this morning I use the car on usual route, (everything back to stock settings) LTFT improved to 10%.




Later in the day I drove it on the highway, moderate traffic, around 50km and since its getting hotter ltft back to 14%. It seems LTFT getting worse during hot day




the engine temp is around 95 degrees, much hotter than the drive in the morning (is this normal?) It was in the highway about 60kph, with outside temp of 37 degrees.

 

95C is normal for MB now that you are seeing the truth via OBD. The analog gauge is a white liar and will show 90C.

I don't have much faith in your old front o2 sensor ever since it is reporting a good Lambda 0.99 vs emission test machine Lambda 1.06 and the excess oxygen showed that it is indeed lean.
.

BTW, that STFT and LTFT on your OBD gauge, that is Bank 2 ?

I am curious on your Tranny oil temperature, is that really the data or its "fabricated".
7G tranny does not produce tranny oil temp data for OBD.
When I used Torque Apps, the tranny temp oil data is wrong.

So how is Voltronic response on your o2 sensor claim ?

 

ah so its normal temp for MB then. good to know.

yeah the o2 sensors are old, but the LTFT data is very similar between them. I guess I can wait until voltronic to replace it. They are willing to responsible for it, and try to negotiate to 50%. I said no and just gave them the link on fcpeuro, just purchase it for me. Lets see their response next week.


the fuel trims data is for bank 1 (somehow they dont have the bank 2 data &#128564. For ATF temp it’s real, they can load custom PIDs. There’s dedicated folder for MB 7G tronic transmission, can display transmission slippage speed, input/output shaft rpm, torque etc.

Finally the trip for today ends, I use the car about 150km today, and LTFT data ends up at 14%. fuel consumption seems improved. I got 9km/litre for average speed of 40kph. Power wise also pretty good according to my butt dyno. No hesitation, misfiring, shaking etc. It runs great. To be honest it felt better (more responsive) after the catalytic cleaning, even with the pedal curve setting back to original. Did few WOTs after the toll gates too and its funn

BUT WHY MY LFTT IS SO BAD… So what next? I think smoke test is next

 

Did you do a smoke test yet?

 

OK lets do the Smoke Test, at my place. So we can raise the car +-50cm using my Quick Jack and see underneath for when and if there is a leak there and whatever others my eyes can spot.
Weekend is probably good for you yah ? Next weekend either 11-12th Oct. I will PM you soon.
If your wheel lug/bolt is using special key, bring the key too, just in case.

I must watch youtube how to best open up your intake manifold, I may want to read the COP firing waveforms and the COP is hidden under the intake manifold.
I got a new COP sensors from Rotkee Ukraine, I can read 6 COPs at once.... I did not try yet on my engine.
This way we can also see the combustion waveform, sort of.


It is so easy M272 air intake/filter box.....

 

this is on my next to do list, I have yet to find a workshop can do smoke test… perhaps I’ll do it at master @S-Prihadi place

I’ll came to whatever convenient time for you, if you only available on weekdays I’ll try to spare the time . To access COP/spark plug no intake manifold opening necessary, its a simple air filter box. No tools required. Your help is grealy appreciated.

 

Tesna,

Do me a favor. Can you measure the diameters of these 2 openings:


I need the OD only for this MAF sensor. OD = Outside Diameter




Measure ID and OD of this air intake pipe. ID = Inner Diameter.
If we use party balloon or my pump up balloon hole blocker, we use the ID, if we use rubber glove as cover, we use the OD.




For the smoke test, we need to plug off these "holes"

01. 2 of exhaust pipe.
Can you take photo of your actual exhaust pipe end shape ?
Mine is kinda oval and a I think party balloon can be used as plug or use a latex rubber gloves.




02. Depending on the smoke test stage, if we include the air filter housing, we then need to plug off one of the intake pipe and the other we use to inject the smoke into it.
This can tell also if the air filter box and the seal between it and the MAF sensor is leaking or not.


I need to make some sort of cap to cover MAF sensor diameter and inject smoke into there.
I hope latex surgical glove or thicker dish-washing latex glove is good enough.
If 1.5 liter Coca Cola plastic bottle can fit, I once ever used that as a cap too because its bottle is not flat dimension, but rather curvy, so we get variable ID size .


--------------


I am now reading about the Secondary Air Injection and I see potential air leak path from it if the AIR SHUT OFF VALVE does not close shut properly.
There are 2 of these valves....but in theory, if in stuck open mode.... it would leak exhaust gas out of engine into the electrical air pump and back into air filter box and engine suck exhaust air like an EGR.
However, if the air shut off valve design has some sort of venturi effect, it may be able to have fresh air sucked thru it and not only exhaust gas thru it.
This is the unit :
This is a case of a stuck open AIR SHUT OFF VALVE
.


I only have 3 of these, pump-up balloon for blocking holes.


And it can't be pumped too fat, it is very thick, unlike party balloon....but it is tough.


------------------


One bad news for M272 owners.

The intake manifold bushings can leak. Bushings are like bearing for anything which can spin.
The shaft + bushing does spin left and right inside a vessel with suction pressure easy 0.5 atmosphere or 7 PSI vacuum, so wear and tear over time on the bushing can cause small gap opening


Go to 1:21 minute



Go to 8:24 minute



That in red circle is the item which has the bushing. There are 3 of these type.





These 3 can spin between reduced atmosphere of in intake manifold and the external ambient air full atmospheric pressure, so bushing they must have.
This is a risky design for longevity. unless a proper air/oil seal is used, like say crankshaft or water pump seal.

 

@S-Prihadi ok here we go,

start with the air intake hole, 73.5mm ID.. OD just add 2mm ish.

air intake


the MAF is not round, its oval. hard to get measurement there

ID of the longest part is 89mm and the shorterst is 85mm?

MAF1

MAF2

Since the mesh metal filter is loose when I took of the air filter cover I did not install it back. (afraid it might get sucked into engine). Tried to install it back but seems loose.






and now the hard part is the exhaust, previous owner replace with E63 bumpers, side skirts, including the exhaust tips, so there are total 4 exhaust tips :O


The intake manifold, this has been on my wishlist for a while. there's someone selling it on tokopedia, for 5.5 million IDR. Claimed original. Should I go for it? https://www.tokopedia.com/europartge...hid%3D17187536 this is also my top suspect since the LTFT on bank 1 and bank 2 is different. However, I really want to confirm it with smoke test before I threw more money on parts lol

The air shutoff valve is the EGR right? that one just cleaned a month ago (when doing the injector calibration and cleaning) but I'll check for exhaust leak from that hose anyway. But on idle is it supposed to do that? EGR enabed during idle/low load, then under load/heavy load then EGR is off. I'm not sure.

I can hear the airpump working for a minute or so during cold start, man its noisy.

 

Good info thanks.
"previous owner replace with E63 bumpers, side skirts, including the exhaust tips, so there are total 4 exhaust tips "

By sight, can you see if the after-market AMG 63 exhaust diffuser tip, its middle partition blocking entry for my pump-up balloon into exhaust pipe or not ?
Mine is single opening diffuser tip.


.



.
If your final exhaust pipe is positioned like mine, I think it will be on the outer window of the twin window diffuser. I mean the center partition does not really block us pushing the balloon into exhaust pipe.





If the type used is like below, dang, that is like a real two holes unit






Size perspective of the Autool balloon.


As long as the middle partition of the AMG 63 exhaust diffuser is not blocking us pushing into the real exhaust pipe the balloon, we are good.
Of course worse come to worse we can use rags...stuff them rags.

The tighter the sealing , the better if for smoke kit, because we want about 0.5 PSI positive smoke pressure to exit out of small holes.
My smoke machine can do 30 PSI, so it can send smoke into narrow passage and super small leak even at simply 1 - 2 PSI.

The rest of the "holes" I am no more worried now that you gave me the measurement.
This gloves , 2 types should do the job as injection adapter at MAF.
I need to have such supplies ready too....




Awaits your AMG exhaust tip inspection......

 

I forgot :
Your car has Secondary Air Injection ( SAI )and that is not an EGR.
SAI inject fresh air into exhaust manifold, not intake manifold. This injection is before o2 sensor, so it can make o2 sensor read lean.
An EGR divert exhaust gas, back into exhaust manifold.
.

This is from M271 EVO, E200 or C200 tech info and if foreign market, not Indo market, same concept on M272 for SAI.




.

 

Tesna wrote :
The intake manifold, this has been on my wishlist for a while. there's someone selling it on tokopedia, for 5.5 million IDR. Claimed original.
Should I go for it?https://www.tokopedia.com/europartge...hid%3D17187536

Cant be that cheap.

US$860 at FCP Euro
It is US$650 best price and reman/rebuilt unit : https://www.mbpartsexpress.com/searc...tr=A2721402401

Alternative is Pierburg one : https://www.fcpeuro.com/products/mer...fold-700246330
https://www.tokopedia.com/pbauto/int...h&refined=true
I think the OE is Pierburg.

Also that seller price for M276 engine oil filter at Rp75K / US$5.00 is a fake for sure 1,000%
Doing business since 2024 ...fishy.
Even the one who sold me the timing chain tensioner he claimed it is genuine...but fake.
I notice all the location of these sellers are East Jakarta...I wonder why, maybe close to Tanjung Priok warehouse hahahaha

 

@S-Prihadi my exhaust is exactly as:

> If the type used is like below, dang, that is like a real two holes unit




even when doing exhaust emissions test its quite hard to insert the probe lol.

I think the same valve also used for EGR system (this also connected to the air pump)

thanks for the intake manifold link, they only got 1 in stock :O should I order one

This morning I started to obsessively watch the fuel trims number. What I notice is the STFT started going high positive (+16%) when decelerating, then when it goes near complete stop then idle STFT goes high negative :O what does this means. After 30 secs of idle or so then STFT goes to 0%. Is it because when decelerating vacuum is at the highest point? higher than idle? Here's the video



Yesterday when measuring the MAF size, I found on the oil separator (located in top of bank 2) leaking oils. https://www.fcpeuro.com/products/mer...tor-2720160134. I cleaned up the oils, then after using the car this morning I check it again and yes its leaking oil. This part is the only FEBI part (they dont have the mercedes one) maybe the mechanic did not clean the surface good enough, or FEBI maybe just bad.

Btw, can you recommend me a tool set to opening mercedes bolt I might want to clean it myself or install back the original one

https://www.tokopedia.com/bmw-sparep...whid%3D2413709

or this one https://www.tokopedia.com/coronatekn...hid%3D11160293

 

Aha, the utube guy, he call it EGR/Air Shut Off Valve. that is actually part of the Secondary Air Injection system.

I was studying M272 set up via EPC and WIS last night.





-----------------------------

Tesna wrote in green:
This morning I started to obsessively watch the fuel trims number. What I notice is the STFT started going high positive (+16%) when decelerating, then when it goes near complete stop then idle STFT goes high negative :O what does this means. After 30 secs of idle or so then STFT goes to 0%. Is it because when decelerating vacuum is at the highest point? higher than idle?

Good thing you mention this .

Something is not right.

I added time code to your video in seconds.


.



.




What stood out is your Manifold Pressure sensor is crazy slow, like no respond.
Your Fuel Trim ST is also slow, very slow.
So above 3 screen capture of your OBD gauge, represent about 7.x seconds of logging.
Let's assume you OBD gauge is fast enough and the data is as what ECM pumps out.


Here is my log for 6 seconds.



Pay attention to Manifold Absolute Pressure ( MAP ). on mine and yours. Ignore the BOOST which your NA engine wont have. Just look at the negative MAP data.
MAP should be very dynamic, because we can see your MAF ( Mass Air Flow sensor ) grams per second is very dynamic, which indicates airflow and that means throttle body opening.

My engine is purely MAP based for engine breathing data, yours has MAP and MAF.


.



.
Your MAP looks like similar unit to M271.8 EVO



Do you have MAP/MAF cleaner like this one by CRC : https://www.tokopedia.com/virlie/crc...26src%3Dsearch

Your MAP uses extension hose and not direct feed to INTAKE MANIFOLD.
So cleaning it, you must also clean the hose entire length.

It can also be "defective" in a slow way, not totally dead.



--------------------------------------------------------------


Simple job on MB engine with Torx, you do not want 1/2" drive, it is too big.....that Tekiro set.

Get this one and I hope the dimension is accurate. Some low cost tools dimension tolerance at times not so good.
https://www.tokopedia.com/handyman/3...lse&src=topads
This is mix 1/4" drive and 3/8" drive. Good for tight access.

Get these rachets and extension and 1/4" to 3/8" drive adapter I indicated in red ( 1/4" family ) and pink ( 3/8" family ).





Sometimes you need these , when you do more work.

1 below is racheting type. 2 is normal one.




Get SATA brand in Toped for L shape Torx, it is good enough and low cost.
I choose this German Wiha is because of the ball shape on one end, sometimes ball shape can do well if angled.




------------------------



Can you bring rags to block those 4 exhaust holes ?
Perhaps those cheap thin towels, so we can plug them holes
First we will try with Party Balloon.... he he he.

 

@S-Prihadi ok I’ll try to clean MAP. Or maybe just replace it.

Btw today I just do WOT and guess what CEL is on 🫠

the irony is when I have problem with positive fuel trim I have cel system too rich



what is going on

 

HHmmmm..... interesting.
Can you go deeper into the Launch DTC to see more details on the event ?
We call it Freeze Frame data.

If both banks reported RICH, it is probably really rich.
This part I am also wondering, which sensors are deemed as correct, when and if front o2 sensors is opposite value of rear o2 sensors ?
Some I read , that the CAT gets high priority, thus rear o2 sensors can be the one to trust at certain condition....but it all depends on how the ECM is programmed.


This is a BMW engine video below, where the front o2 sensor read as RICH, while the rear o2 sensors read as LEAN and fuel trim uses front o2 sensors as data to make decision.
The problem is the front o2 sensors is faulty and reading FALSE RICH . So this BMW is using front o2 sensor for mixture but since it has also DTC for rear o2 sensors, it can raise the DTC of rear o2 as LEAN.
I am hoping your M272 ECM can tell you which o2 sensor is the RICH DTC coming from ?


.


Try log idling while showing both front o2 and rear o2 sensors reading.
Also snap-throttle a bit to see how o2 response : should sudden rich and then sudden lean.

That weird MAP sensor, I do not know how your ECM take its data as part of the AFR calculation, along with MAF....who is the Boss, MAF or MAP ?

Usually in a MAF only engine, defective or going bad MAF can report wrong air input and cause either lean or rich as long as o2 sensors are accurate.

Now we have a plausible front o2 sensors too, I mean the old ones now in use...dugghhhh.


I do not have experience with MAF sensor and what is the typical M272 grams per second of air at idling and at X high RPM.
There are rule of thumbs based on engine's displacement because of the 1:14.7 AFR rule and the Volumetric Efficiency (VE) of the said engine, accuracy about 20% variable I think.
If the engine is healthy, we can calculate the VE and keep it as reference for future use.

 

@S-Prihadi I think when the engine is under load, the vacuum leak effect is gone and STFT was like OH NO IT IS TOO RICH REDUCE FUEL!!! . Then when decelerating vacuum leak effect is back again, and engine decide OH NO NEED MORE FUEL... MAYBE... i dunno. I'm not sure also why it only trigger CEL by today. I often do WOT after toll gate payment

I can't check freeze frame data on the DTC yet, because I left the car in the workshop. I immediately go to the workshop after I saw the CEL ) Now the car is undergoing change the whole intake assembly (with pierburg one). Should I replace the MAP also? or also the MAF? at least if the fuel trims its not improving we can cross out the intake assembly as the source of vacuum leaks... but yeah I think its triggered by STFT going 18+ and 18- by light accelerating and decelerating. Perhaps WOT figures way past that.

o2 sensors yeah i know its the old one, but the LTFT figures is very similar to the new bosch one. Until the replacement arrives I think still ok to use the o2 sensors. Btw, voltronic finally agree to replace the whole 1 sensor cost, however I'm still arguing to also cover the shipping + import duty cost. So far they only cover the price listed in FCP euro without shipping and import duty.

 

Stingy azz Voltronic.
That means you will loose out of pocket US$35 for shipping plus 25% of it to import tax of CIF, approx US$44
And 25% of the o2 sensor cost for its import duty or US$142 x 25% = US$36
and Rp200K ish for Fed-Ex local charge.


If you can replace the MAP it will be good
MAF perhaps later, best also get genuine spark plug from MB Mercindo at Toped.

MAF is quite a delicate calibrated sensor. MB genuine one I think its expensive.
Will do comparison one from Bosch later, we try to get the correct Bosch-MB equivalent P/N first.

 

Ok got the whole intake manifold assembly replaced, then also the MAF, MAP. That clear up the codes, the value of the STFT also back to normal, always closer to 0, no more sudden high negative/positive when accelerating/decelerating. WOT also not trigger CEL anymore. This is weird this happen very suddenly.



new gasket included


The LTFT is NOT improving tho , I guess I still need @S-Prihadi help to do the smoke test. I'm at my wits end. I havent reset my adaptation values tho, as my experience LFTF quick updating after a reset. At least I can cross out intake manifold as the source of vacuum leak...........

 

Remember your front o2 sensors are still old one.
We will smoke test it, target is PCV system, Fuel EVAP system and the Secondary Air Injection.

I hope the MAP and MAF was not having accelerated aging due to the chemical used by Voltronic....anyway its by-gone now.
So the MAP is by Bosch ? How about the MAF ?

 

I have this image of someone pretending to throw coins into the toll gate basket and taking off WOT before getting caught. (Of course, that was back in the day when the toll was a quarter or 35¢.)

 

and maybe the exhaust? whole PCV system was just replaced very recently, but lets check anywayy. I havent touch the fuel EVAP and secondary air injection.

the MAP is original MB (claimed), the MAF is bosch. I replaced MAF because the metal mesh thingy on the original maf somehow become loose,


MAP, made in japan!?!?

intake manifold

MAF

MAF

old intake. this was cleaned one month ago. but it seems already dirty especially the part the connection to the inside (the round one)




yeah we still use gates here I wonder when will they implement payment without stopping thingy here

 

I just tested my smoke machine , all good.
The baby oil will need to be renewed, the one in the reservoir. It got yellow-brown from heating up.
Supposedly it has to be renewed before each test...LOL, I forgot about that after last use/test.

I was wondering if I can next time use smoker's Vape liquid with nice smell.... baby oil smoke does not smell good and it has oily trace, it is pure mineral oil after all.





.





.



--------------------





I think temperature wise vape liquid is within the temperature range of Johnson Baby oil .....if we use it for smoke generator

 

THANK GOODNESS!!! I was imagining the worse.

But, why the hell would you rub petroleum on babies?

 

, that would be KY

 

I was born in Kentucky.