1.9 TDI BPX Turbo Problems & Solutions

Hi, I've been having problems with my Ibiza for quite some time now, specifically with its turbo boost pressure. I have a boost gauge from Raid installed, which has been tested multiple times and is working correctly. The measurement point is located after the EGR valve, as you can see in the picture.

Here's the problem: When starting the engine, everything seems fine; the boost pressure gauge shows a value of 0.0. After driving for a short distance, everything is still okay; the turbocharger works as it should, and there is boost pressure. However, every time I drive over a bump or pothole, the boost pressure drops. The LDA (boost pressure sensor) then displays negative values (-0.2 to -1.0 bar) at idle, which shouldn't be within the normal boost range. The driving behavior is worse, with reduced acceleration. During continued driving, the condition fluctuates between better and worse.

My first question is how it's even possible for the LDA to produce such values.

I've checked the entire intercooler piping as best I could for cracks or loose clamps, but unfortunately, I didn't find anything. The intercooler was replaced 1000 km ago, and the turbo was replaced 10,000 km ago.

Has anyone encountered this problem before and can help me narrow down the search? Could it be related to the charge air system, vacuum lines, EGR valve, or vacuum pump?

Best regards,
LG Reodux

Hi,

As you have surely read in the terms of service ( ), for PCI, Auto-Intern, and DRV customers, a vehicle diagnostic support key is necessary to provide helpful information for diesel mechanics regarding diagnostics.
You can also obtain the Diesel Mechanic License, which also includes KDataScope and KPower.

From then on, feel free to continue the discussion here.

Best regards, Rainer.