2004 Passat 1.9 TDi - Violent Vibration on hard acceleration, black smoke, but no loss of power?

[Randal]

I have a VW Passat 1.9 TDi 130 estate 2004 with a manual gearbox and 160k on the clock, which has developed quite a frustrating vibration problem about 3 months ago. It’s doesn’t seem to be a high pitched speed dependant vibration, but almost like a rumble or misfire. And you feel it more through the seat and the whole car chassis rather than the steering wheel.

In neutral and at a stand still, if I rev the car slowly, there is quite a noticeable vibration between about 1800 to 2400 rpm, after which it smoothes out slightly. You can feel the vibration through the car seat and the chassis and you can see the top of the engine badly vibrating.

On the road, the vibration is noticeable as you accelerate hard, particularly as the revs go through the 1800 to 2400 rpm band. Lower gears (1^st and 2^nd) are bad, but hard acceleration in the higher gears (3^rd, 4^th and 5^th) has some really violent vibration, felt through the seat and the frame. You can hear things rattling in the door pockets and the glovebox. Keep going through the rev band and it smoothes out, although you can still feel some vibration. In cruise at about 80 (on a disused airfield), the vibration is minimal.

A further few points to note are that each gear change and hard acceleration belches out a cloud of black smoke from the exhaust, and the fuel economy seems to have dropped by about 5mpg. The car also doesn’t seem to be loosing any power, and even though it violently vibrates under hard acceleration, it still seems to accelerate normally, albeit with a cloud of black smoke behind it. All indications on the dashboard are normal and no warning lights are up.

I’ve been trawling the various VW forums to try and diagnose what the problem could be. Work I’ve done thus far:

1. Checked the inner and out CV joints and they seemed ok with no play. But to be sure, I changed the complete shafts and joints over with another (non-running) Passat that drove ok when it was on the road a few weeks ago. Didn’t really make any difference to the vibration issue.

2. I changed the timing belt about 6 months ago, so I rechecked the timing in case it had slipped (causing a misfire?). All the locking tools went straight on and nothing had moved, so timing is ok.

3. I thought the black smoke might indicate a fuel problem, and someone suggested a clogged fuel filter may cause vibrations through rough running. So I’ve changed that and also put some pretty robust injector cleaner in the fuel tank to clean everything. Didn’t cure the problem.

4. Wheel bearings are ok. Swapped the wheels around and checked all the suspension joints. Didn’t make and difference.

5. Put VCDS Lite on it and no codes came up for the engine, but a code came up for fuel that said ‘00476 Control Module for Fuel Pump (J538)’ which isn’t showing up on the Ross-Tech site. However, when I turn the ignition on, I can hear the fuel pump running ok.

6. Another thing that I noted today is that the left hand (from driver’s seat) front engine mount appears to be slightly leaking. Right hand one and gearbox ones appear to be ok.

So the question is, anyone any thoughts on what could be causing the vibration issue? Would a failed engine mount cause such violent vibration during acceleration, and only across a certain rpm range? Could it be a failing DMF? Injectors causing rough running? Anything else?

Greatly appreciate any advice.

[caldirun]

Head wiring loom been changed? if not change it.

[Randal]

Head wiring loom been changed? if not change it.

Thanks for the suggestion. I've now managed to change the head loom (I presume that you mean the injector loom that comes through the back of the head?). Took it for a drive and I've still got the same issues with the vibration on acceleration and the black smoke.

You can still see the engine badly vibrating in that 1800 to 2400 rpm band when you’re parked up, and then feel it through the whole car when you are accelerating through that rpm band.

Something is definitely wrong and I’m running out of ideas. Anyone got any further suggestions at what could be causing this issue?

[caldirun]

The fault code does not make sense, module for fuel pump would be redundant as PD uses the injectors as a pump, the pump you can hear is only
the lift pump in the tank, this supplies the tandem pump (also low pressure) which is just a dumb pump driven off the camshaft.
I would suspect a failed DMF and vacuum leaks/turbo boost leaks for the smoke and vibration.

[Randal]

The fault code does not make sense, module for fuel pump would be redundant as PD uses the injectors as a pump, the pump you can hear is only
the lift pump in the tank, this supplies the tandem pump (also low pressure) which is just a dumb pump driven off the camshaft.
I would suspect a failed DMF and vacuum leaks/turbo boost leaks for the smoke and vibration.

Thanks for your help thus far and it is much appreciated. The code came from a version of VCDS-Lite that came with the cable that I got off of eBay. So I’m presuming that it is a legit copy.

I’ve trawled the internet about DMF failing symptoms and most seem to point towards a judder on clutch initial bite, chattering sound, difficulty in engaging gear etc. But I don’t seem to have any of those. The car always starts first time and runs sweet on idle, and you can engage every gear easily, with no judder or difficulty when you release the clutch, no matter how slow you do it.

One thing is that I occasionally get a rattling sound from under the car which sounds like a loose U clamp on the exhaust rattling around or a loose shield somewhere. I can’t seem to find it yet, and I know that some say a DMF failure sounds like pebbles in a washing machine.

So I put the front end up on axle stands and ran the engine in every gear with the ESP off (otherwise it wouldn’t fully rev). Got underneath the car with someone else changing the gears and couldn’t hear anything from the gearbox region where the DMF would be. Still couldn’t find the rattle either.

Interestingly, with the car running on the axle stands, I noted that the car still did the bad vibration thing around the 2000 rpm mark, although it didn’t seem to do it as bad as when out on the road, when I suppose it would be under more load.

Ref the vacuum leaks/turbo boost leak suggestion, I haven’t found anything yet. I’ve had various angled mirrors all around and especially down the turbo side, and there doesn’t appear to be anything noticeable. Could a leak be causing both the vibration and black smoke issue?

[Randal]

Just to close this off if it helps anyone in the future.

I took the car to a local garage to try and get their opinion and they initially thought it was either a bad injector or a failing DMF. They plugged their computer to the car and the injectors seemed to be working ok, so they were positive it was the DMF, but when they got under the car, they couldn’t hear anything.

So I took it to a second garage who also specialised in VWs, and he thought it was being caused by a misfire. Plugged his computer in and no issues were found. But he then took off the rocker cover to look at the camshaft and noticed that it was shot, with 2 of the cams virtually round through wear, and 2 of the followers also worn through.

So we had the camshaft, followers and shells changed and now it is running like a new car. Camshafts on these 130s seem to be a bit of an issue apparently.