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Author Topic: insufficient turbocharging S4 B5  (Read 10977 times)
shelev
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« on: January 27, 2018, 01:19:30 AM »

Hi. Recently I began facing this problem: insufficient turbocharging.
I've got original ABT chip (1.3 bar), and during the winter the pressure was alright, it held the claimed 1.3 with no problem, but by the end of April the pressure dropped down to 0.9 and it only slowly escalates to 1.2 at 5500-6000rpm on 5th and 6th shift!
Logs show that 115th group requests 2300mbar@3300 rpm,the engine gives only 1980 a maximum.
Also, i experienced the (Check Engine) error 17965 - boost pressure control output exceeds the control range (higher than the upper limit), but what's interesting is that it only shows itself after 60-90 minutes of the engine off. When I approach any red traffic light, I just restart the engine and it continues operating normally with no errors, and doesn't fall back into "Check Engine" state during the ride.
What's replaced:
1. N75 valve (took the one from a TFSI)
2. Charge pressure sensor (new)
3. N249 valve (new)
4. Bypasses
5. Camshaft chains (original)
6. Throttle
7. Detonation sensors, new, original, tightened at 20N force
8. All new lambda-probes (exhaust sensors)
9. AEM 50-1000 gasoline pump, replaced in February
10. Changed the accelerator pedal, no effect
11. Air Flow Mass Sensor - I have 3 new identical parts, all three change nothing
Did not replace:
- ignition coils (no, we tried replacing them but it had no effect and we returned the old set back)
- spark plugs (they're still looking awesome)
- N80 fuel tank vent valve
- gasoline filter
- switches (commuters)

About the turbines themselves:
1. Hoses for the wastegates are pressure-tested
2. Turbines are alive and in a great condition (it easily gains 1.6 bar when I detach the wastegate hose)

Engine totally is in a nice shape, doesn't burn oil and operates with no suspicious sounds.

Audi S4 B5, the engine code is BES
« Last Edit: January 27, 2018, 01:26:14 AM by shelev » Logged
KasperH
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« Reply #1 on: January 27, 2018, 02:46:18 AM »

What maps did you change to accommodate the N75 valve from a TFSI?
and why did you change to a N75 from a TFSI?
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shelev
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« Reply #2 on: January 27, 2018, 03:41:18 AM »

What maps did you change to accommodate the N75 valve from a TFSI?
and why did you change to a N75 from a TFSI?

I didn't change the card
In Russia everybody uses those for valves
t just the same on functionality, but costs cheaper
I have changed the valve after this mistake began to appear
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KasperH
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« Reply #3 on: January 27, 2018, 05:04:36 AM »

They might be mechanically the same but flow might be different.
Have you tried new stock N75 valve?

Have you leak tested boost piping?
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shelev
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« Reply #4 on: January 27, 2018, 05:14:47 AM »

They might be mechanically the same but flow might be different.
Have you tried new stock N75 valve?

Have you leak tested boost piping?
No, they identical, our cars 800 HPs go by TFSI
At me 4 such N75 valves change nothing

Pressure tested
No leaks
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KasperH
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« Reply #5 on: January 27, 2018, 05:22:35 AM »

Post some logs with me7logger of some decent pulls,
then it will be much easier to diagnose your problem Smiley
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shelev
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« Reply #6 on: January 27, 2018, 05:25:34 AM »

Post some logs with me7logger of some decent pulls,
then it will be much easier to diagnose your problem Smiley

I have Logs 115 - 114 groups
I can send to an email
« Last Edit: January 27, 2018, 11:03:16 AM by shelev » Logged
shelev
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« Reply #7 on: January 27, 2018, 05:39:21 AM »

Post some logs with me7logger of some decent pulls,
then it will be much easier to diagnose your problem Smiley
1 - when she went well

2-pressurization and consumption of air when went well

3-Nadduv and opening of wastegates 115 - 114 group already insufficient turbocharging

4-Pressurization opening of wastegates and temperature of an admission when insufficient turbocharging
« Last Edit: January 27, 2018, 05:53:40 AM by shelev » Logged
KasperH
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« Reply #8 on: January 27, 2018, 05:55:24 AM »

Can't really tell much from VCDS logs.
The "pulls" have 5-15 data points and not enough sets.

A 3rd gear pull from as low as you can to redline. Full throttle.

But i can tell you that it doesn't request 1.3 bar for very long.

Are you on stock turbos?
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shelev
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« Reply #9 on: January 27, 2018, 06:00:11 AM »

Can't really tell much from VCDS logs.
The "pulls" have 5-15 data points and not enough sets.

A 3rd gear pull from as low as you can to redline. Full throttle.

But i can tell you that it doesn't request 1.3 bar for very long.

Are you on stock turbos?
Yes,stock turbos
Yes I know that  the Logs of a curve, will change turbines for new now and I will write down the log anew if of course the problem doesn't leave
« Last Edit: January 27, 2018, 11:03:58 AM by shelev » Logged
shelev
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« Reply #10 on: January 27, 2018, 06:20:52 AM »

Can't really tell much from VCDS logs.
The "pulls" have 5-15 data points and not enough sets.

A 3rd gear pull from as low as you can to redline. Full throttle.

But i can tell you that it doesn't request 1.3 bar for very long.

Are you on stock turbos?

At present I have a problem with the turbine because of low-quality oil
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KasperH
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« Reply #11 on: January 27, 2018, 06:52:48 AM »

That is a pretty sweaty turbo.
How much shaft play do you have?
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shelev
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« Reply #12 on: January 27, 2018, 07:08:13 AM »

That is a pretty sweaty turbo.
How much shaft play do you have?

Bad Mobil oil ((
I have so understood you about the free movement of a shaft of the turbine
last time she was very close to walls
« Last Edit: January 27, 2018, 07:15:26 AM by shelev » Logged
KasperH
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« Reply #13 on: January 27, 2018, 07:54:56 AM »

It's fine if the compressor is close to the walls (if it's within spec), That's part design.
But, it should never touch the walls, but have enough room to expand when hot.

But if there is a lot of play in the shaft, that's a sign of a turbo on its way out.
That might contribute to your underboost problem.

But can't really specify better, without some decent logs with me7logger.
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shelev
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« Reply #14 on: January 27, 2018, 08:17:58 AM »

It's fine if the compressor is close to the walls (if it's within spec), That's part design.
But, it should never touch the walls, but have enough room to expand when hot.

But if there is a lot of play in the shaft, that's a sign of a turbo on its way out.
That might contribute to your underboost problem.

But can't really specify better, without some decent logs with me7logger.

I want to change turbines on new next week
Have sent me the new Audi Rs4 B5 engine, I want to use this while I wait for other motor
« Last Edit: January 27, 2018, 08:21:29 AM by shelev » Logged
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