Stuttering while cruising

Jpontiac68 · Nov 16, 2017

Hello fellow tdi club enthusiast

As stated in the title I have an issue while cruising around 1800 to 2000 Rpm, I'm wondering if you guys can help me determine what the problem might be. Also another thing to note, it seems to do it while its is closer to 150F and full temp being 190F. I'm wondering if it could be fuel related as when priming the pump via turning the ignition I don't hear any noise coming from the fuel pump as if it seems it isn't priming. I will do a code check on the car to see what is up?

BobnOH · Nov 16, 2017

You won't hear a noise for fuel, that's on the newer models with in tank pump.
You should have a section of clear hose in the fuel lines on top. A giant air bubble can indicate air in there. Check the little fuel returns off the injectors are old and damaged. Also check air supply, filter, piping.

UhOh · Nov 16, 2017

What's your IQ set at? Any recent changes to engine stuff?

Jpontiac68 · Nov 16, 2017

My IQ should be the same from the picture linked here:http://pics.tdiclub.com
But over the course of a year I don't know what it could be at now

Jpontiac68 · Nov 16, 2017

Anyone think it could be turbo related peak boost is 22psi at highest and sustained is 17 to 18psi do these seem too high btw it has a stage 1 tune

UhOh · Nov 16, 2017

I was meaning IQ (Injected Quantity), rather than timing. Low IQ is notorious for producing shuddering.

If it's purely based on boost then I'd think that you should be able to attain the same boost levels in a higher RPM, and if it ain't occurring at higher RPMs then it's questionable whether it's turbo related.

wonneber · Nov 17, 2017

I sprayed my boost lines with soapy water to find a leak.
Look for oily residue also.

Jpontiac68 · Nov 18, 2017

How high of rpm should I be testing for turbo issues? And what boost lines should I look for leaks?

UhOh · Nov 18, 2017

I think we're getting ahead of ourselves here. From your original post I don't get the impression that boost is even a concern. Perhaps rewind and get a betting understanding of what you're experiencing.

1,800 - 2,000 rpm you get this "stutter." Any chance this could be a "shudder?" What are you doing with the accelerator when this happens?

Again, the picture that I looked at was timing (which, if I recall correctly, was OK), I'd like to know what your IQ is.

What's been done to the car since it last did not exhibit this behavior? How long ago was that?

wonneber · Nov 19, 2017

Jpontiac68 said:
How high of rpm should I be testing for turbo issues? And what boost lines should I look for leaks?

I checked at idle.
Check from the turbo, through the intercooler, to the EGR valve.
All connections as well.
Check test, fairly easy.

TDIFan1989 · Nov 19, 2017

Is the shudder/studder related strictly to RPMs if the vehicle is stopped or are you getting this when your vehicle is running at top speed?

UhOh · Nov 19, 2017

Documentation on performance testing, which is what would be used to evaluate boost function, can be found at Malone's website: PDF; tests, with the exception of capturing atmospheric pressure, are done in third gear between 1,500 rpm and redline (all-out stomping on it).

Jpontiac68 · Nov 21, 2017

TDIFan1989 said:
Is the shudder/studder related strictly to RPMs if the vehicle is stopped or are you getting this when your vehicle is running at top speed?

I am getting it when around 1800 to 2000 Rpm at idle it is fine and at top speed for the most part

Jpontiac68 · Nov 21, 2017

Also one note is I put a fuel cleaner in the tank and immediately it started making the problem less pronounced, and after 20 miles or so it started to come back once again.

UhOh · Nov 21, 2017

Jpontiac68 said:
Also one note is I put a fuel cleaner in the tank and immediately it started making the problem less pronounced, and after 20 miles or so it started to come back once again.

What "cleaner?"

Might be worth doing a Diesel Purge.

When was the fuel filter last changed? Are you seeing bubbles in the clear fuel line?

Again, what is your IQ?

TDIFan1989 · Nov 21, 2017

Jpontiac68 said:
I am getting it when around 1800 to 2000 Rpm at idle it is fine and at top speed for the most part

When you are in neutral and rev to the 1800-2000 RPM, does the engine shudder then?

If you don't get the shudder while revving in neutral, your issue could be drive train related or more likely that your tires have either lost balance or broken a belt.

UhOh · Nov 21, 2017

One reason why I was attracted to this thread was because my wife's car also shudders between 1,800 and 2,000 rpm. Her car does this under a big load, in 5ith gear- I smash the accelerator and it'll shudder a bit and then settle down. I have two possible reasons for this: 1) IQ (I'm getting, of late, some slow-down shudder, which is wholly in line with a low IQ); or, 2) Bad inner CV joint (I'd disconnected axles when doing the clutch and this "might" have contributed, though the joints seemed to be OK).

Jpontiac68 · Nov 21, 2017

The fuel filter was changed I believe at 80k miles and the car has now 110k on it, the cleaner put in was an in tank additive to clean the fuel system. As to the question of my IQ I'm still unsure I will have to see if I can get it checked soon. And if the IQ was spot on in the past how would the number change? That's one thing I'm confused on

Jpontiac68 · Nov 21, 2017

TDIFan1989 said:
When you are in neutral and rev to the 1800-2000 RPM, does the engine shudder then?

If you don't get the shudder while revving in neutral, your issue could be drive train related or more likely that your tires have either lost balance or broken a belt.

No it doesn't do it while revving but why wouldn't it happen at all rpm ranges even while driving, if it was drivetrain related?

Jpontiac68 · Nov 21, 2017

UhOh said:
One reason why I was attracted to this thread was because my wife's car also shudders between 1,800 and 2,000 rpm. Her car does this under a big load, in 5ith gear- I smash the accelerator and it'll shudder a bit and then settle down. I have two possible reasons for this: 1) IQ (I'm getting, of late, some slow-down shudder, which is wholly in line with a low IQ); or, 2) Bad inner CV joint (I'd disconnected axles when doing the clutch and this "might" have contributed, though the joints seemed to be OK).

The same thing happened to me did a clutch and flywheel job and forgot to tighten one of the triple square c.f. joint bolts so maybe that could be at fault

UhOh · Nov 21, 2017

Jpontiac68 said:
The fuel filter was changed I believe at 80k miles and the car has now 110k on it, the cleaner put in was an in tank additive to clean the fuel system. As to the question of my IQ I'm still unsure I will have to see if I can get it checked soon. And if the IQ was spot on in the past how would the number change? That's one thing I'm confused on

We're guessing all over the place here.

I asked what cleaner and you respond with the same answer as before (which prompted my question in the first place).

Things change. If they didn't then none us would be here. Basic troubleshooting OR chase your tail.

If you have a standard fuel filter with 30k miles on it I'd certainly be looking to change it. 20k miles is the service interval. Start making some necessary changes if you want to make a change to your car.

TDIFan1989 · Nov 21, 2017

Speaking on prior experience, I had a belt from a tire lose integrity. The vehicle would shake violently going over 80 kph (50 mph). Also, I had a steering bearing go on my car before as well, that exhibited as a studdering especially when I was in high gear or braking. The fact that you don't hear the studder under a no-load senario (revving the engine) is odd.

TDIFan1989 · Nov 21, 2017

At this point, find yourself a tech/shop with a dyno and let them have a crack at it.

indysoto · Nov 25, 2017

1,800 and 2,000 rpm in 5th gear generally is called lugging and you should be in 4th, put's alot of pressure on the turbo and is bad for it. Could be combined with a plugged fuel filter and or air filter / dirty maf?

Jpontiac68 · Nov 26, 2017

I just scanned it today and got a P1354 modulating piston displacement sensor, looks like a potential injection pump sensor issue. Gonna get it checked out, anyone have any advice or more information in the mean time? Thanks guys

Jpontiac68 · Nov 26, 2017

Just scanned the codes and got a P1354 modulating piston displacement sensor, looks like a potential injection pump sensor issue, going to get it checked out Monday, any information or advice in the mean time?

TDIFan1989 · Nov 28, 2017

Jpontiac68 said:
Just scanned the codes and got a P1354 modulating piston displacement sensor, looks like a potential injection pump sensor issue, going to get it checked out Monday, any information or advice in the mean time?

At this point, let the shop do their diagnostics/replacement of the part. This was all that was available from online references:
https://www.autocodes.com/p1354_volkswagen.html

If anything, this fault code will give some clarity on if your injectors are bad or the sensor is gone.

Stuttering while cruising

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