rough idle- sometimes

[mopractice]

Hi,

My 2004 sometimes has an uneven idle - not vibration. The engine will skip a beat and then flutter until I add a few rpms. It does this about 10% of the time when I come to a stop sign - the rest of the stops are perfectly normal

Car is chain less, has new fuel filter, cam and lifters are good, intake cleaned about 20,000 miles ago, EGR cleaned the last time I changed oil.

There is no CEL, I have vag com but have not hooked it up yet. When I connect it, what should I be looking for? Any suggestions?

MIKE

 

[abctdi]

I'll bet you've never replaced your spark plugs...
Free bump nontheless.

 

[volkswagendude]

I'll bet you've never replaced your spark plugs...
Free bump nontheless.

No silly..his ignition cables! Ya, you know. The ones nearest the turbo, and prone to heat cracking the rubber covering.

Free bump.

 

[dualcitizen]

Mike,

I don't know the answer, but I have an 04 and have experienced a little of the same recently.

 

[oilhammer]

Check the timing...it is called 'torsion' or something in VCDS (depending on version). You want it basically as close to "0" as you can get it. If the timing belt was not put on and tensioned just so, it can be off. Your elongated holes in the cam sprocket should be about centered on the bolts, just like when it left the factory.

 

[Aron]

Rough Idle

I have been experiencing the idle getting rougher than normal - especially when first starting from a cold start.

When the car is in drive and the brake is pressed - the idle is comparitively worse as compared to when the transmission is in park or neutral.

It is a 2005 with approx 46,000 miles.

Any suggestions? Oilhammer - can you describe more your above post?

 

[v8volvo]

So this happens as you are decelerating to a stop, and you get kind of a flutter sensation from the engine while the revs are just above idle at no-load? Does it occur when just idling in gear, or only when moving slightly above idle speed?

If it doesn't occur at a dead stop, only when in no-load low-rev situations with the TC unlocked (such as creeping down a hill at 5mph), then it's a pretty typical phenomenon for a diesel that has an automatic trans and fairly large injectors. Benzes, Powerstrokes, etc do it, and sometimes TDIs, especially if they have had larger injector nozzles put in. My folks' old B5.5 TDI would do it sometimes coming down to a stop. Results from the inability of a large-ish injector nozzle to finely modulate fuel flow when injection quantities are extremely small. If this is a new issue it might be arising due to injector wear as the car has aged. That's where my money would be.

If it does this at in-gear idle too, though, then it's more complicated. Could still be related to injectors but I would guess more electronic, like a sensor with an imprecise or fluctuating reading. Since you have a vag com, start by firing it up and getting into the measuring blocks. Try looking at injection quantity as well as various input values and try to find something that looks like it's off or jumping around too much.

 

[v8volvo]

Aron yours sounds more like worn motor mounts.

 

[je]

I get that a little too - but it's better after the car drives, but, after a long highway trip, the vibration is much stronger. If the car is off for a few minutes and restarted, it's back to normal.

When this vibration occurs, if the clutch is disengaged it's quiet - and louder again when it's engaged. It doesn't happen after cooling down.

Is that worn motor mounts as well? I am guessing it's mostly the dogbone?

 

[dhuddleson]

Dogbone? Clutch?

Are you sure you are in the correct forum? This is for the Passat B5/B5.5 TDI, and in USA/Canada we only have the automatic transmission with our 2.0 PD engine.

 

[MOGolf]

I have been experiencing the idle getting rougher than normal - especially when first starting from a cold start.

When the car is in drive and the brake is pressed - the idle is comparitively worse as compared to when the transmission is in park or neutral.

It is a 2005 with approx 46,000 miles.

Any suggestions? Oilhammer - can you describe more your above post?

This could be excessive inner CV joint play.

 

[Aron]

Rough Idle at Stand Still

When the transmission is in neutral or park the engine idles quite smoothly. However, once the transmission is shifted to drive and the brake is depressed the idle becomes more rough.

In the same configuration, transmission in drive with foot on the brake, and pressing the accelerator (to increase RPM's) the idle does not improve. On the other hand, once the vehicle starts rolling the idle improves - on a similar level when the vehicle is in neutral and not moving.

There is a slight improvement as the engine temperature warms up. Although when waiting at a red light I feel the idle/vibration is excessive. This has been a gradual change (worsening) over the past 4 months.

 

[blaz]

We have a similar situation to Aron. For now, it's just being ignored.

But when the car goes in for the Balance Shaft and Timing Belt replacement (maybe a year from now if it doesn't blow under ext. warranty?), we'll have him look closely at the motor mounts and CV boots/joints.

 

[mparker326]

Hi,

My 2004 sometimes has an uneven idle - not vibration. The engine will skip a beat and then flutter until I add a few rpms. It does this about 10% of the time when I come to a stop sign - the rest of the stops are perfectly normal

Car is chain less, has new fuel filter, cam and lifters are good, intake cleaned about 20,000 miles ago, EGR cleaned the last time I changed oil.

There is no CEL, I have vag com but have not hooked it up yet. When I connect it, what should I be looking for? Any suggestions?

MIKE

Bump up.

I have a similar issue as the OP and it started after my glowplug ecm reflash this summer.

The car idles fine when it first starts. A couple blocks later while stopped at at a stop sign, the engine rpms blip up a just a little and I feel my engine shudder. The rpms then go back down to normal. It shudders every now and again at this point if I sit there and idle. If I increase the rpm's ever so slightly it goes away. If the car is warm, it doesn't do this. In fact it seems to do this right at the point when it is starting to warm up.

Any thoughts? FF was changed about 10k miles ago. Vagcom shows no codes.

 

[MOGolf]

Log measuring blocks group 013 and review later.
This will show how the idle stablization is behaving.

 

[keypecker]

try this......

they are now putting out winter fuel, the cars run crappier, try adding a double dose of Power Service the next tank and see if that helps. Mine has been running much better the last 3 tanks and idling better too.
just my humble, cheap suggestion.

 

[Btravelen]

I logged on tonight to start a thread for this similar problem, but I'll just add to this one.

Seems like this occurred about the time of the glow plug swap/reflash, but My wife drives it and I can't be certain. The car starts sluggishly and smokes and idles rough and stumbles a bit before starting out. Plenty of starting power (new battery), it just doesn't start 'crisply'. It runs pretty smooth at speed, but idles rough when stopped. I was thinking that I should have marked the old glowplugs and asked to see them after they were replaced to see if any were broken. I checked for codes and found none.

I'm planning on scheduling with oilhammer to have the balance shaft done. Maybe he can help figure this out as well....

Take Care

 

[Riles246]

Just wanted to chime in- I am also having this same problem. Is it due to the winter fuel as mentioned?

Rough vibration only when in gear but stopped. Everything is fine in park & neutral.

I had something similar to this last year and had to replace the alternator pulley, but this doesn't feel/sound the same as that did. Thinking of taking it in to the dealership to have it looked at but its such a hassle.

 

[Riles246]

Took it to the dealership to have it looked at- both motor mounts bleeding red.

They want $600 to replace all 3 (he said he'd only charge me $20 for the front mount). My door lock also stopped working ($400), and I'll be due for a timing belt in about 4 months ($1,100). Still chain driven, so I also have that repair to look forward to ($3k?).

All told, I'm looking at about 5-6k to keep a car worth 9k on the road... buh bye TDI! I really wish I had purchased a gasser- all of these issues just werent worth saving at the pump (also had alternator pulley and glow plugs done last year at a cost of nearly $600).

I'll be leasing from now on so that I don't have to deal with long term issues such as these. Shoulda learned my lesson after my old Lincoln LS blew a tranny at 100k and my Firebird differential went out at 95k. Oh well, now I've learned.

Perhaps a new manual transmission CC is in my future? Leased, of course.

 

[dhuddleson]

Riles,

Some comments:

(1) Timing job $1,100 but could be combined with Balance Shaft. Well in fact you HAVE to take off the Timing Belt to get to the Balance Shaft assembly. And therefore, subtract your $1,100 from the BS job. Really, the BS job is about $1800 more than the Timing job.

(2) Steel Glowplugs. You paid for those? Get the refund from VW! You are entitled to it due to VW's recall this summer. Save that cash cha-ching...

(3) Engine mounts. Could happen in any car, have you priced ones for a 1.8T or V6 Passat? Maintenance item...

Don't think your numbers add up...

 

[Brian's96TDIPASSAT]

Ever since my 05 was new I've noticed that when the temps dip to around 40F the car will not idle as smoothly. I can duplicate it anytime, once 50 is reached, smooth as silk. It is most noticeable with the brake depressed, gets better in Neautral. I've also noticed that the very few times I went nearly 10K with my oil that the cars idle will get worse. As soon as I do the LOF, it's back to normal so I change the oil at 5K.

 

[MOGolf]

With the exception of the door lock problem (I haven't researched), those repairs (BSM, timing belt, engine mounts) should all be done at the same time. You'd be looking at 1/2 the cost or less probably if done by someone other than that dealership.

 

[Riles246]

You both make a great point. I should have combined the repairs into one job.

That still leaves me at roughly 3,400 (BS + timing belt + engine mounts), plus another 400 for the door lock. And I'll admit- I'm terrified of ending up in a sloopy snood position- pay all that money, just to have something like a transmission fail a week later.

It's probably pretty apparent, but I've lost trust in this car. I didn't expect these kinds of repairs at only 86k miles.

I will miss the community, though- of all the forums I've been a member of over the years, this one clearly has the smartest and most technical members who always seem to have an answer.

 

[mparker326]

That still leaves me at roughly 3,400 (BS + timing belt + engine mounts), plus another 400 for the door lock. And I'll admit- I'm terrified of ending up in a sloopy snood position- pay all that money, just to have something like a transmission fail a week later.

It's probably pretty apparent, but I've lost trust in this car. I didn't expect these kinds of repairs at only 86k miles.

You will lose more than the repair cost in depreciation if you sell the car now.

SS's bad luck happened at 100K more miles than you have now. Look at it this way. He did practically no maintenance and got almost 200k miles out if it.