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Finally I took the car for a long trip. (400km in one day trip!) What I noticed is when the engine under heavy load on longer period (eg long uphill on the highway ), the LTFT tend to improve, and for the first time ever the LTFT goes to 7-ish %! Usually the best I got is 8.5%. And that during a HOT day too, so I can wrote off high temp as the cause of higher LTFT. However, when stuck in traffic then it goes bad quicky (reaching 14%) When cruising on flat highway on cruise control set at 100kph, LTFT usually on 8-9%.
Fuel consumption is quite good too, on heavy foot I get average 9 ishL/100km on the highway. perhaps if I baby it can get better. Engine power and response also very good, no pinging/misfiring, no hesitation, no noticeable problem what so ever.
So do I need to close the book of getting LTFT closer to 0%? or do I need to check on another things? seeing LTFT got improved when the engine under higher load, do I still have vacuum leak somewhere? or its not vacuum leak? what else should I check?
A lot of good ground got covered and known issues reworked to extend your engine life.
Yet you still have a lean engine that ECU is handing more gas to...So the solution is likely in something that was not delt with, right?
-- Do you know if anything was sayed or done about CAMSHAFT TIMINGS?
-- I am wondering about your limp TENSIONERS messing exact timing on a port injected non-GDI engine.
-- Perhaps you an attache an MP3 of cold start sequence, fast idle to normal idle.
ECU data stream may show VVT work done to dial camshaft position.
No data PID is gonna be screaming, just couple items pointing to.... timings correction??
Perhaps you want to screen-cap. all ECU data stream available on your scanner... we can pick from it.
Last edited by CaliBenzDriver; Oct 27, 2024 at 01:04 PM.
Generally, any value between +/- 10% is considered "normal". Going over +/- 25% will trigger a fault and CEL. What that means is that the ECU is able to control the amount of fuel to keep the A/F mixture Stoichiometric and the car is consider operating within acceptable limits.
As long as you can pass your emissions test and there a no DTCs, I'd put the Lufi away or change the display to not show LTFT.
Indeed, it may be a good idea. Regarding the emission test, I had a hunch that my cat might have partially disintegrated, as there is a rattling noise from the rear resonator on the bank 1 side.. This can potentially lead to high HC, but it should not elevate the LTFT. Fortunately, there have been no cat-related DTC (yet) despite the installation of a new downstream O2 sensor.
Originally Posted by CaliBenzDriver
A lot of good ground got covered and known issues reworked to extend your engine life.
Yet you still have a lean engine that ECU is handing more gas to...So the solution is likely in something that was not delt with, right?
-- Do you know if anything was sayed or done about CAMSHAFT TIMINGS?
-- I am wondering about your limp TENSIONERS messing exact timing on a port injected non-GDI engine.
-- Perhaps you an attache an MP3 of cold start sequence, fast idle to normal idle.
ECU data stream may show VVT work done to dial camshaft position.
No data PID is gonna be screaming, just couple items pointing to.... timings correction??
Perhaps you want to screen-cap. all ECU data stream available on your scanner... we can pick from it.
As of now, I have not yet touched the anything related to camshaft timings. However, based on the data from Xentry, all parameters appear to be within acceptable limits (all green). Upon cold start, there is a noticeable rattling or tapping noise that persists for approximately 1-2 seconds. Is this a potential indication of an issue? I had previously owned a vehicle that exhibited similar noise, leading me to believe that it may be a normal occurrence due to insufficient oil flow to all areas during those initial start. I'll try to record video/sound later. I intend to record live data related to timing and hope that my launch scanner will provide access to this information.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
I just posted this in another thread. I don't know if it applies to the M272 engine, though.
There is a momentary rattle when starting the engine cold. This is attributed to insufficient oil pressure on cold start because the engine oil has drain back into the oil pan overnight. Chain tensioners are hydraulic, and the lack of oil pressure on startup allows the timing chains to be loose for a few seconds during which the chains slap against the tensioning rails. Over time, the chains cause premature wear of the rails to the point of possible chain skip.
Mercedes has addressed this by using a one-way check valve with updated tensioners to reduce or eliminate the drain-down of oil. The fix can be retrofitted to older engines, but many times the damage of excess wear has already occurred.
Well, thanks @JettaRed for the insight, it seems timing chain tensioners is on my next to do list as this rattles already. What else to be changed? the chain? the chain guide? is this the correct one? https://www.fcpeuro.com/products/mer...hain-kit-30328
I would go in for minimum the TENSIONERS (check valves) then inspect intake VVT Gear locks and replace at that time or weeks later when parts are delivered to Jakarta.
The old tensioners provide camshaft looseness with idle low pressure. That screws up exact timings picked up by CPS and acted upon ECU.
MB uses limp tensioners to save frictions... with reduced oil available tension is marginal as pressure leaks out anyways.
As yensioners become unable to hold pressure, the camshafts are able to jerk forward during rotation by using chain slack, unopposed.
Post a warm idle sound clip (without A/C running!!)... the engine can tell us if it needs tensioners.
Last edited by CaliBenzDriver; Oct 29, 2024 at 12:47 AM.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by tesna
Well, thanks @JettaRed for the insight, it seems timing chain tensioners is on my next to do list as this rattles already. What else to be changed? the chain? the chain guide? is this the correct one? https://www.fcpeuro.com/products/mer...hain-kit-30328
@S-Prihadi would be better to ask since he has seen your car and would likely know if he thought you were having tensioner problems. The problem was primarily with the 157, 276, and 278 engines. However, that doesn't mean the tensioners on your engine haven't gotten tired.
Tesna engine when started a few times at my place was OK , I mean free of VVT rattle, granted it was never from zero COLD.
If bad VVT, even mild warm like 60C, it would rattle.
I did not inspect his VVT correction factor as per Xentry, I did cylinder 1 mechanical compression test and re-torqued all 6 spark plugs because the CAT cleaner service boys ( Voltronic ) did not torque them properly.
I also did all 6 cylinder ignition waveform....all OK.
If at zero COLD start ( 30 Celsius ), 1-2 second super mild extra sound from engine its OK.
VVT rattle is crazy loud, as per my friend's C200 M271.8 EVO engine.
-------------
I believe Tesna engine on purpose was set by MB Indonesia as LEAN.
It would be good to test and change it to Slight Enriched like mine.
His last trip to Bandung City gets good decent lean at +7% LTFT only and not high +10-15%, I would think it is because he had to apply lots of throttle to climb the altitude difference and overtake other cars.
During deeper throttle, his engine will be in OPEN LOOP and RICH, based on the fueling and ignition MAP stored in his ECM and not based on the front Lambda sensors.
So more fuel injected. Thus the LTFT gets better, not too lean.
During traffic creeping speed, his throttle will be super light and that is Close Loop and need extra fuel too, but based on front Lambda values....hence it goes into the LTFT database.
@S-Prihadi yes it only rattles at cold start, after sitting for the whole night. Perhaps change the tensioner only as I look up changing the timing chain and its guide is a big job :O. The tensioner seems not too expensive. However, I don't think I can fully trust my usual indie mechanic to do it lol. This one I need obtain the correct procedure and making sure the mechanic follow the procedure. (no I'm not capable of DIY this job lol)
btw, my other/previous car also sounds similar, rattles at cold start. I thought it was hydraulic lash adjusters or something. Perhaps I really need to record it. This morning I forgot do record
As changing the fuel setting to slightly rich, perhaps I'll try it. Btw, replacement o2 sensor from fcpeuro should arrive within few days, will be back on new sensors soon!
OK Bro.... we wait for new front o2 sensors installation and then the fuel setting to SLIGHT ENRICHED.
If timing tensioner only, 2 pcs top side ones, its not too difficult a job and it will be good to also re-seal that small VVT window, as it leaks a tiny bit of oil usually.
Genuine MB tensioner is not expensive. Under Rp2 mil each from Dipo, I bought all 3 last year.
3rd tensioner for oil pump, no need to worry about it and that is a BIG JOB.
Timing chain is a big job and no need at your mileage.
OK Bro.... we wait for new front o2 sensors installation and then the fuel setting to SLIGHT ENRICHED.
If timing tensioner only, 2 pcs top side ones, its not too difficult a job and it will be good to also re-seal that small VVT window, as it leaks a tiny bit of oil usually.
Genuine MB tensioner is not expensive. Under Rp2 mil each from Dipo, I bought all 3 last year.
3rd tensioner for oil pump, no need to worry about it and that is a BIG JOB.
Timing chain is a big job and no need at your mileage.
as requested by @CaliBenzDriver today I record engine data, particularly on camshaft angle record. (finally I figure out to do screenshot on the lauunch )
What I noticed is, the left sensor of exhaust cam is very active during driving (this is driving in morning traffic jam, so very slow speed and stop and go traffic, so light throttle, no wot), whereas the right bank stays flat the whole time (approx 30 min or so) at -20 degrees.
The intake camshaft sensors, both bank stays flat for the whole time.
I guess at least something wrong with CPS? or perhaps the camshaft adjuster magnet? what do you guys think? But I'm confused why it does not throw DTCs....
I hope its the scanner. I was recording a lot of PIDs available. I'll try again to record only the camshaft angle later.
the aftermarket scanner coverage has limits... It's good for some things, just not everything!
Most ppl don't use half the functions you did.
You can reboot your whole chassis computers as much as twice a month. Some modules become lazy at transacting synchronous data near realtime speed.
A fresh chassis reboot will help temporarily run network modules on their best behaviors.
For timing data in graphic mode, the baby launch will be too slow.
Need Xentry, the spec like the one from Benz NInja. Even Xentry-Passthru is not able to log VVT properly, because it is also too slow.
Don't worry Mas Tesna, your timing should be OK, othewise the DTC will appear.
it seems the scanner, if I only log only the camshaft sensors the data is there. The intake is not much change, perhaps because it is in slow crawling traffic. The exhaust cam however so much change
When I do not apply throttle aka coasting, my exhaust VVT is at -23 to -25 degrees and intake will be approx +33 degrees.
But they will be jumping like monkeys as soon as the throttle input changes.
Yours is almost a 1 minute log, the Exhaust seems too flat line. I think the Launch can't handle the data volume.
Xentry Ben-Ninja version is minimum 4Hz, usually 7Hz if for VVT logging 9 channels including RPM and Target and Actual degrees of all 4 VVTs.
This morning traffic its a bit clear, so a lot of movement in the intake side. Of course xentry is so much better, but for now xenty is way above my skill level lol. It seems launch has limitation on how many PIDs to monitor. If I limit the PID seems works ok. At least bank 1 vs bank 2 seems to be in sync.
Master Surya and Mas Tesna:
you didn't give up and got rewarded with what you wanted: cam data plots
Somehow I managed to spot something that looks a bit odd this is exhaust camshafts positioning this exhaust plunge look weird! both banks appear to be tracking perfectly
can we get both exhaust cam b1+b2 with a sweep up ramp from idle to 2500Rpm
then same with both intake only
Last edited by CaliBenzDriver; Oct 31, 2024 at 01:33 AM.
If those baby Launch log is accurate, what most important to see is commanded degree vs actual degree, error rate 1 to 1.5 degree acceptable.
Why it took a plunge, if that is the commanded, well that is what the ECM wants.
If those baby Launch log is accurate, what most important to see is commanded degree vs actual degree, error rate 1 to 1.5 degree acceptable.
Why it took a plunge, if that is the commanded, well that is what the ECM wants.
Yes, good question!
Are we looking at ECU commanded
or camshaft position sensors <<----- want that
We need to trust we are looking at accurate camshafts timings.
The goal to get valid data.
Last edited by CaliBenzDriver; Oct 31, 2024 at 01:44 AM.
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