C270 wont go over 2000rpm

[martink]

Hi,

Any idea's on this one.

I own a C270CDI, 2001 model. After a few minutes of driving my car it wont go above 2000rpm. I can get to what ever speed I like, but takes a lot longer cause it wont exceed 2000rpm. Its on the S mode and not W. Any comments or idea's? I would be greatfull. I have noticed that I cant hear the turbo. Its like it in a safe mode or something.

Also, anyone know where I can get cheap parts from online? ie brake pad sensors!

Many Thanks

 

[television]

Clean or replace the MAF, it should solve it, go to the engine section, it heads the list.

Malcolm

 

[martink]

thanks for your comments television.

I have taken it to a local garage, who have run the diagnostic computer on it. Error message :

P0100 B2/5 (Hot film MAF sensor) The signal voltage is to high.

I need the MAF replaced.

Any idea's where i can buy one online?

Thanks

Martin

 

[television]

You can clean the original,(it cost nothing), buy from Ebay,(the cheapest), or buy an insert from any Bosch agent ( cheaper than MB) or MB


Malcolm

 

[hawk20]

You can clean the original,(it cost nothing), buy from Ebay,(the cheapest), or buy an insert from any Bosch agent ( cheaper than MB) or MB


Malcolm

How did you know, straight away it was the MAF, and can you explain in simple terms what it does and why it goes wrong. please?:smile:

 

[television]

Yes, I will do that over the week end, I have to work tomorrow.
I will keep it simple.

Malcolm:roll:

 

[martink]

Thanks for the replys!

I have replaced the MAF with a new one, costing £60. Its an original MB Part. It now goes over the 2000rpm, but now the turbo isnt kicking in! My friend suggested resetting it via computer using some diagnostic software. I'll be doing this thursday/friday evening.

Not unless I should be doing something else?

Martin

 

[psmart]

Its one of the complex problems, your MAF may not have been faulty, or it was taken down by something else.

There is no procedure to reset the ECU for the turbo to spin up, the turbo not spinning up means the ECU has identified another problem, or something has gone wrong with your vacuum. Have a look at this thread, http://forums.mercedesclub.org.uk/showthread.php?t=19930 something similar to yours. Check the air cleaner (simple things first), is the guage all red or all white?

Can you give us more info to go on, I may be able to help further, having had experience in this area and also having a diagnostic system to hand.

 

[hawk20]

Its one of the complex problems, your MAF may not have been faulty, or it was taken down by something else.

There is no procedure to reset the ECU for the turbo to spin up, the turbo not spinning up means the ECU has identified another problem, or something has gone wrong with your vacuum. Have a look at this thread, http://forums.mercedesclub.org.uk/showthread.php?t=19930 something similar to yours. Check the air cleaner (simple things first), is the guage all red or all white?

Can you give us more info to go on, I may be able to help further, having had experience in this area and also having a diagnostic system to hand.

Psmart I read your other thread. This is every motorist's nightmare. A problem with loads of potential causes. I've always been a fan of going to Merc dealers. I know views differ. I've had excellent service. But with something like this, wouldn't a Merc dealer have the equipment to find what was at fault, or access to technical people at mercedes to narrow it down. Or would it just be change this, then that then the other until we find a cure???

 

[psmart]

Psmart I read your other thread. This is every motorist's nightmare. A problem with loads of potential causes. I've always been a fan of going to Merc dealers. I know views differ. I've had excellent service. But with something like this, wouldn't a Merc dealer have the equipment to find what was at fault, or access to technical people at mercedes to narrow it down. Or would it just be change this, then that then the other until we find a cure???

This is why I keep on suggesting a forum area for feedback on dealers and Indies. There will be good ones out there, but I personally wont take a risk, most will just component swap at your expense, or even worse, rip you off. Lets not forget that a lot of Indies are the experienced Merc Dealership mechanics that setup shop for themselves, and most have the diagnostic equipment themselves. Next time your at a dealer, play spot the 'zit' (kids) and ask yourself if these guys are going to have experience? Dealerships may have access to Merc inside knowledge, but Indies do as well (our C had an ABS/ESP fault and through contacts, found it was a wiring harness). This forum is a repository of knowledge, just like the US and the MBClub.

I spent a few Gs on my own diagnostic equipment, dont want to be caught with my pants down next time! Diagnostic equipment is only 50% there, intelligence, fault finding mentality, experience and time are the other 50%.

 

[television]

Psmart I read your other thread. This is every motorist's nightmare. A problem with loads of potential causes. I've always been a fan of going to Merc dealers. I know views differ. I've had excellent service. But with something like this, wouldn't a Merc dealer have the equipment to find what was at fault, or access to technical people at mercedes to narrow it down. Or would it just be change this, then that then the other until we find a cure???

As psmart's thread, it is a jungle out there. MB are in the main OK for straight forward faults. Straight forward that is until something different comes along, We had one chap who had a seat problem, with seat only moving in one direction, the estimate from MB read, "to replacing seat switch bank, 4 new motor's and a new wiring harness, £487 + labour =£1000". he could not miss the fault.

Going back to the MAF, this device that measures air flow and air temperture is used set up the fuel / air ratio, very much like the simple choke of years gone by setting the mixture and timing of the engine and more.

One effect a faulty or dirty MAF has, is to make other components deviate from their stored memory positions, so when a fault code read out is done, everything other than the MAF comes up as faulty, in the worst cases MB dealers have been known to change many parts and still not found the fault.

Most faults are electrical, this is where modern paperless work sheets fall down. As everyone knows I have access to the WIS program the wiring diagrams are almost imposible to make head or tails of. I have been working by diagrams my whole life from 1947. first we used to have a block diagram that showed the signal paths,power supply paths and so on, computer generated circuits show nothing, and show to the once loved block diagram, they are impossible to make sense of. The only way for me to get through these jobs is to call on my own knowledge as to how these things work. One serious problem is that no one is going into the electronic trade as such, I think that I am right to say that there are no more than two coarses per year. Car engineers do not go on electronic coarses and they do notknow how individual components work. If one does not know the basic fundermentals, what hope is there of finding an obscure fault. If you were to ask a car eng; what a resistor or condenser does, he might give you one answer, where as of coarse there are too many to list here. I could go on all day, but it does not help, even thought of mixing delicate electronic components with dirty cars is bad enough, a few dirty hands, unpluging a component when live, you may fix one problem, but soon create another.

Malcolm

 

[hawk20]

As psmart's thread, it is a jungle out there.
One effect a faulty or dirty MAF has, is to make other components deviate from their stored memory positions, so when a fault code read out is done, everything other than the MAF comes up as faulty, in the worst cases MB dealers have been known to change many parts and still not found the fault.

Car engineers do not go on electronic coarses and they do notknow how individual components work. If one does not know the basic fundermentals, what hope is there of finding an obscure fault. If you were to ask a car eng; what a resistor or condenser does, he might give you one answer, where as of coarse there are too many to list here. I could go on all day, but it does not help, even thought of mixing delicate electronic components with dirty cars is bad enough, a few dirty hands, unpluging a component when live, you may fix one problem, but soon create another.

Malcolm

Thanks Malcolm. The more I hear and read the more I wonder where we are going and why. When I had a Riley 1.5, we could strip the engine, tune the SU carbs, play tunes on it. Now I look under the bonnet and think 'Jeez, get me to a dealer with factory trained mechanics'. But what have we really gained? My 1960'3 Riley 1.5 (tuned a bit) would do a ton. Plenty in modern traffic with all the speed limits. What have we really gained from all the electronics compared with all the bills and complexities as things start to go wrong?

 

[psmart]

One serious problem is that no one is going into the electronic trade as such, I think that I am right to say that there are no more than two coarses per year. Car engineers do not go on electronic coarses and they do notknow how individual components work. If one does not know the basic fundermentals, what hope is there of finding an obscure fault. If you were to ask a car eng; what a resistor or condenser does, he might give you one answer, where as of coarse there are too many to list here. I could go on all day, but it does not help, even thought of mixing delicate electronic components with dirty cars is bad enough, a few dirty hands, unpluging a component when live, you may fix one problem, but soon create another.

You need to be very intelligent or dedicated to understand and work on electronics, let alone fault find (a level above design), so why waste 3-6 years of your life, taking the degrees, proving you can work in this field, then get paid 20Grand per year? I majored in Microelectronics, I love the subject and still do, but it doesnt pay the bills! Herein lies a catch22. Do you think a mechanic is going to spend so much time and cost to understand electronics, just to get 20Grand a year or less? If they've got the expertise, they'll move out into other professions, hence we are left with module and part swappers. Their are bound to be damned good mechanics out there who have got a whole repetoir of skills, including electronics, but I wouldnt expect to find one at a bog standard dealership!

But its not just electronics, you need to be familiar with fluid dynamics and a whole host of other technologies in order to understand a car. I wonder how long it will be before cars are just disposed of when a fault occurs, a bit like audio/video/PC's today?

 

[television]

Thanks Malcolm. The more I hear and read the more I wonder where we are going and why. When I had a Riley 1.5, we could strip the engine, tune the SU carbs, play tunes on it. Now I look under the bonnet and think 'Jeez, get me to a dealer with factory trained mechanics'. But what have we really gained? My 1960'3 Riley 1.5 (tuned a bit) would do a ton. Plenty in modern traffic with all the speed limits. What have we really gained from all the electronics compared with all the bills and complexities as things start to go wrong?

All said and done we must keep this in the correct context, 99% of the cars go through life with no real problems, there is, and always will be the rouge one, the same goes for the guy trying to fix it.
What have we gained, I used to like driving my 1928 RR the engineering was really some thing, these days, an MB please,

Whilst giving a lecture to the RR car club,I told the people there to be careful with twin carbs, and adjusting them, as if you were not careful you could get the front half of the engine going faster than the back, and that would break the crankshaft in half, not one person qustioned this, amazing.

You should go to the Bosch website and see whats waiting around the corner.


Malcolm

 

[martink]

Tried resetting all the error messages, did an extensive computer check using the x-431 diagnostic computer at the local garage. Everything seems fines except its still not performing like it should.

Turbo still not kicking in! Also when in park it shouldnt be able to go above all the way into the red when flooring it.

So on friday I'll be taking it friend of a friend at a mercedes dealership to see what they can suggest.

I'll update more then.

Cheers

 

[psmart]

What were the error messages?

 

[television]

Tried resetting all the error messages, did an extensive computer check using the x-431 diagnostic computer at the local garage. Everything seems fines except its still not performing like it should.

Turbo still not kicking in! Also when in park it shouldnt be able to go above all the way into the red when flooring it.

So on friday I'll be taking it friend of a friend at a mercedes dealership to see what they can suggest.

I'll update more then.

Cheers

The limit in park for all MB's is 4k,and this is done by cutting off the fuel above theis figure, I too would like to know what the fault codes were.

Malcolm

 

[martink]

Diagnostic software hasnt picked anything else up. Its still revving up in the red when stationary, normally would go up to 2,500rpm. Turbo still not kicking in. Spoke to some engineers at mercedes, they suggested checking the pipes that go into the turbo, to make sure theres no splits. It will be going up on a ramp later, to look for any splits etc. I'll post more on here after.

Its seriously annoying me now!

 

[martink]

sorry, only just read the comment to my prev posting. Fault code :

P0100 B2/5 (Hot film MAF sensor) The signal voltage is to high.

Symtoms - I can rev the into the red when parked.
- Turbo not kicking in (hence the loss of power)

I hope the turbo doesnt need replacing! How long are they normally good for?

Martin

 

[psmart]

You'd know when your Turbo goes, either a ghastly grating sound, a sudden bang with a wallop of grey white smoke out the exhaust, a destroyed engine etc!

When they are going, they get very noisy, with a mechanical grating sound and lack of power. If you dont get them seen to, you could end up losing your engine! Some are known to just go, taking the engine out without any forewarning.

On Petrol, they'd last circa 60Kmiles, on Diesel, there supposed to be 100K plus minimum as Diesel doesnt get as high in temperature, minimising wear.

I replaced mine at 59Kmiles, because of a production fault causing the Turbo and manifold to be twisted under stress, but this is not normal.

If no faults are being reported, other than MAF, Id suspect the vacuum pipe to the Turbo or a leak on the Turbo compressor outlet piping (intercooler etc). If you look at the photos in this thread, http://forums.mercedesclub.org.uk/showthread.php?t=17603 , same engine as yours, you can identify the turbo. Turn your engine off, and look at the arm on the turbo, which rises from the disc like valve at the bottom to a lever on the side of the turbo turbine. Note its position, then start your engine. Has the arm/lever moved? If not, then you have a vacuum failure or the BPCVT control valve on the sidewall has gone faulty. If its moved, then your turbo is spinning up, so either the ECU is disabling it the moment you drive, or you have a leak in the piping going from the Turbo to the intercooler (radiator at front of car) or into the inlet manifold. Also possible for your EGR valve to be stuck open, but I havent tested this scenario, so not 100% sure of its consequences.

Another possibility is your exhaust being blocked up because of a Cat breakdown. Can your local garage do an exhaust pressure test?