Any ideas about sluggishness in cooler weather??

[slpopp]

Ever since January 2006 I have been getting bouts of less than normal power.

I had the injector-glowplug-module swap done in January 2006, this is about when my less than stellar performance started. Dealer has looked at it twice, but the car will start to act normally if the weather gets really hot(above 80F here in Minnesota) and with my luck so far this has happend both times before it goes to the dealer. The car will act normal untill the weather cools off (less than 70F) for a couple of days, then it will start to become sluggish again.

The dealer has already replaced the MAF, but that did not fix the problem. When they did the injector update they forgot to reconnect the vent hose from the N75 valve to the air cleaner box. I ran the car like this for a couple of weeks before I noticed it. I had to take the car back to the dealer because I couldn't figure out where this vent hose was supposed to attach, so they know they forgot to attach the hose.

I am thinking that maybe the N75 valve injested some of our beautifull Minnesota road salt through the unatached vent hose
and is now sticking. Most of the time the car seems like it is lacking power, but there are rare occasions when the car will go like a bat-out-of-hell, kind of like when the wastegate actuator became disconnected on my 1990 Daytona Shelby (almost scarry if you don't expect it driving through downtown).

A couple of questions.....

1. Is the N75 valve either all the way on or all the way off (2 positions - on or off), or is it variable (like the water faucet in your house)? With the car idling there is vacuum on the vent hose from the N75 valve, but it is not a high flow rate (cant hear it over the noisy engine, and it takes 2 or 3 seconds before the hose will stick to my finger).

2. If I disconnect the electrical plug from the N75 valve should this shut the valve off (meaning no suction on the vent hose)?

3. If I dissconnect the electrical plug from the N75 valve will this throw a CEL code?

4. Will I be in danger of overrunning the turbo if I only have the car idling when I disconnect the N75 electrical plug?

5. Does anyone know if the N75 valve is a poppet style valve or a spool type valve?

I know these are quite a few questions but I would appreciate any answers I can get.


Added 2 minutes later - Does anyone know how to keep from being automatically logged off of the group while typing responses??

[dunno513]

Originally Posted by slpopp

Does anyone know how to keep from being automatically logged off of the group while typing responses??

Type faster

As for your other question, I do know know much about the valve other than if it get's stuck it usually causes limp mode, and will only be reset when the car is turned off, then back on. Doesn't sound like your car is going into limp, just loosing power.

TDICLUB has lots on this item.

Two things I would check being temperature dependant would be fuel filter and even though it may not make a difference on a TDI, make sure your battery terminals are clean and tight. Seen one too many problems that have been caused by this. plus if VW did work earlier, they most likely disconnected this at some point.


Vacuum hoses may be a good thing to check too. I think I saw somewhere on TDICLUB how to do an easy check for leaks.

Only other thing would be intake clogging. May want to pop off that EGR and take a peek inside it. It's condition will usually tell if the intake is of similar condition. I know it's a 2005, but anything is possible.