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vwbugman, VW Technician
Category: VW
Satisfied Customers: 821
Experience:  35 years experience on VW air cooled and water cooled repair and restoration
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2001 vw jetta tdi, surging at idle when warm

Customer Question

2001 vw jetta tdi, surging at idle when warm
Submitted: 8 years ago.
Category: VW
Expert:  vwbugman replied 8 years ago.

How many miles are on your TDI?
Customer: replied 8 years ago.
only 286k performing 100% OTHERWISE. after driving a substantial distance, then parking for 5 mins to 1 hr and restarting, surges 900 -1300 rpms
Expert:  vwbugman replied 8 years ago.
There are a couple of things that come to mind. One is make sure the EGR Valve and intake manifold are not carboned up. I normally have to clean them every 60 to 80,000 miles. It will actually close up with carbon and restrict air flow and make the EGR valve malfunction. Secondly, the diesel pump may just have a lot of wear and it is putting out too much fuel at idle. The only way this can be checked is by the dealer or a repair shop with a VW specific scan tool such as VAG-COM. With this tool, you can go in and look at the the pump timing and start injection quantity. I have the start injection quantity many times but you have to have the software and login to get the readings. Most dealers will not do this but would rather sell you a pump if it is off. Remove the hose from the intake where it connects to the EGR valve and look at the inside with a flashlight. See how much carbon is accumulated. This may not solve this problem but will help with starting and performance issues if corrected.
Customer: replied 8 years ago.
my egr is bypassed so there is no carbon build up
Expert:  vwbugman replied 8 years ago.
You can still have buildup. This comes from the turbo.