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Go Back   TDIClub Forums > TDI Model Specific Discussions Areas > VW MKIV-A4 TDIs (VE and PD)

VW MKIV-A4 TDIs (VE and PD) This is a general discussion about A4/MkIV Jetta (99.5-~2005), Golf(99.5-2006), and New Beetle(98-2006). Both VE and PD engines are covered here.

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Old December 1st, 2009, 19:31   #1
Jesse_Boyer
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Default idle studder... at odd times

Recently, I bought another TDI to have as a spare, but I'm struggling to figure out an idle stumble. The car seems to run perfectly down the road at all speeds, but experiences an odd stumble while rolling to a stop. I can hear the motor start to stumble at approximately 7-10mph, but it completely smooths out when the car comes to a stop. It may be starting before 7mph, but I can't really hear it until that point. It will do it if you start from a stop, let off as soon as the car is moving, and listen... forward or reverse.

Any suggestions would be appreciated.
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Old December 1st, 2009, 21:00   #2
Wook660
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search "slow down shutter" "Injection Quantity Adjustment" and "Hammer Mod" and see if they relate to your circumstance
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Last edited by Wook660; December 1st, 2009 at 21:02.
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Old December 3rd, 2009, 09:18   #3
ofhs93
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As Wook stated...Check the IQ...I'm willing to bet money that is your issue...it's not at all uncommon with these
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Old December 3rd, 2009, 09:23   #4
Ski in NC
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Mine does that and has for several years. I just ignore it.
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Old December 3rd, 2009, 16:55   #5
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Quote:
Originally Posted by Wook660
search "slow down shutter" "Injection Quantity Adjustment" and "Hammer Mod" and see if they relate to your circumstance
This was my suspicion as well. I'd read about it on this forum, but didn't have VAGcom to check. I know a local 'tdi guru' and checked with him to see if we could use his VAGcom to check on the IQ. The IQ was 1.0-1.2 and after some adjustment, it's 3.4-3.6. The 'guru' spent nearly 90-minutes, charged me $50, and didn't fix my 'slow down shudder.' I'm slightly frustrated with my evening thus far...

Any other thoughts, gang?
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Old December 3rd, 2009, 17:29   #6
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I toyed with my IQ setting for a while and was able to cure the problem. Eventually my IP started going bad and I was unable to set the IQ. The value would fluxtuate back and fourth as did the timing on the graph. Not saying your pump is bad, but I had to replace mine with a cheap used one I bought off a fellow member that is currently working great. I'll send my original pump out for overhaul when my next TB is due.

How many miles are on the car?
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Last edited by Wook660; December 3rd, 2009 at 17:32.
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Old December 3rd, 2009, 17:37   #7
Jesse_Boyer
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205k

Can anyone tell me why the 'studder' happens when rolling at very low speeds, but completely goes away once the car stops?

Timing and IQ were quite solid per Vagcom
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Old December 3rd, 2009, 18:56   #8
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What is the IQ though? I had it for years.

Here is a how to I made...

http://forums.tdiclub.com/showthread...95#post2689895
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Old December 3rd, 2009, 18:59   #9
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Maybe this is related to the DMF and not the engine.
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Old December 3rd, 2009, 21:42   #10
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brand new OEM clutch. Rrolling' speed should not matter regarding idle, clutch or otherwise, right?. It's unmistakable though. You can hear it start as car slows down and it completely stops as the car stops.

IQ is 3.4 as stated above.

(going to bed)
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Old December 4th, 2009, 05:16   #11
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Quote:
Originally Posted by Jesse_Boyer
This was my suspicion as well. I'd read about it on this forum, but didn't have VAGcom to check. I know a local 'tdi guru' and checked with him to see if we could use his VAGcom to check on the IQ. The IQ was 1.0-1.2 and after some adjustment, it's 3.4-3.6. The 'guru' spent nearly 90-minutes, charged me $50, and didn't fix my 'slow down shudder.' I'm slightly frustrated with my evening thus far...

Any other thoughts, gang?
Hmm...I can set a IQ is less than 5 minutes. Either 1. you have a bad guru or 2. you have a bad pump. At 3.4, you should not have any shuddering.
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Old December 4th, 2009, 05:50   #12
Jesse_Boyer
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As can I, but I don't have VagCOM. Needless to say, I'll be ordering it ASAP.

He actually spent most of the time tinkering around, doing things I didn't ask him to do. Yes, I know there are issues I have to solve with that car... but I don't need or want to pay you $50/hr to do 95% of them.

Regardless, can this still be an IQ issue? It's set at 3.4mg/st... which I thought was optimal for most cases.
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Old December 4th, 2009, 06:38   #13
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perhaps yours needs adjusted to be a little higher. I know if I had charged someone to set their IQ, and they weren't happy, I would do my best to make it right.

have you discussed this with your guy?
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Old December 4th, 2009, 07:27   #14
Ski in NC
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I'm a novice on this electronic diesel, but the way I understand the "slowdown shudder" is that engine is operating on one control map when car is moving, then transitioning to another map when car is stopped. In that transition, it "hands off" from one map to another and if iq is so and so, it does it smoothly. If iq is off, it will shudder. Not a big deal, and I am certainly used to it.
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2001 Jetta TDI 5sp Stock 201k mi
1981 Rabbit IDI 4sp Sold at 339k mi
1990 S-10 4.3 4wd 5sp 154k mi
1986 VW Pathfinder 1.6 45hp Marine 4700 Hrs
2001 Cummins 8.3 420hp Marine 1660Hrs..REFIT DONE!!
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Old December 4th, 2009, 19:33   #15
Jesse_Boyer
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I'm going to do a bit more research and order VagCom later... then I'll try to tweek the IQ.

ordering the timing belt kit this weekend as well... so I'll need it anyway.
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