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How do I disable the injectors to run a compression test?

Tiny
JEFF HERMAN
  • MEMBER
  • 2007 VOLKSWAGEN JETTA
  • 1.9L
  • 4 CYL
  • TURBO
  • 2WD
  • AUTOMATIC
  • 271,000 MILES
I need to run a compression test on the car listed above TDI with a four cylinder, not sure what size, can't find it on door jamb or under hood. Do I have to access the fuel pump relay and unplug it?
Wednesday, September 14th, 2022 AT 6:17 PM

10 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

I would be happy to help, but there is no Jetta TDI for model years 2007 through 2008. By chance, could it be a different model year? They made them in 2006 and 2009.

See pic 1 below for engine options during the 2007 model year.

If you look at the remaining pictures, they provide the procedure for a compression test on a 2006 1.9L TDI Jetta. The last pic attached provides the manufacturer's specs.

Let me know if this helps or if I have the wrong model year.

Take care,

Joe
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Wednesday, September 14th, 2022 AT 8:08 PM
Tiny
JEFF HERMAN
  • MEMBER
  • 449 POSTS
I only said 2007 because the manufacture date is 10/06. Before I proceed, I have to identify which glow plugs are in it. If they are the 7V Bosch they were recalled. If they are 5V or 7V NGK I will attempt to remove them and pray the tips don't stay in the head. The car runs fine, maybe a little valve noise. I'm not sure because I don't know enough about diesels. It whiffs a little black smoke while driving. I wanted to check compression before I buy it, but it seems like a pain. Here is a video of it idling and revving. Let me know what you think. I've had it up to 85 and its smooth. All transmission modes work and seems to shift fine. Video option doesn't seem to work but I'll try and send it.
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Wednesday, September 14th, 2022 AT 9:15 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

If it is idling properly, has good power, and there is no misfiring, chances are the compression is okay. The black smoke is normally the result of too much fuel getting into the combustion chamber.

As far as the video is concerned, it didn't upload. Let me know if you can try again.

Take care,

Joe
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Thursday, September 15th, 2022 AT 5:59 PM
Tiny
JEFF HERMAN
  • MEMBER
  • 449 POSTS
It idles fine, isn't all that powerful but seems to reach 0-60 in the specified time, about 9 seconds. The turbo isn't really felt that much. I'm sure it will hit 100 but not the 128 in the specs. I am sure things are not maintained as should me and need cleaning, intercooler, vanes in turbo, intake, etc. Which I will take care of when I bring it home. I'm going to trust my gut on this one and buy it. I am told I can turn up the boost. First I will just do all the maintenance that should have been done and see where we are at. Thanks for your help.
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Thursday, September 15th, 2022 AT 9:08 PM
Tiny
JEFF HERMAN
  • MEMBER
  • 449 POSTS
New question. Will a standard OBDII scanner work on this vehicle or do I need a VCDS?
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Thursday, September 15th, 2022 AT 9:43 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

That is based on the scan tool used. Some have the capabilities and others don't. I would suggest getting your hands on a basic VAG scan tool. You can get them online at good prices. I know Amazon has them.

The best thing to do is just try the scanner you have. Hopefully, it will work.

Let me know how things turn out for you.

Take care,

Joe
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Friday, September 16th, 2022 AT 8:12 PM
Tiny
JEFF HERMAN
  • MEMBER
  • 449 POSTS
I've been looking for the OBDII port and can't find it?
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Friday, September 16th, 2022 AT 10:24 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

The DLC is located under a cover on the driver's side footwell. Sometimes I think they try to hide them. LOL

Let me know if you find it.

Joe
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Saturday, September 17th, 2022 AT 9:24 PM
Tiny
JEFF HERMAN
  • MEMBER
  • 449 POSTS
New problem. I went to start the car and the battery was drained, so I charged it and now there is no crank at all. Dash lights come on and what looks like a little red wrench flashes and there is a beep. No indication of crank at all. Silence. Is it the immobilizer system? I read after a battery change it needs to be reset. Scratching my head on all this anti-theft stuff. Lol
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Thursday, September 29th, 2022 AT 5:52 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi Jeff, I have a favor to ask. Is it possible for you to start a new post? We try to keep the threads specific to one topic, so they are more helpful to others.

Here is the link to start a new post:

https://www.2carpros.com/questions/new

Just copy and paste your question.

I hope you understand.

Take care,

Joe
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Thursday, September 29th, 2022 AT 7:52 PM

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