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Author Topic: 1.8t AUQ 630cc - fueling issues  (Read 1537 times)
maxwell_ck
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« on: December 18, 2023, 03:04:48 PM »

Hello nefmoto!
I am currently looking for a problem causing potential fueling issues that are bothering me, especially the Lambda Controller values at Group 1.
Please find attached the logfile. I was trying not to ecceed the 3k rpm.

Setup:
1.8t AUQ
630cc Bosch injectors
3bar FPR
3" MAF
Sytec 300l/h fuel pump
K04-064 - TTE420

I have checked all the intake for leaks, vacuum seems to be ok, replaced fuel filter.
In addition there is a (+- 20-25) positive Lambda Controller correction in Group 001 at idle after clearing the LTFT/STFT.
What would you recommend to check?
Any help appreciated  Wink
« Last Edit: December 18, 2023, 03:18:41 PM by maxwell_ck » Logged
aef
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« Reply #1 on: December 19, 2023, 12:49:14 AM »

krkte, tvub, temin

fuel pump overkill for the stock fuel pressure regulator

try to measure the fuel pressure in the rail with 2nd car or 13.8v attached to it.

did it work before or does it come with the 630cc?
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maxwell_ck
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« Reply #2 on: December 19, 2023, 09:24:41 AM »

KRKTE - 0.05195 wondering if I should increase it to ca. 0.05295 due to E5 pump gas.

TEMIN - 0.70 ms

TVUB:
7.96   2.07
10.00   0.96
11.97   0.69
14.01   0.46
15.98   0.40

It worked ok before with 430cc injectors and stock fuel pump.
I will measure the fuel pressure.
Is it necessary to switch to 4bar FPR with Sytec pump?
« Last Edit: December 19, 2023, 09:59:12 AM by maxwell_ck » Logged
aef
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« Reply #3 on: December 19, 2023, 03:35:03 PM »

http://nefariousmotorsports.com/forum/index.php?topic=4345.msg81386#msg81386

part number of your injectors?
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maxwell_ck
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« Reply #4 on: December 19, 2023, 10:58:57 PM »

0280158123
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aef
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« Reply #5 on: December 19, 2023, 11:52:10 PM »

http://nefariousmotorsports.com/forum/index.php?topic=21399.msg157585#msg157585
https://www.finjector.com/documents/6450c9f86cb90/0280158123_Data.pdf
http://nefariousmotorsports.com/forum/index.php?topic=19978.0title=
http://nefariousmotorsports.com/forum/index.php?topic=11289.0
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JeanAwt
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« Reply #6 on: December 20, 2023, 12:50:49 AM »

This interests me, pump flow / frp size. I have 265l/h frp stock 4 bar full 'e85'. for better diffusion/spraying or other is there any interest in switching to frp 4.5/5 bar?
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A4 B5 avant 1.8T 2000 NO QUATTRO
ratosluaf
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« Reply #7 on: December 21, 2023, 03:08:02 AM »

It's tricky because

Higher fuel pressure = less flow at pump

Higher fuel pressure = more flow at injectors

It's nonsense to switch to such high FPR. I always try to stick with 3 bar FPR, 4 bar only when it is installed from factory or we need to squeeze everything out of injectors. In any other case this is better to obtain injectors that are capable of flowing more and have less pressure.

Also, have that in mind that effective pressure is fuel pressure + boost pressure. So with 5 bar FPR and 1 bar of boost your pump needs to pump 6 bar. For example, 255lph deatschwerks can only flow 150lph at 6 bar. Its useless and nonsense.
« Last Edit: December 21, 2023, 03:12:53 AM by ratosluaf » Logged
JeanAwt
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« Reply #8 on: December 22, 2023, 11:49:06 PM »

thank you, yes that seems logical. I have never checked my fuel pressure on my 1.8t, the sl racing 265l/h and frp 4 pump are recent but nothing proves to me that I have 4 bar. I imagine I need a special gauge to connect to the rail pipe where I don't remember if there is a sensor... I was looking for why I had oscillations in idle in fact I turned much too rich e85 winter must be around 60 /65% obliged to remove all my cold start maps I reduce I just have fkstt left at 8% and that will end up in stock. and 0280158117 krkte 0.0704 . by the way if someone can give me the complete list of variables to log the fuel because I must have forgotten some. thank you
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A4 B5 avant 1.8T 2000 NO QUATTRO
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