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Old November 8th, 2015, 16:10   #46
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Join Date: May 2015
Location: Naperville, IL

So true growler me and my friend were messing with IP it squirted all over the windshield and engine luckily no windshield hazing, and engine was fine but it ruined the stock markings. The IP tune is always cool at first until you fill up and got 350 miles and about 29 mpg. And my brakes are sticking as well so I'm trying to set the IP back to stock. If anyone can slove my brake problem I'd be so happy check out my threadhttp://forums.tdiclub.com/showthread.php?t=448238. Thanks
TDIs: 2003 Jetta GL TDI, 5 speed manual (02J), Galactic Blue (LG5V), DRL Delete mod, with over 101k miles on the odometer. New Focal F06 16" rims black painted with special chrome lug bolts. New TB done @ 98,559 mi
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Old January 18th, 2017, 13:34   #47
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Location: Piedmont of N.C. & the plains of Colorado
Fuel Economy: 64 .1city @ 30-60 mph/ 52-53 @ 70-85 mph hyway ( 52 to just under 60 normal around town)on LSD
Question What is the mechanical reason why this is happening?

I picked up a low mile 99.5 Jetta which seems to have started having this issue recently. What is the mechanical reason why this is happening?

I also have a friend with 300k+ miles on the same car purchased new around the same time that is also suffering from the shudder & hard hot start issue. What is the mechanical problem which is causing this problem?

Is the pump timing & fueling control not moving the same distance as it did when the pump was newer due to wear or other age related reasons???

More diesels than I can list
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Old December 31st, 2017, 16:47   #48
Join Date: Dec 2017
Location: Austria


my A4 with an AFN Diesel had stuttering problems at low revs specific under 1500rpm down to idling.
Very annoying especially in the city at low speed and stop & go traffic.

I then checked the IQ with vcds - it was at 32768 - 1,2mg.
32686 is the smallest possible value what led to 2,8mg.
Its much better now but not yet perfect.
Because the electrical adjustment is fully exhausted, I would have now
do the hammer mod to increase the value further.

Do you think the effort is worth it?
Or is the expected improvement from 2,8mg to the optimal 4-5mg not really a big deal?

Because I have read of pumps which be leaking after the adjustment.
And my pump is bone-dry so... hmmm maybe I should rather keep my fingers off?!
Is this a common problem or rather rare?

Thank you,

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Old December 31st, 2017, 17:01   #49
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Location: PNW

Martin, you adjust in order to achieve proper operating performance. If you don't have it, and you've exhausted the available range via Adaptation (VCDS) then, yes, you'd need to do the Hammer Mod to further achieve a change. Always set the Adaptation value back to stock before performing a Hammer Mod.

If your pump is "bone dry" then you've got much bigger problems than a simple IQ problem.
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Old January 8th, 2018, 08:59   #50
Join Date: Dec 2017
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Hi UhOh,

with "bone dry" I meant it does not leak but I am scared that it does after the hammer mod because who knows how old the gasket is and if it take the move without beginning to leak.

The question is if the effor is worth the risk.
If the expected improvement from 2,8mg to the optimal 4-5mg is really noticeable or after all I have more trouble as now because I have to reseal the pump.

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