98 Jetta TDI low power jssue

Discussion in 'VW Mk3 Jetta, Passat TDI and other/older diesels' started by Josh329, Jan 8, 2017.

  1. Josh329

    Josh329 New Member

    Joined:
    Jan 8, 2017
    Messages:
    6
    Car:
    1998, Volkswagen, Jetta TDI
    Location:
    Wilkes-Barre, PA
    Please delete and redirect me to a thread if this question has already been answered!

    Hello everyone, I'm new to the Volkswagen world and semi new to diesels...Just bought a 98 Jetta TDI with around 200k on it..having an issue with power.

    If driven like grandpa on a Sunday afternoon there's no issues. The moment I drive slightly harder such as accelerating onto a highway, whether in 3rd, 4th, or 5th gear and using more throttle, I can feel the power just drop off. I then have to hold it to the floor to maintain speed on small inclines. Restart and problem gone till I accelerate again. No smoke either. No dash lights. Completely stock, no mods. Oil changed and fuel filter. Even ran seafoam through oil before changing and fuel for about a week.

    No sure if related, but there is a tiny coolant leak coming from thermostat housing and the pipe going from heater core to oil cooler (No longer available for purchase). The speedo and temp gauges don't work either. Working on those soon also.
     
    login to remove this ad
  2. Seatman

    Seatman Well-Known Member

    Joined:
    Jul 9, 2010
    Messages:
    5,778
    Car:
    2000 Mk4 Golf Estate 1.9tdi 174 bhp
    Location:
    Scotland
    Mods:
    PP764's, turbo and mapping
    It's quite possibly turbo related, maybe a bad vac pipe or waste gate actuator or even a stuck waste gate.
    Your turbo works on pressure so the wastegate should operate with pressure applied.
    There's also a small pipe in the ecu that can need replaced.
    More info in the diy index
     
    Josh329 likes this.
  3. Josh329

    Josh329 New Member

    Joined:
    Jan 8, 2017
    Messages:
    6
    Car:
    1998, Volkswagen, Jetta TDI
    Location:
    Wilkes-Barre, PA
    Ok thanks, I'll look in to those. One of the first things I'd like to do is get a boost gauge installed so I can monitor the turbo. Think I'll do that first so I have a heading.

    Sent from my XT1585 using Tapatalk
     
  4. audi1z

    audi1z Member

    Joined:
    Oct 16, 2010
    Messages:
    377
    Car:
    Audi 80 1Z Engine
    Spend the money for a VCDS w/ adapter. You can e.g. read the fault codes, and monitor the relevant engine parameters including charge pressure.
    Having a boost gauge will only tell you what the actual charge pressure is, but not why. And I am very sure that your engine goes into limp mode, which means reduced charge pressure too.
    Cheers
     
    Josh329 likes this.
  5. Josh329

    Josh329 New Member

    Joined:
    Jan 8, 2017
    Messages:
    6
    Car:
    1998, Volkswagen, Jetta TDI
    Location:
    Wilkes-Barre, PA
    Thanks, I'll look into it

    Sent from my XT1585 using Tapatalk
     
  6. Eric Delling

    Eric Delling New Member

    Joined:
    Jan 10, 2017
    Messages:
    6
    Car:
    2005 Passat TDI
    Location:
    Sacramento
    What do you mean?

    I would start by going through the whole EGR system and also verify the the vac lines that monitor turbo pressure are not clogged / broken.
     
  7. ak77

    ak77 Member

    Joined:
    May 5, 2014
    Messages:
    80
    Car:
    Mk5 GT Tdi Golf
    Location:
    Perth WA
    I would start with EgR cooler as this is the endemic issue with most particulate diesel cars and specially in VW models with 149K on clock. Next look at the front of engine is the butterfly intake manifold is opening and closing , this might be choking the engine if it's left in open position due to too many gasses and your sensors will go crazy. Best hook it up onto VCDS and get a reading . Also try as a test , block of your EGR pop to engine and see if you get highly Mpgs , and better response from engine and ECU. You could have electrical intermittent error affecting your system. Run VCDS.
    Cheers


    Sent from my iPhone using Tapatalk
     
  8. ak77

    ak77 Member

    Joined:
    May 5, 2014
    Messages:
    80
    Car:
    Mk5 GT Tdi Golf
    Location:
    Perth WA
    Also it could be a particulate filter that is blocked and can't send all the gasses to burn.


    Sent from my iPhone using Tapatalk
     
  9. Josh329

    Josh329 New Member

    Joined:
    Jan 8, 2017
    Messages:
    6
    Car:
    1998, Volkswagen, Jetta TDI
    Location:
    Wilkes-Barre, PA
    Eric, this is the pipe i mentioned in the beginning of the post, [​IMG]. This is where my coolant leak was. Comes from the expansion tank, to the water pump and heater core. At first it appeared to be the oil cooler. But I ended up having to fix it this past weekend. Had a few small holes in it. This pipe has been discontinued and the nearest one to me was in Maryland for $100 plus shipping. No way was i spending more than $50. So I manufactured one with thick rubber hose and fittings and clamps. All good. No longer leaking. I do still have a few small issues I'm slowly addressing. Such as I'm going to be replacing all of my vac lines including the one going to my ECU considering I'm getting the 65535 engine code. Also need a new instrument cluster cause my speedo, temp, mileage, and possibly a few lights aren't working. Including the engine light cause i do have a code for that as well. Unless perhaps it's just a burnt bulb but haven't gotten that far. I also plan to do a egr delete and full cleaning of the intake manifold. Massive amounts of build up in there. But I'm pretty sure one of my main reasons for limp mode is the vac line running to the ECU. Also, i use an updated snap-on computer for my info right now..I did find a Bluetooth adapter that works with the torque app and fully connects to the car to give me all sorts of info, just like the snap-on and vag does. Just less money lol. I appreciate all the help fellas! These forums have really helped me the past couple weeks! Thanks everyone.

    Sent from my XT1585 using Tapatalk
     

Share This Page