Best VCDS tweaks for a B4

Just got my KII in the mail yesterday, and have already been digging and researching more. Used it to adjust my IQ, which was previously set to about 5.2.

What are some "must-have" VCDS tweaks that you know of? I know there's not as much functionality here as there be in a newer car, but I'm sure there are several things that people enjoy doing in their personal vehicles.

I have the same questions so I will be watching with anticipation.

There's some good ideas here: http://tdiclub.com/TDIFAQ/TDiFAQ-7.html

The software seems to have changed a bit but you can still find the settings with a few searches. Specifically, I checked my timing (was having really hard starts, found out it was out of spec so I adjusted to to slightly advanced), verified my MAF sensor works correctly, "tuned" out the EGR and did the "slowdown shutter" adjustment. Though I feel like I've just scratched the surface with this tool, especially with all the real-time diagnostics you can run. Interested to hear more ideas.

The B4 TDI (1996 1Z engine with BK or GQ ECU, 1997 with AHU and FA ECU) have open loop EGR. There is no feedback, no electronic monitor, nothing to "tune" out. Just disconnect the vacuum hose at the EGR actuator and plug the hose.

The slow-down shudder is an ALH issue. The 1Z and AHU don't have the throttle plate in the intake to create vacuum in the intake during engine stop to reduce the abrupt stop of compressing a full slug of air.

The only really useful VCDS tweaks I found for the early TDI was the glow plug time and onset temperature, and the idle speed for slower in summer, faster in winter.

Lug_Nut said:

The B4 TDI (1996 1Z engine with BK or GQ ECU, 1997 with AHU and FA ECU) have open loop EGR. There is no feedback, no electronic monitor, nothing to "tune" out. Just disconnect the vacuum hose at the EGR actuator and plug the hose.

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No direct feedback, but there is inferred feedback from MAF readings that usually does trigger an EGR code if the hose is simply unplugged without also turning down the EGR duty cycle.

Chris Bell said:

No direct feedback, but there is inferred feedback from MAF readings that usually does trigger an EGR code if the hose is simply unplugged without also turning down the EGR duty cycle.

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Correct - My CEL was on until I set 33768 as my new adaptation value. No more CEL.

Chris Bell said:

No direct feedback, but there is inferred feedback from MAF readings that usually does trigger an EGR code if the hose is simply unplugged without also turning down the EGR duty cycle.

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I didn't suggest that the 1Z/ AHU EGR actuator hose be "simply unplugged". My words were disconnect the vacuum hose at the EGR actuator and plug the hose. There's still no feed back, direct or inferred, on the 1Z and AHU.

The MAF flow rate change as an indication of EGR operation needed an "Epsilonian Device" to keep the early ALH engines from producing a fault when the EGR on those were modified to more than the tolerance the ECU would accept.

Lug_Nut said:

There's still no feed back, direct or inferred, on the 1Z and AHU.

The MAF flow rate change as an indication of EGR operation needed an "Epsilonian Device" to keep the early ALH engines from producing a fault when the EGR on those were modified to more than the tolerance the ECU would accept.

Click to expand...

The GQ and FA ECUs interpret high MAF flow under conditions where EGR flow is specified as an EGR fault exactly as ALH ECUs do. BKs did not, AFAIK.

My B4V Has an intake manifold with a blanked EGR valve (cut out with a bolt through it to stop flow). I get an EGR code, and I have an FA ECU. Happens within a minute of starting it up after erasing code.

Must be a New England thing.

Two B4 sedans (ran both BK and GQ), 3 B4 wagons (BK and GQ in two, FA in the last one), 3 A3 (ED and JB), none with faults from disconnected and plugged EGR actuators.

How about my 1Z with GQ ecu, no codes with a simply disconnected EGR actuator. No plug and I found the hose just lying about, I'm assuming by a PO.

There are definitely variations car-to-car. In this thread alone, 3 had it, 2 didn't. I've seen similar variations in other threads.

If Bentley is correct (always a question), the '96 OBD-D system with the BK ECU did not have a specific EGR flow DTC but did fold an interpretation of too high or too low EGR flow into the 00553 MAF flow DTC.

The '96 GQ and '97 FA OBD-II systems added a specific EGR flow DTC, 00560.

I would expect the BKs to be less sensitive to an EGR-caused DTC and the GQ/FA to be more so.

I'm guessing the car-to-car variability has to do with variations in the age, condition, cleanliness and calibration of the MAF. Also, if the N18 duty cycle has been turned down to minimum in VCDS along with EGR disablement, odds of a DTC decrease.

I have to change my answer, the CEL was gone for like a day and now it's back with the P1403 code. (I think that's the right one)

P1403 = 00560 vag