wonkaa

hello everyone, i am after some advice and help!

i have a 2005 e350 sedan the 3.5L V6 model
just hit 85000 KMS

it is a japanese import grade 4 and i have owned for 1 year exactly having two services and a transmission fluid change in the first 3 months of ownership.

i had the 2nd service done last thursday, picked up the car around 3pm drove a few kms and noticed that the fuel was on 2 bars and fuel empty light was on, so went to a BP petrol station and filled up about 20L with Unleaded 98 (usually use 98 or 95). Kept driving maybe 20-30kms and the Check Engine Light came on around 5.30pm.

Thought it was a loose fuel cap or something as ive never had a problem before so drove home, checked cap and light was still on. Slept on it.

Woke up friday took it straight back to the service centre and told them the story, they hooked in up, scanned it, and had some codes (not sure what)
cleared the codes, re-did the "Adaptations" ??? and drove around a few times brought it back, re checked the figures and said it was back within range so should be ok. Went straight home, didnt use car until next day.

Saturday: drove out in the morning and about 20 mins later the light came on again. sigh...

service centre didnt have time until today (wednesday) dropped the car off at 8am, and went to check at 3pm and they said the car is running rich!

not too sure what the problem is, they said something about thermostat, airflow meter, fuel pump, oil pressure blah blah

now, does any1 know what is going on? why cant they find the problem? its been like 7 hours???

they just did a full oil service as part of a mechanical waranty requirement, and this happens the very next day.

please help with any knowledge, i dont want to be taken for a ride for like 10 hours of labour pay and $1000 in parts.

Thanks

From New Zealand

Plutoe

Well the good news is that ignorance breeds ignorance---based on your opus I would say that the the service center you visit doesn't know the difference between a lamb shank and a pork belly and to have them correctly diagnose your issue would be next to impossible!!

I am not going to spend loads of time explaining to you about mixture adaption(long and short term) when you obviously have the time to learn that yourself.

But for sure you need someone who does and also has the DAS Xentry diagnostic equipment to quickly determine which injector is faulty or which O2 sensor is incorrectly telling the ECU to enrich the mixture to maintain the designed and correct air/fuel ratio.

Don't ask me what or where---you have a search button on your phone or computer---use it!!

wonkaa

Thanks for the reply.. very confusing. I take that its a injector or o2 sensor from what youve said.. will see what they say tmr and posf details... sigh no professionals here.. they r supposedly specialists too..

vettdvr

YOU must get the codes. They will tell you O2, Injector, MAF, or other issues.

wonkaa

So i got the car back today, heres what i found out.

Not sure what the code numbers are but something about left bank right bank? And something about adaptations. Normal is 0. Range is -4 to 4 and mines at -6?

So i had a loose bolt in the exhaust flange (right side) just behind the cats. (Between the muffler and cats)
They tightened that up on thursday.

Is it possible that due to the loss of pressure caused by the loose exhaust joinery, the engine may have been feeding extra fuel to conpensate? That or me filling up petrol is the only variable in this equation..

The owner of the service centre said he thinks its most likely the injectors but they need to open it up and check (2 hours of labour).

Another thing we noticed is that the fuel consumption seems very high.

Long term average was 6.9km/l. On drives im getting between 8-10km/l it seems?

He said he checked the pressure in fuel pump and it was losing some but not too bad that it would cause a check engine light. He also checked the pressure in the engine? Injector bay? (Not sure) and said it was dropping as well. (Maybe this is why he thinks its injectors?)
He reckons maybe contaminated fuel may be the cause for broken injectors.

He reckons its not o2 or maf sensors.

Anyway thats my findings so far. Got the car back and havent paid anything yet. Thinking to go back next week to check the injectors?

What do yall think?

Thanks
Kyu

Plutoe

Find a shop that works on MB's!!

wonkaa

Well thats the thing, they are a mercedes and bmw specialist. Owner has 30 yrs experience some at our local mb dealer and one of his staff was at south africa mb for like 15 yrs too. I got good referral to go there.

Should i go to the dealer stealers?

Plutoe

If that is the case then you are not communicating with your shop and the shop is not communicating with you and you are not communicating with us----simply ask them to provide you with a copy of the DAS Xentry "quick test" and post. Don't come back and tell us they don't know what that is!!

wonkaa

Ok i will do that first thing monday.

I just googled DAS Xentry and saw some photos on google images and it looks the same as the software they were using.

Sample image from google


Basically they told me the error codes came up and it was something something left and right bank

And something adaptations something..

Sorry its all new to me and i couldnt remember it word for word..

They have cleared all fault codes and car is back with me now. I havent had a chance to drive it much but CEL hasnt come back on yet.

Cheers for the detailed replies. Seems like i joined the right forum.

vettdvr

It really doesn't matter the brand of car when using closed loop fuel injection for problem solving. Codes are really important. Now to answer the question how can a loose bolt cause a rich mixture.

The close loop uses TWO O2 sensors on each cat converter, one before and one behind. IF the one before is losing exhaust before the sensor it won't read correctly and can possibly read lean. The close loop system will get a lean signal to the control module and send a signal to the fuel injectors to change the pulse open time which will enrichen fuel. Notice this is how it can work but may not be what is happening to yours.

IF you tighten the bolt, sent proper air to the sensor the system can correct IF that is your only issue.

So Yes a loose bolt can cause a problem but only driving will determine if it corrects your problem.

wonkaa

I called the guys that had the car before and they told me the error was:

Self adaptation mixture lean both left and right side.

Should i find another mechanic to recheck?

Edit: just so we r clear. The car was "fine" with the loose bolt. (Fine as in no error warnings. Maybe not fine but no sensors going off) the check engine light came on after bolt was tightened. Which leads me to think that if possible the car is now confused and needs to re learn how much fuel to inject?

I duno.. so confused.

Ive filled up with 98 octain and been driving short and longish trips.

Ive done about 150kms so far and the fuel bar is just under the 3/4 mark. Seems reasonable for now?

I expect 6-700 km to a tank of fuel? Is that about right? Mixed city and motorway driving

wonkaa

Just got the car back from the local mb dealer service centre.

Check engine light is caused by the.....

Air mass sensor

They quoted roughly 1400 nzd for the part from germany

What do yall think?

Plutoe

The good news is that now you have reputable information to search for and install the part yourself!!

To define the part---------What is the VIN!!

wonkaa

Vin : WDB2110562A764091

Is the mass air sensor same as airflow metre or MAF?

Sorry for the noobness but my search for mass air sensor comes up with like a $100 part and thats waaaaaay cheaper than 1400..

vettdvr

Air Mass Sensor............Mass Air Flow,, both preform same function but which brand of car and type determine the name.

They both measure the volume of air entering the engine, send a signal to the computer to vary the timing pulse that determines how long the injectors stay open for a given fuel pressure to control fuel / air ratio.

It is very possible this is the cause as I suggested in earlier post for your issue.

I don't know how much 1400 nzd is but if it is over $400 US dollars you are probably paying way too much. Find one from a reputable supplier on line.

Plutoe

YES

the current part is 273 094 09 48 lists for 444 USD Ex works(do not accept a different part number)
also suggest two gaskets 273 141 97 80

Go to one of our sponsors web site surely they export parts make sure they list the part as used(save you on duty)

wonkaa

1400nzd is about 1200 usd. There is a 15 percent tax in newzealand but he said that he could do 15-20% discount. So yea. I really cant understand how its soooo expensive.

Thanks for thr part number
I will look for that part and TWO? of the gaskets?

Also i was wondering is it a simple plug in job or do i need to go re scan and re learn the adaptations or something?

Thanks so much for the help.


Edit:

Just checked out autohaus AZ and searched the part number and its $120

Also checked pelican parts and got one for $121 and another for $455.

Plutoe

Ideally, you would clear the fault, then install the new MAF then the ECU receives the correct info and away you go! However not clearing the fault and installing the MAF will take about 5/7 drive cycles to turn off the CEL!!

Audi Junkie

Loose airbox