Engine Vibration after Timing Belt Change & Colt Stage 2 Camshaft Installation

You need to do a scan of the injector balance with VCDS among other things.
If that looks OK then I might look at the flywheel situation.
Is your flywheel/clutch the original that came with the car?
How many miles are on the injectors? Are they originals?
How was the timing set when the timing belt was done?

rocketeer928 said:

A few years ago, I changed out the engine mounts, so I don't think the vibration would be because of worn mounts.

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Sometimes things eventually fail at the most inopportune moments. The engine motor mount gets messed with when you do the TB: double-check your work here.

Do you get any vibrations just sitting at idle?

How sure are you that it isn't just the fact that you put in a stage 2 cam?
Since you changed your TB have you put everything at TDC and check to make sure that nothing moved?

I'm 20 minutes down the road from colt cams and we've never had a problem with their products. Mark's got one in a 96 golf and it doesn't rattle that much, only difference I noticed with it installed was lower EGTs and less smoke.

It is well over a 5 degree increase in duration though. They also make a stage 1 cam, which has the lift of stage 2 but with essentially stock duration.

MAF, Electrical Grounds

Not sure if my experience might help, but when I changed the camshaft out on an 04' Jetta with 227k miles, I installed an upgraded Frank6 camshaft and did the timing belt as well. Afterwards, the car had a bad idle and poor performance which turned out to be a result of poor electrical grounds and the wrong MAF. I addressed all those issues and the car runs 10x better. The car is a 5 speed and has a Malone stage 1 tune. The gasser MAF caused all kinds of problems..not good on this car.

Your injector deviation shouldn't be any cause for concern, the numbers are fine. (I don't recall ever hearing anyone with bent rods complain about vibrations- mostly).

When you say that you're getting vibration while driving is there any difference between accelerating and decelerating? That is, can you tell whether this the vibration is more prone from torque?

What's the state of the dogbone mount?

Maybe pop off the serpentine belt and see if that does anything. Might want to peek at the crank pulley while you're there.

I think that you're probably going to have to break out a/the stethoscope.

rocketeer928 said:

That's my question. I'm wondering if anyone has experienced similar vibration by installing the Colt Stage 2 camshaft, as that's the only difference since June.

This is the second time I've changed the timing belt on my car, so I have the experience, and I know everything was at TDC.

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It's not uncommon to have a little vibration with a throaty cam. But with a stage2 it shouldn't be all that much. Your iq in group 6 might be worth looking at. When my iq was 8.5-9 my car ran rough. Now that it's 5 it's really smooth.

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IQ deviation pretty much showed that your compression numbers, at least relative, would be OK.

Again, pop off your serp belt and see if there's any change. Things in the middle of your engine seem fine, things at the ends need to be vetted. If you've got an alternator clutch or serp belt pulley/tensioner that's crapping out then that could cause some pulsing, some vibrations. Maybe the cam, while being perfectly fine, is helping exasperate something else.

Oh, yeah!, though I don't believe it's an issue in your case, I had an out of balance cooling fan (broken outer fan blade edge) that would cause the entire car to shake! Took me a while to track this down: got the car during cooler weather and didn't experience anything until the weather started warming up- it would happen only intermittently as the car needed to run the extra fan to cool the engine. I haven't experienced a failing DMF but from what I've read this could readily have passed as a failing DMF. My point here is that sometimes there's a pretty big misdirection going on and the source of the issue is "over there."

I'll now go away.

I put a Colt stage 2 in the ALH about a year ago and along with timing belt kit and a bunch of other items to help it breathe.

The engine is very smooth at idle and at all RPM's. I was expecting a lumpier experience but it has been fine. Actually, it is really hard to notice this cam compared to stock.

My IQ is about the same as yours at ~4, I think the readings I got for my injectors looked like the ones you posted. It has been a while but that looks very familiar.

It's sort of strange that you are getting a vibration at idle. I was thinking that it could be something in the driveshaft area or brakes dragging to explain the 45 to 50 mph issues.

Now looking like a shift toward the rear of the engine is in order. (not sure why the impulse to mess with the injectors) BUT...

Do ALHs ever have issues with their harmonic dampners?

Oilhammer, are you out there?

Rocketeer, any update on your vibration issue?

I just finished a similar rebuild and am having increased vibration, most pronounced at idle and lower rpm.

How often are you at 1400 rpm? that is too low to be spending much time cruising in in an ALH. you are effectively lugging the engine at that point and VNTs do not like lugging.

is the vibration something you notice as you pass 1400 rpm in like first or second gear? if so its possible that you are just hitting a harmonic vibration of the car or even the exhaust piping itself with your mods, newer motor and dogbone mounts.

with all of those mods I doubt you spend much time driving around like there is an egg under the go pedal. if you are spending a lot of time cruising at 1400 rpm, may I suggest downshifting to raise the RPMS?

I know you know your car very well, and it is probably one of the best put together Stage5 cars in the country, but with so many not stock variables in there you may be chasing your tail for a long time trying to hunt down something that may just be a quirk of your whole package.

rocketeer928 said:

Still working on it. Really annoying around 1400 rpm

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Does your vibration also happen in neutral or only when driving?

If I read your posts correctly.....you installed "a new VR6 driver's side axle" at the same time as the new cam, which is when the vibration started.

I would suspect the new axle as the cause of the vibration before I would suspect the cam.
Where did you get the new axle from?
I would put another known good axle in to see if the vibration is still there.

Are you still waiting on your new nozzles and injector work?

That means that the nozzles/injectors that were in there weren't causing this problem?

Crank shaft position sensor a bit wonky? (sorry if this has already been addressed)

rocketeer928 said:

So now I'm convinced that the vibration is due to the new dogbone, and I'll just have to live with it as the dogbone naturally wears. Just a few years ago I had changed out the original engine and transmission mounts for new OEM mounts.
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Silly question.
Wouldn't it have been easier, faster, and cheaper to install the original dogbone for testing?
New bone if you didn't save the old one.

I do admit I've done similar for testing but not at the level you did.