Help needed! Vibration under load. No CEL

Baloo2u

New member
Joined
May 2, 2021
Location
New York STATE
TDI
2015 Q7 TDI 2013 Passat TDI SEL
Quick background. I’ve been a field service engineer for nearly 20 years, been working on VWs for probably close to 30+. Please think if your solution is plausible before posting.

Purchased a 2013 Passat TDI SEL in Portland Oregon with about 106K on the clock. When wee arrived the engine was warm to the touch, not hot like it was just driven, but warm. It has brand new Continental tires, It seemed to drive fine and accelerate well, no issues seen or felt so we purchased it. We then began the drive back to New York. It ran great all day although I felt a slight vibration which seemed to be under load. We also thought it might be a tire vibration. But it still pulled flawlessly and no CELs.

We made it to Spokane Washington that night. The next morning, the car started easily, but seemed to buck and misfire when cold but once warmed up again ran flawlessly. No CEL. We got some Lucas injector cleaner and ran it through thinking it might be a dirty or partially clogged injector. Again the car ran flawlessly all day crossing Idaho and Montana and into Wyoming. It never misfired again.

The next morning, expecting the stumble, we let it warm up a bit, but it was still a bit hesitant. It ran well all day across South Dakota. When we turned onto 29 towards Souix City Iowa, we felt a hard misfire at the speed limit of 80. We immediately left off the gas but it was now running smooth.

We pulled over, removed the engine cover, and found that there was a repair to one of the injector electrical connectors, done by VW. Damn mice! How do I know. It was yellow. That’s what they use. The car would idle fine, no other symptoms other than the misfire under load and the slight vibration under load. Still no CEL.

We found a local dealer in Souix City and made that our destination, found a hotel half a mile from the dealer and limped it there.

Once stopped, we smelled coolant. It looks like it blew the water pump. Still no CEL!

We limped it to the dealer and had it scanned. Scan results attached.https://photos.app.goo.gl/jMPSpL7nEpZTpL1S9

So, What could cause a vibration under load, cause the engine to stumble in the morning and a misfire at speed without throwing a CEL?
How could this potentially cause the water pump to fail?
 
Last edited:

pedroYUL

Veteran Member
Joined
Sep 8, 2011
Location
MI, USA
TDI
2004 Jetta wagon BEW; 2015 Passat SE CVCA; 2015 GSW CRUA
Sounds like injector balance issue
 

pedroYUL

Veteran Member
Joined
Sep 8, 2011
Location
MI, USA
TDI
2004 Jetta wagon BEW; 2015 Passat SE CVCA; 2015 GSW CRUA
There:

 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis (where it's safe)
TDI
There are just too many to list....
Replace the fuel filter and reset the injector values. It will probably fix it.

Lots of these cars have water pump failures from sitting. Seems the internal seal sticks to the impeller shaft, and once the engine is used again they start to fail shortly thereafter.
 
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