Vehicle lacks power and blows black smoke?

2006 VOLKSWAGEN JETTA

270,000 MILES • 1.9L • 4 CYL • 2WD • AUTOMATIC

JEFF HERMAN

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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.

Images (Click to enlarge)

Jun 11, 2023 at 5:18 PM

JACOBANDNICKOLAS

CERTIFIED EXPERT
110,175 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.

Images (Click to enlarge)

Jun 11, 2023 at 6:49 PM

JEFF HERMAN

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486 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.

Jun 11, 2023 at 7:07 PM

JACOBANDNICKOLAS

CERTIFIED EXPERT
110,175 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

Jun 12, 2023 at 8:09 PM

JEFF HERMAN

MEMBER
486 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.

Image (Click to enlarge)

Jun 12, 2023 at 10:10 PM

JEFF HERMAN

MEMBER
486 POSTS

I thought they looked OK 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.

Jun 12, 2023 at 10:10 PM

JEFF HERMAN

MEMBER
486 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?

Jun 12, 2023 at 10:13 PM

JACOBANDNICKOLAS

CERTIFIED EXPERT
110,175 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

Jun 13, 2023 at 7:17 PM

JEFF HERMAN

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486 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.

Jun 13, 2023 at 8:45 PM

JACOBANDNICKOLAS

CERTIFIED EXPERT
110,175 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

Jun 14, 2023 at 8:37 PM

JEFF HERMAN

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486 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.

Jun 15, 2023 at 7:04 AM

JACOBANDNICKOLAS

CERTIFIED EXPERT
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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

Jun 15, 2023 at 11:04 PM

JEFF HERMAN

MEMBER
486 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?

Jun 16, 2023 at 5:24 AM

JACOBANDNICKOLAS

CERTIFIED EXPERT
110,175 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

Jun 16, 2023 at 7:46 PM

JEFF HERMAN

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486 POSTS

Will do, thanks. I don't know the time frame for it. I have other projects ahead of it.

Jun 16, 2023 at 9:16 PM