E350CGI, 2010, Lean Errors Help please!!

[Popell]

Merry Christmas all, hopefully someone may be able to offer some advice.
Situation: 2010 E350 CGI Petrol, 95k miles
Historically (over past 35k miles) I got 26.7mpg
Over last poss 700 miles, average dropped to 26.4! so a big drop, struggle to get over 24 mpg driving like a pussy but on none main roads
On a couple of occasions, got management light up with codes P0171 and 174, Lean on banks 1 and 2.
Freeze data showed them to occur at idle 540 rpm. I dont recall seeing any other than idel conditions.
I have a basic scanner which shows Fuel trims both sides and O2 votages for all 4 sensors.

Checked for vac leaks with propane around back of the engine near MAF, no change on ST fuel trims.
Chucking propane around air intakes does produce a change.

Fuel trims now all negative but single figures, they had been double figure positive!

I have tried cleaning MAF (but only had brake cleaner on hand)
I have replaced all plugs - not really because I thought it was a cause but probably needed doing.
I have checked for vac leaks in engine bay and around brake servo.
I can read MAP which is 10-12 in.HG on idle and light throttle, down to 5-7 on over run (hoping this confirms no vac leak)
One mech mentioned variable valve mechanism (didn't know if I had one of those!) and reading up on here and elsewhere, the EGR, don't know what this looks like or if I have one.
Marcedes parts guy thought poss clogged fuel filter due to using some supermarket fuel.

I have run through Wynns injector cleaner (twice) and filled with V power from Shell.

Considering replacing MAF but the merc OEM is rather fruity at £231+vat! Bosch available for considerably less(£95), Pierburg for slightly less(£175)

Any of you have any advice re cause or solution?

 

[Blobcat]

Is it getting to temperature?

 

[Conor]

Hi Popell

I have the same motor as you, and had the same problems. I changed the PCV valve and all went away.

Unfortunately changing the PCV valve is very much a pain in the ass.

Here is some info on me changing mine.

https://forums.mercedesclub.org.uk/index.php?threads/w-s212-bulkhead-removal.184724/

Also, I believe there is an EGR in that car.. see my annotated exhaust diagram.

 

[Popell]

Is it getting to temperature?

Thanks Blobcat, yep gets up to temp well.

 

[Popell]

Hi Popell

I have the same motor as you, and had the same problems. I changed the PCV valve and all went away.

Unfortunately changing the PCV valve is very much a pain in the ass.

Here is some info on me changing mine.

https://forums.mercedesclub.org.uk/index.php?threads/w-s212-bulkhead-removal.184724/

Also, I believe there is an EGR in that car.. see my annotated exhaust diagram.

View attachment 64429

Thanks Conor, I think I read your account of the difficult task of changing out that bit, secretly hoping it’s not the course I have to take!
I’ll re-read it, in the meantime I don’t know what the function of the PVC is.
So the thinking is away from the MAF?

 

[Conor]

So I can't really advise on diagnosing or troubleshooting, but I will say that the PCV valve is something that does get changed a lot on cars.

When I was originally discussing issues of lean codes, I was steered towards the MAF. I opted to change out the PCV system (separator and hoses) as they are known to sometimes leak also.

I can't advise on moving thoughts away from MAF, but all I can say is I haven't changed mine and the codes have gone away.

 

[Popell]

Any idea of the parts?, I’ve read your account and certainly see the cover but are there other bits to buy? You mentioned the hoses too.
All the vids I’ve watched just show the rather worn centre seal in the cover.

 

[Conor]

Sorry I didn't answer your previous question about what the PCV does. It stands for Positive Crankcase Ventilation.

Now, I am open to correction from people who know what they are talking about but.. Typically, air comes in the intake, mixes with fuels and the gases resulting from combustion go out the exhaust. Simple, right? Well.. some gases escape through the minuscule gap between the piston and cylinder wall. This is known as "blow-by" The PCV system aims to catch that and recirculate it back into the combustion chamber to be burn, as opposed to letting it off in the atmosphere.

https://en.wikipedia.org/wiki/Crankcase_ventilation_system

I will look up the parts soon and get back to you. Please remind me if I don't come back this weekend.

 

[Larkone]

The PCV valve has a rubber diaphragm which breaks down with heat cycles and age - at 95K I would definitely change it.

Re: Marcedes parts guy thought poss clogged fuel filter due to using some supermarket fuel.
He sells parts and is not a mechanic, supermarket fuel comes from the same refineries as any other forecourt

 

[Popell]

The PCV valve has a rubber diaphragm which breaks down with heat cycles and age - at 95K I would definitely change it.

Re: Marcedes parts guy thought poss clogged fuel filter due to using some supermarket fuel.
He sells parts and is not a mechanic, supermarket fuel comes from the same refineries as any other forecourt

Thanks Larkone, I have often said the same (and having worked in the up stream side of oil and gas, I understand the argument) but started with the easiest possible solutions to my issues.
Conors experience may well be the solution - I hope so, even if the level of difficulty in installing is greater than swapping a MAF.

 

[alexanderfoti]

If its negative across both banks, its indicating that its removing fuel (for whatever reason).

In Conors case, this was coming from the additional oil being pumped into the inlet and being burnt.

This could be the same for you, but other sources of fuel including dribbling fuel injectors or a stuck open egr are both possible. Is it even across both banks?

 

[Popell]

Hey Alex, good morning, thank you for the reply.
The readings do seem to wander a bit , yesterday morning they were heavily negative (double figures) but then tended towards zero/-2ish after warming up a little. LT bank1 is now 0.0% (had been -1.5% over the last couple of days, car not used much) and LTBank2 is +2.3%, had been @0%)
Bank 1 is always less than 2
I had to visit my daughter, 50+miles away) and went on motorway primarily and managed 30.6 overall which is not far off my norm for the trip, returned on A roads and got 28.6, so poss only 2 down on norm, neither trip threw a CEL but I did get a couple pending (P0171/174)
Before I used the Wynn injector cleaner and swapped the plugs, the FTs were both positive +6/+11%ish so something seems to have changed.

Reading late last night, I read something that pointed towards MAF again! I still think it worth doing PCV first but will probably do MAF shortly after. My scan tool has never read a meaningful value on any car I have tried it on for the MAF (Sits at 10.115lb/min)

Tried a bid on a new code reader CRP229 last night but lost it at 4 seconds to go! Might have to stump up for a new one but would be disappointed if it did little more than my old one (Memoscan U581)

Anyway, thank you all for your continuing help and support - Happy new year to you all!

 

[Conor]

I can't advise on MAF issues I am afraid. Although I should probably learn about it and test mine. I am getting woeful MPG (26 Max MPG on motorway) and about 12ish in urban driving. I need to look into it I suppose. Although with 200k Miles on the clock, I imagine a loss on efficiency :/

Anyway, for the PCV system job the parts are as follows:

The following link is just for reference. Scroll down to the bottom and it will guide you to the individual parts/numbers. I would advise getting all OEM for this.

I think I paid £150 for the following.

https://www.ecstuning.com/b-genuine...rator-and-emissions-service-kit/2720181382kt/

 

[Popell]

Hey Conor, thanks for the reply and information.

I couldn’t live with the mileage you’re getting, have you tried compression tests? It makes mine look reasonable!

 

[Conor]

Hey Conor, thanks for the reply and information.

I couldn’t live with the mileage you’re getting, have you tried compression tests? It makes mine look reasonable!

Yea, it's not great, but I don't do massive mileage really so it's not a biiiig problem. I would like to see closer to 30 on motorway trips though.

I haven't tried compression test but the car does burn a lot of oil so I am of the belief that the the piston rings are shot.

 

[Popell]

Yea, it's not great, but I don't do massive mileage really so it's not a biiiig problem. I would like to see closer to 30 on motorway trips though.

I haven't tried compression test but the car does burn a lot of oil so I am of the belief that the the piston rings are shot.

Has the work you did replacing the PCV valve not improved the situation?
BTW the emissions kit you linked to from ecs seems to be for the std 3.5 engine. I was looking at the individual parts and the cover I found for the pcv (ie the part that is a bitch to get to) has part no 2720100531(listed for the 272.983 engine) , not the 2720100631 listed in the kit, the outlet connection seems to come off at different angles, was this the part you used?

 

[Conor]

Has the work you did replacing the PCV valve not improved the situation?
BTW the emissions kit you linked to from ecs seems to be for the std 3.5 engine. I was looking at the individual parts and the cover I found for the pcv (ie the part that is a bitch to get to) has part no 2720100531(listed for the 272.983 engine) , not the 2720100631 listed in the kit, the outlet connection seems to come off at different angles, was this the part you used?

I haven't noticed any marked decrease in fuel consumption - but to be honest, I didn't really ever concern myself with that as I was only doing about 4k miles per year.

I'm very sorry, I must admit that I had only a fleeting look online and was too lazy to fire up my ECP. I have now checked EPC (Electronic Parts Catalogue) and please find complete parts list below, along with diagram from the 983 engine.




Regarding the job - there is a WIS (Workshop manual) showing what needs to be done, but it omits a lot of the great detail. My account on the other thread will really help you.

It's unfortunate that the PCV valve is such a big job on this engine/chassis combo, because it is very much an item that does need to be replaced.

You might do well to look at the MAF sensor first, as that is certainly an easier job. I've been curious about doing that myself, I must figure out how to test it with my STAR.

 

[mioba]

Who read your codes and diagnosed for what you have done yourself.

Having a generic code reader is one thing. If anything they are a can of worms to the undecerning. Having a proper code reader and the ability to interrogate it to correctly pinpoint the problem is an art, skill in itself.

Its easy initially to go down the route of constantly throwing parts and labour at a car till one fixes the issue. But this costs down time, patience and money.

I had a lean on bank 1 error on my R class this year. read from a generic code reader. Googling the codes came up with many possible faults and wallet emptying thoughts.

Took the car to a very good indy. Split high pressure hose. Job done once, paid once and happy.

Dont get me wrong. I am very handy and do most of not all things myself that are purely mechanical, but where code reading and interrogation is involved. Its just not worth it for me.

 

[Conor]

Who read your codes and diagnosed for what you have done yourself.

Having a generic code reader is one thing. If anything they are a can of worms to the undecerning. Having a proper code reader and the ability to interrogate it to correctly pinpoint the problem is an art, skill in itself.

Its easy initially to go down the route of constantly throwing parts and labour at a car till one fixes the issue. But this costs down time, patience and money.

I had a lean on bank 1 error on my R class this year. read from a generic code reader. Googling the codes came up with many possible faults and wallet emptying thoughts.

Took the car to a very good indy. Split high pressure hose. Job done once, paid once and happy.

Dont get me wrong. I am very handy and do most of not all things myself that are purely mechanical, but where code reading and interrogation is involved. Its just not worth it for me.

Yea, this.