'll need to remove the four screws connecting the turbocharger to the exhaust pipe. This will give you direct access to the wastegate. It must be sealed when the engine is off.

Hello mhernach,

At first glance, it appears there's a defect in the air system under partial load. At 120 km/h, it should reach its target value, which it definitely is within the normal range, and it also has sufficient exhaust energy. The EDC is also functioning correctly. To rule out any influence from a potentially faulty EGR system, I would recommend logging the EGR measurement blocks and the fuel injection quantity again.

Do you have any error entries in the system log?

That leaves you with a whole range of potential issues, from EPW errors to leaks on the pressure side, all the way to a faulty or dirty pressure sensor. However, there are plenty of technical articles and forum threads available to help you troubleshoot those specific problems.

Please search for "1Z charging pressure regulation deviation".

Do you have a VTG or a wastegate ATL? I'm not very familiar with the 1Z engine in Ford vehicles.

'The AGR valve is stuck, and the hose connected to it is also blocked with a screw.'

'I occasionally get an error message that says 'charge pressure difference is too high'.'
In that case, according to the LDA (likely referring to a diagnostic tool), the boost pressure increases to over 1.2 bar.

I also suspect that the wastegate valve might not be working correctly anymore, considering that everything is still original (306,000 km).

As soon as I enter the full load range, I experience boost pressure oscillation.

Best regards,
Michael

PS: Another log file can be found at www.mhernach.com/tdi/log1.xls.