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I don't know if the condition of Kristiyan's customized car is compatible with these experimental mods.
ALT-LIN does not fix for pre-existing mechanical engine issues.
> He is dealing with an odd combination ...:
+ straight pipes
+ high crankcase blow-by
+ poping engine dipstick
+ customized ECU firmware
+ MOD-2: 5W-40 "MB Approved"
+ combined with ALT-LIN...
-- You know as soon as something goes weird, everyone is quick to point at the unknown as being the cause, right?
-- I clearly point at pre-existing condition:
Without blow-by, custom pipes and firmware the ECU responds remarquably well with improvements.
-- The bottom line is the crankcase back pressure is affecting the fine control ECU has over engine Rpm.
-- It's feeding intake pressure at idle.
-- This is significant near idle when volumes are small.
-- This is 100% what's causing tranny poor shifts. > Once ECU has good Rpm control tranny gets SILKY PREDICTABLE.
> The combination of ALT-LIN MOD-4 further help deliver that to otherwise stock engines.
Once you think you have identified the root cause you can go about fixing it... you won't be sure until it is fixed!
-- The first thing I'd do is refresh PCV to stock. It has some kind of silicone diaphragm on spring that shuts off -- diaphragm falls apart to leak pressure through.
-- Drafty pistons rings. This is the engine killer. Engines go the way they are driven!
Don't blame anyone or anything for ignoring unbalanced condition.
I do not know how to seal an engine under red-line duty, only moderate duty.
Personally I used oiling and mileage below 3000.Rpm with great results.
Viscosity "artificial seal" hurts unbalanced engine timings. So it is safer to use stock oil that cause burnt carboned rings: a catch-22 !!!
> A WAY OUT...
-- The escape out of this self-feeding chaos is to use non-burning setup under easy output Rpm
-- The sealed balanced result may materialize if bores are not ovaled, then engine can get seriously rev'ed up.
> SPIRAL AROUND ....
Burning oil on dry rings is guaranteed to unbalance any engine. Pistons are so extremely hot LSPI ignites calcium/carbon deposits!
You may want to research how to seal/cleanup drafty cylinders in high rev'ing turbo applications... DUNNO! (special valvoline oil ?? flush treatment ??).
Fix the engine blow-by safely then your ECU/TCU will improve Rpm fine controls.
+++ NEVER MIND IDLE RPM....
I think the top priority here is to quit stressing pre-existing conditions.
+++ SUMMARY +++
Mods are not a fix for existing mechanical issues.
+++ STOCK: BRILLIANT IDEA...
When in doubt resume stock conditions with managed voltage and recommended "MB approved" oil minder.
let me bring more details when i stop at traffic light
if i stop normal like you expect when you are passenger in a car then the swing rpm doesn't happen
but if i decide to stop bit more quick then the car do this swing rpm
anyway i would stay with ALT and solenoid unplugged, just not sure if float battery might be the reason to have this behaviour (i don't have yet ctek battery charger to test)
let me bring more details when i stop at traffic light
if i stop normal like you expect when you are passenger in a car then the swing rpm doesn't happen
but if i decide to stop bit more quick then the car do this swing rpm
anyway i would stay with ALT and solenoid unplugged, just not sure if float battery might be the reason to have this behaviour (i don't have yet ctek battery charger to test)
Your Rpm control issue is not electrical, it's mechanical.
How old is your crankcase breather system?
it's not just the plastic part at bank1 rear, the whole conduit pipe gets plugged up with burn deposits. Need to be replaced at once to restore effectiveness.
let me bring more details when i stop at traffic light
if i stop normal like you expect when you are passenger in a car then the swing rpm doesn't happen
but if i decide to stop bit more quick then the car do this swing rpm
anyway i would stay with ALT and solenoid unplugged, just not sure if float battery might be the reason to have this behaviour (i don't have yet ctek battery charger to test)
Ok, this time you described it, I can confirm my car doesn't act like as described before or after unplugging. I wonder if it has to do with ALT-LIN and the conjunction with your tune?
That's because ECU has a tight control on the engine Rpm. ALT-LIN further extends that with fine granularity below 2500.Rpm.
The result is extremely precise throttle control to the point pedal becomes pressure sensitive. Tranny self-adapts extremely well.
The opposite is poorly controlled Rpm and associated bangy shifts. Poor shifts are a direct sign of limited throttle control.
> MAGIC DELTA...
The difference better oiling brings is lower blow-by from cooled pistons for sealed contributions. ECU picks up on the way crank rotates evenly vs. jerky jittery uneven.
Oil pump solenoid also affected the pedal responsiveness, ALT-LIN however further improved that when you thought there were no rooms for improvement.
I don't know if the condition of Kristiyan's customized car is compatible with these experimental mods.
ALT-LIN does not fix for pre-existing mechanical engine issues.
> He is dealing with an odd combination ...:
+ straight pipes
+ high crankcase blow-by
+ poping engine dipstick
+ customized ECU firmware
+ MOD-2: 5W-40 "MB Approved"
+ combined with ALT-LIN...
-- You know as soon as something goes weird, everyone is quick to point at the unknown as being the cause, right?
-- I clearly point at pre-existing condition:
Without blow-by, custom pipes and firmware the ECU responds remarquably well with improvements.
-- The bottom line is the crankcase back pressure is affecting the fine control ECU has over engine Rpm.
-- It's feeding intake pressure at idle.
-- This is significant near idle when volumes are small.
-- This is 100% what's causing tranny poor shifts. > Once ECU has good Rpm control tranny gets SILKY PREDICTABLE.
> The combination of ALT-LIN MOD-4 further help deliver that to otherwise stock engines.
Once you think you have identified the root cause you can go about fixing it... you won't be sure until it is fixed!
-- The first thing I'd do is refresh PCV to stock. It has some kind of silicone diaphragm on spring that shuts off -- diaphragm falls apart to leak pressure through.
-- Drafty pistons rings. This is the engine killer. Engines go the way they are driven!
Don't blame anyone or anything for ignoring unbalanced condition.
I do not know how to seal an engine under red-line duty, only moderate duty.
Personally I used oiling and mileage below 3000.Rpm with great results.
Viscosity "artificial seal" hurts unbalanced engine timings. So it is safer to use stock oil that cause burnt carboned rings: a catch-22 !!!
> A WAY OUT...
-- The escape out of this self-feeding chaos is to use non-burning setup under easy output Rpm
-- The sealed balanced result may materialize if bores are not ovaled, then engine can get seriously rev'ed up.
> SPIRAL AROUND ....
Burning oil on dry rings is guaranteed to unbalance any engine. Pistons are so extremely hot LSPI ignites calcium/carbon deposits!
You may want to research how to seal/cleanup drafty cylinders in high rev'ing turbo applications... DUNNO! (special valvoline oil ?? flush treatment ??).
Fix the engine blow-by safely then your ECU/TCU will improve Rpm fine controls.
+++ NEVER MIND IDLE RPM....
I think the top priority here is to quit stressing pre-existing conditions.
+++ SUMMARY +++
Mods are not a fix for existing mechanical issues.
+++ STOCK: BRILLIANT IDEA...
When in doubt resume stock conditions with managed voltage and recommended "MB approved" oil minder.
Your Rpm control issue is not electrical, it's mechanical.
How old is your crankcase breather system?
it's not just the plastic part at bank1 rear, the whole conduit pipe gets plugged up with burn deposits. Need to be replaced at once to restore effectiveness.
Ok, this time you described it, I can confirm my car doesn't act like as described before or after unplugging. I wonder if it has to do with ALT-LIN and the conjunction with your tune?
maybe maybe, no idea i just speculate what might be
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by KristiyanPetrov
maybe maybe, no idea i just speculate what might be
As mentioned before, you can plug the alternator back in. It's not like plugging the oil pump solenoid back in and risking a stuck solenoid. However, I have experienced a steady and consistent 14.1V with the ALT-LIN disconnected and I do not see how that could cause the shifting behavior. Then again, I know very little (i.e., nothing) about the logic used in these control modules.
As mentioned before, you can plug the alternator back in. It's not like plugging the oil pump solenoid back in and risking a stuck solenoid. However, I have experienced a steady and consistent 14.1V with the ALT-LIN disconnected and I do not see how that could cause the shifting behavior. Then again, I know very little (i.e., nothing) about the logic used in these control modules.
Perhaps he could still try the reboot sans the aux battery part since it is a capacitor, see if it does anything at all I guess better than nothing or temporarily flash it back to stock but keep ALT-LIN unplugged and see if the car acts normal again. That said, yours is also tuned and acts normal so I really don't know what it could be.
-- What gives ???
Let's concentrate on "idle control".
Idle is a special Rpm state tracked by ECU against various conditions: Load, Temp, A/C, ..., voltage?
> Engine Mechanicals vs. Engine Control...:
-- This ECU relearn idle control very well all by itself... why it does not is special.
It's time to go look at live PID datastream related to idle control.... See where these data can lead you.
-- Definitely don't blame "throttle body" Module unless active fault code. These TB are positioned with extreme precision!! Poor idle control is not caused by defective TB.
-- For good measure you could inspect TB for cleanliness at the threshold where butterfly plate meets its bore.
-- ECU logic is disliking something that cause poor idle control.
With that direction: you can read and decide to clean MAP/MAF sensors (some engines use both pressure and flow calculations). MAF are famous for being sensitive to cleanliness.
-- Intake plenum maybe swamped with oil overflowing out through the TB. 276-NA has an intake catch-can for that purpose.
Regardless of "moderate" blow-by... ECU should control idle Rpm. Not here!
> Stock voltage swings...
As suggested by JR and without sweating over ECU firmware compatibilities...
Go ahead try replugging ALT-LIN control and clear related ECU fault.
This will get you back in MOD-1 status.
Last edited by CaliBenzDriver; Apr 17, 2025 at 02:09 PM.
-- What gives ???
Let's concentrate on "idle control".
Idle is a special Rpm state tracked by ECU against various conditions: Load, Temp, A/C, ..., voltage?
> Engine Mechanicals vs. Engine Control...:
-- This ECU relearn idle control very well all by itself... why it does not is special.
It's time to go look at live PID datastream related to idle control.... See where these data can lead you.
-- Definitely don't blame "throttle body" Module unless active fault code. These TB are positioned with extreme precision!! Poor idle control is not caused by defective TB.
-- For good measure you could inspect TB for cleanliness at the threshold where butterfly plate meets its bore.
-- ECU logic is disliking something that cause poor idle control.
With that direction: you can read and decide to clean MAP/MAF sensors (some engines use both pressure and flow calculations). MAF are famous for being sensitive to cleanliness.
-- Intake plenum maybe swamped with oil overflowing out through the TB. 276-NA has an intake catch-can for that purpose.
Regardless of "moderate" blow-by... ECU should control idle Rpm. Not here!
> Stock voltage swings...
As suggested by JR and without sweating over ECU firmware compatibilities...
Go ahead try replugging ALT-LIN control and clear related ECU fault.
This will get you back in MOD-1 status.
during the PCV replacement i had cleaned the TB too (it wasn't that bad but since i had it in my hands decide to clean it), by clean map/maf sensor you mean with brake cleaner i guess Cali? would try it too when i go to change the oil
i might give a try to plug ALT will see, thanks all for contribution and feedback appreciate it guys
during the PCV replacement i had cleaned the TB too (it wasn't that bad but since i had it in my hands decide to clean it), by clean map/maf sensor you mean with brake cleaner i guess Cali? would try it too when i go to change the oil
i might give a try to plug ALT will see, thanks all for contribution and feedback appreciate it guys
during the PCV replacement i had cleaned the TB too (it wasn't that bad but since i had it in my hands decide to clean it), by clean map/maf sensor you mean with brake cleaner i guess Cali? would try it too when i go to change the oil
i might give a try to plug ALT will see, thanks all for contribution and feedback appreciate it guys
Something's doing it... right now we dont know exactly what's bugging your Engine Control module
Something's doing it... right now we dont know exactly what's bugging your Engine Control module
just found something from JR in another topic that our engine doesnt have MAF but only x2 MAP, will give a shot to remove it and clean it (just found out that is recommended MAP to be clean every 30-50k miles)
should i clean both of them? or just the one in the manifold
So I use my hand pump which can SUCK and do POSITIVE . See the gauge, left side is Vacuum or suction and right side is Positive pressure.
First you make sure you hand pump itself does not leak back and loose pressure. Block the test tube and see if pressure drop or not.
If pressure holds, that meant your hand pump is OK.
So my check valve is mild leaking, as you can see in the video.
If leak is bad, you loose turbo boost and will send boost to :
01. Fuel vapor system
02. Crancake PCV system.
Our turbo wastegate has metal flaps ( due to hot region ) to maintain boost/pressure, while the duo check-valve is plastic + rubber probably but they both do the same duty for maintaining boost.
You can't just buy the duo check valve, you must buy 1 set :
They are solid state electronics, no diaphragm in use.
-- Read your ECU MAP data before vs. after cleaning.
-- Then play around a bit ...
measure MAP pressure with PCV return pluged in vs. capped shut while reading idle rpm for variations.
++++ BACK TO SQUARE ONE:
If uncontrolled blow-by is proven as the cause then focus on cleaning piston rings if oval bores are not culprit.
will clean both of them then, unfortunately atm i can't make test before/after, so i have to rely on how i feel the car before/after unfortunately..
Originally Posted by JettaRed
Do NOT use brake cleaner, but MAF cleaner or electric contact cleaner if you are going to clean your MAPs. Brake cleaner may be too harsh.
yes i read that break cleaner is too strong for MAP sensor instead to find MAF/MAP cleaner spray after i spray it to leave it for 30min to 1h to dry itself, thanks for recommendation too
This is a POSITIVE pressure test, not vacuum. https://www.youtube.com/watch?v=cIhApK6chw4
So I use my hand pump which can SUCK and do POSITIVE . See the gauge, left side is Vacuum or suction and right side is Positive pressure.
First you make sure you hand pump itself does not leak back and loose pressure. Block the test tube and see if pressure drop or not.
If pressure holds, that meant your hand pump is OK.
So my check valve is mild leaking, as you can see in the video.
If leak is bad, you loose turbo boost and will send boost to :
01. Fuel vapor system
02. Crancake PCV system.
This duo check valve for our M276.8xx, its equivalent in a VW engine is a source of problem. https://youtu.be/hQEciqR1ST8
.
-------
Our turbo wastegate has metal flaps ( due to hot region ) to maintain boost/pressure, while the duo check-valve is plastic + rubber probably but they both do the same duty for maintaining boost.
You can't just buy the duo check valve, you must buy 1 set :
thanks for your inputs and help too, im now regretting that i did not buy this conduct to change preventive too (i do believe Cali told me to do that before i order the parts but i wasn't sure what is called conduct pipe at that time..) but ye.. when i visit the garage for my oil change will ask friend of mine to do this test for me and hopefully i can share results too..
back to boost, since my car shows boost if there's an issue with the boost as you stated shouldn't i see it on my dashboard (amg menu) i know too that there's no actual sensor in our engines to measure the boost too..
Boost is measured by the MAP at the intake manifold.
Anything above ambient pressure of your location is BOOST.
The higher the location, like a mountain, the lower the boost get as the air is thinner so less density.
Boost is measured by the MAP at the intake manifold.
Anything above ambient pressure of your location is BOOST.
The higher the location, like a mountain, the lower the boost get as the air is thinner so less density.
so if i see full boost measure on amg gauge can we say that boost is ok also im on sea lvl attitude
so if i see full boost measure on amg gauge can we say that boost is ok also im on sea lvl attitude
Yep, good thing you have boost gauge.
I think your engine has higher boost than mine which is only 0.8BAR.
But I do not know how your engine is mapped being a sportier version than mine, I mean as standard from MB.
My engine is set as comfort engine, thus the maximum turbo boost is not at redline but at approx 4,000-4,5000 RPM .
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