1.9TDI AVF hesitating/lagging when accelerating hard

A

afourb6

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Joined
Jan 7, 2020
Location
Norway
TDI
Passat 1.9TDI 3BG, A4 B6 1.9TDIQ, A3 8P 1.9TDI
Audi A4 B6 1.9TDIQ AVF hesitating/lagging when accelerating hard. Specially noticeable in 4th and 5th between 2000-3000rpm.

What ive done so far:

New injector wiring harness.
Tried other MAF.
Tried other MAP.
New fuel filter.
Cleaned EGR.

New turbo 25000km ago.

Graph when accelerating in 4th:

https://ibb.co/HHXXKvG

Different values with warm engine on idle:

https://ibb.co/gVDcY79

N75? Turbo Actuator?

Anyone got any tips?
 
Last edited:
Y

Yourbuddysatin

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Oct 28, 2016
Location
Pennsylvania
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2013 Jetta tdi
Well if you had a mechanical boost gauge you could see if the needle is dipping up and down under acceleration. My old Jetta did that and here the veins were all gummed up. I had about the same mileage on mine.
 
jmodge

jmodge

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2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
I am curious why your IQ is set so lean? 10.2 and it is idling low
 
jmodge

jmodge

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2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
4.5-5.5 generally speaking, once it blows black, I lean it out and shoot for a blue haze under full throttle runs.
 
G-Lab

G-Lab

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lower means better injectors condition, 10mg to keep idle means either PD's are worn or no pressure from tandem pump, how does 023 look like? Tandem pump press within specs?
 
jmodge

jmodge

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2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
after that I adjust actuator rod length, paying particular attention to off idle balance of specified and actual boost readings. First at full throttle and then normal driving, whatever that happens to be.
 
G-Lab

G-Lab

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according to boost log (as far as i can tell from log without axes) boost looks quite allright, not perfect but assuming lack of fuel it might be like that, wouldn't touch it. raw vcds csv file 001, 008, 011 at full load would be helpful,
 
A

afourb6

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Joined
Jan 7, 2020
Location
Norway
TDI
Passat 1.9TDI 3BG, A4 B6 1.9TDIQ, A3 8P 1.9TDI
G-Lab said:
lower means better injectors condition, 10mg to keep idle means either PD's are worn or no pressure from tandem pump, how does 023 look like? Tandem pump press within specs?
Click to expand...
Will check that out tomorrow:)
 
G-Lab

G-Lab

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Elementary my dear Watson: you want to know:
vcds:
004 023 at idle (if 023 look allright lets say under 30, no need to check fuel press)
001, 008, 011 at full load (higher gear is better, take a log of hasitation)
and please don't convert csv to images :)
 
A

afourb6

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Jan 7, 2020
Location
Norway
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Passat 1.9TDI 3BG, A4 B6 1.9TDIQ, A3 8P 1.9TDI
Last edited:
A

afourb6

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Jan 7, 2020
Location
Norway
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Passat 1.9TDI 3BG, A4 B6 1.9TDIQ, A3 8P 1.9TDI
Also, the car seems to run fine when its cold.
The hesitation/lag comes when the car is hot.
 
G-Lab

G-Lab

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You want to review the tune.
your injection duration is quite low and limited by maf which isn't great.
 
A

afourb6

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Joined
Jan 7, 2020
Location
Norway
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Passat 1.9TDI 3BG, A4 B6 1.9TDIQ, A3 8P 1.9TDI
The other ECU wasnt the same part number..
Should i get a new tune?
 
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