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Vehicle lacks power and blows black smoke?

Tiny
JEFF HERMAN
  • MEMBER
  • 2006 VOLKSWAGEN JETTA
  • 1.9L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 270,000 MILES
Upon rapid acceleration the vehicle blows black smoke until the throttle is let off. Initially the RPMs jump about 1000 so I'm assuming the turbo is working. I checked the vacuum at the pump, and it was about 30 inHg and at the turbo actuator where it was 24 inHg. I had an experienced VW mechanic listen to it and he thought it sounded like a misfire. Possibly a bad injector. I don't have a VAG-COM to aid in diagnosis. I removed the valve cover to inspect the cam and lifters and have included pictures of their condition. I was unable to remove the timing belt cover so I could rotate the cam to fully inspect the lobes and lifters but there does appear to be some wear and ridging on at least one lobe. I will inspect them more fully when I get the cover off. Then I can also adjust the clearance on the injectors. How do I know if each injector is working? It's not like I can check for a pulse since they are inside the valve cover. I'm new to this type of engine and any advice would be appreciated. The car is drivable, it just doesn't have the power it should.
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Sunday, June 11th, 2023 AT 5:18 PM

13 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,813 POSTS
Hi,

Black smoke is an indicator of a rich fuel mixture. It can be caused by a few things such as a faulty coolant temp sensor or a faulty fuel pressure regulator. Also, a bad injector can cause it. Make sure there is nothing restricting the airflow to the engine.

To test the injectors requires their removal and a test stand/pressure gauge. I attached the directions below. (Pics 1 and 2)

Also, consider checking the needle lift sensor integral on injector 3. The remaining pics below are the diagnostics for that as well.

Let me know if this helps.

Take care,

Joe

See pics below.
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Sunday, June 11th, 2023 AT 6:49 PM
Tiny
JEFF HERMAN
  • MEMBER
  • 444 POSTS
Did you look at the photos of the cam lobes? There is a coolant temperature sensor that isn't connected because the connector doesn't fit the sensor. However, the temperature gauge remains at 190 and the fans don't run but have been direct wired to a toggle switch. Lots to sort out with this car. I don't have access to any of the test equipment you described.
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Sunday, June 11th, 2023 AT 7:07 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,813 POSTS
Hi,

From the pics, the cam lobes look fine. It's really hard to tell in a picture. I hope you understand. Which pic are you seeing a disconnected temperature sensor?

Joe
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Monday, June 12th, 2023 AT 8:09 PM
Tiny
JEFF HERMAN
  • MEMBER
  • 444 POSTS
I thought they looked okay also but the camshaft/valvetrain is making a lot of noise and the engine is lacking power and misfiring. I plugged the sensor back in and it actually ran worse. I'll include a picture of the sensor which now I can't get the connector back off.
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Monday, June 12th, 2023 AT 10:10 PM
Tiny
JEFF HERMAN
  • MEMBER
  • 444 POSTS
PS: I tried to do a resistance test on the injectors and couldn't get a reading on any of them. The meter did not indicate an open circuit but gave me a reading of zero ohms?
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Monday, June 12th, 2023 AT 10:13 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,813 POSTS
I would think the resistance would be between 10 - 14 Ohms. It was 0?

Take a look at this link:

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

Let me know.

Joe
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Tuesday, June 13th, 2023 AT 7:17 PM
Tiny
JEFF HERMAN
  • MEMBER
  • 444 POSTS
This is a turbo diesel, and the injectors all have their own pump and they are located inside the valve cover. The injector loom is all internal so Noid lights and test probes and listening for clicking is impossible. When I connected my leads to the terminals on each injector, I got a zero reading. It's supposed to reading 1.80 on the 200k scale.
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Tuesday, June 13th, 2023 AT 8:45 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,813 POSTS
Hi,

If you are seeing 0, that shouldn't be. Are they all the same? It's hard to believe they all failed at the same time, but that could also explain the black smoke.

Let me know.

Joe
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Wednesday, June 14th, 2023 AT 8:37 PM
Tiny
JEFF HERMAN
  • MEMBER
  • 444 POSTS
How would it run with 4 failed injectors? I don't want to remove any to test because the rocker train uses one time torque to yield bolts.
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Thursday, June 15th, 2023 AT 7:04 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

That is a difficult question to answer because there are different degrees of failure. If they are at 0, I'm surprised it runs at all.

Let me know.

Joe
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Thursday, June 15th, 2023 AT 11:04 PM
Tiny
JEFF HERMAN
  • MEMBER
  • 444 POSTS
It runs actually very well once it shifts out of 1st and 2nd. It has trouble getting going and the valve train makes a horrendous noise. I let off the accelerator and allow it to shift into 2nd. It emits a tremendous black cloud so thick that cars behind me slow down or even switch lanes. It reminds me of an old van we drove and disconnected a vacuum line and put it in a bottle of transmission fluid. What a glorious cloud of smoke that created. People thought we blew our engine. Oh the good old days of tomfoolery. The Jetta will be parked until I replace the cam and lifters. I don't know why I'm getting a zero ohms reading. It's certainly not the first time I've checked injectors?
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Friday, June 16th, 2023 AT 5:24 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,813 POSTS
Hi,

As far as the injectors are concerned, I would have thought you would have gotten some type of reading as well. It doesn't make sense.

Let me know how things turn out after you replace the cam and lifters.

Joe
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Friday, June 16th, 2023 AT 7:46 PM
Tiny
JEFF HERMAN
  • MEMBER
  • 444 POSTS
Will do, thanks. I don't know the time frame for it. I have other projects ahead of it.
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Friday, June 16th, 2023 AT 9:16 PM

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