N75 / Boost Pressure Regulator Location

Rince

Rince

Member
Hey guys,

I am going to have a look and see if I can find out what is causing this limp mode problem after I get to 70mph later and it seems the biggest culprits are the N75 / Boost Pressure Regulator and the MAF.

The MAF I can see easily (and will clean it) but where should I be looking for pipes that can cause this? Are there any photos that anyone can share at all to show me where I need to be checking?

Cheers,

Andy
 
Hi Andy,

The N75 valve on your 2002 TDI75 is easy to access. As you stand looking into the engine bay, you'll see the coolant expansion tank on the right. Just to the left behind the expansion tank, at the very back of the engine bay, there are a variety of untidy looking things surrounded in thin vacuum/pressure hoses, wires and bracketry. One of those little gizmos is the N75 (though I can't remember which one without having a look). On most 2002 TDI 75s, the hose that connects the N75's pressure output to the turbo's wastegate actuator is green. This should help you to identify the N75 valve and the hose that's most likely to be the culprit. Checking these tubes is easy at the N75 end, but access to the turbo end isn't easy on a driveway.

On the compressor side of the turbo, you should see three thin hoses. As mentioned, the green one connects to the wastegate actuator. The thinner black one connects to the compressor housing and the thicker black one connects to the top of the intake pipe, just prior to the compressor wheel.

Hope this helps,

Tom
 
That is great thanks Tom.

So is it adviseable to get it on a ramp tho check everything properly?

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Sat in the waiting room at the local garage while they see if they can find the source of the fault. On a ramp as we speak.

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Excellent post Timmus - on LHD cars it's on t'other side of course. Worth replacing the small hoses as well.
 
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