New TDI Owner

[ThatTDILife]

Recently I purchased a 97 Jetta TDI, its got 300k miles on it and I think it needs a MAF sensor. My question is what are the mods I should persue? Its not to quick at the moment and i'm used to the power of my vr6. I know I want to straight pipe it but not sure what size. All I have done is started on a tune up.

 

[ThatTDILife]

Also, im really confused on which engine I have in my car.

 

[IndigoBlueWagon]

You car probably has engine code AHU. There are a few of an earlier engine in the car, code 1Z, but they're uncommon. And the differences between the engines in the Jetta aren't that significant unless you're rebuilding it. There should be a sticker in the trunk by the spare tire that shows the engine code, but I suspect they're not always accurate.

Regarding the low power, MAFs aren't a very common failure item in A3s. Replace the vacuum lines first, including the hose in the ECU. and you may need an N75 valve. I'd look at those first as sources of low power. Plugged catalytic converters causing low power are common, too, in high mileage cars.

The TDI isn't a VR, but it'll pull well from low revs when running properly.

 

[ThatTDILife]

You car probably has engine code AHU. There are a few of an earlier engine in the car, code 1Z, but they're uncommon. And the differences between the engines in the Jetta aren't that significant unless you're rebuilding it. There should be a sticker in the trunk by the spare tire that shows the engine code, but I suspect they're not always accurate.

Regarding the low power, MAFs aren't a very common failure item in A3s. Replace the vacuum lines first, including the hose in the ECU. and you may need an N75 valve. I'd look at those first as sources of low power. Plugged catalytic converters causing low power are common, too, in high mileage cars.

The TDI isn't a VR, but it'll pull well from low revs when running properly.

the reason I think it is the maf is because my car when you first start it has no power until you rev it up and you'll feel the power kick in almost like there is no turbo, and when your driving it after start up you have to get into it and then you'll get a sudden jolt in power and when I unplug my maf that issue goes away. still not the best power over 3k rpm

 

[IndigoBlueWagon]

That sounds more like a sticky N75 or wastegate on the turbo to me. When you unplug the MAF it just reduces power all the time. But you could try a new MAF and see what happens.

 

[ThatTDILife]

I'm going to look into the wastegate and maf aswell. also what is the deal with egr deletes, im getting mixed signals.

 

[IndigoBlueWagon]

Does your engine have an EGR cooler? 1Zs in Passats don't, but I haven't seen a TDI in a Jetta without one.

If it has a cooler you can bypass and remove the cooler, re-routing the coolant lines to and from the heater core to delete the cooler. Then you can put block-off plates on the exhaust manifold and the bottom of the EGR. The EGR valve is integrated into the intake manifold on your car so you cannot remove it. However, you can get an intake manifold from a PD130 TDI from Europe which, with a race pipe, will work on your car.

If you bypass the cooler and remove it then you'll get a CEL for EGR flow. A tune can fix that.

 

[tripl-e]

My '97 1Z Passat has an EGR cooler so at least some '97s are so equipped.

EEE

 

[IndigoBlueWagon]

Your '97 Passat is an AHU, not a 1Z.

 

[ThatTDILife]

Thanks for the info on the egr, if it stops raining i'll look for the egr cooler. I did some testing and i think both the MAF and the N75 are bad. When I unplugged the N75 it had a crap ton more power and seemed to work alot better. I ordered a manual boost controller to put in its place. Any tips on exhaust options, should I straight pipe it and if so what diameter? Thank you guys for the help so far.

 

[ThatTDILife]

I finally got around to checking my egr, I do have an egr cooler. I fitted a boost gauge today and it seems my car hits around 13 psi. I have a manual boost controller but got lost when trying to hook it up and only got results when i realized I had it hooked up to the egr thing and the brake booster so no luck with that. Also got a vag com cable in today so gonna mess around with that a bit. Also have a new maf on its way.