Turbo/MAF? Power loss e270!?

[len_merclover]

The saga continues...I know I have posted earlier threads elsewhere but this is the overall picture of my situation. I was driving to work yesterday morning, just left my road when to accelerate but kind of lost any power. (I could put my foot down to the floor and still the speed would increase little). After this I restarted the car, and everything was great.

Now today guess what? The same thing happened in the same place – after leaving for work! Now I was told yesterday that it was the turbo diesel need replacing and sensors? (The engineer who came out thought it was weird that all the fault history of the car was still on the print out). Anyway, I stopped the car and restarted and everything great again. After restarting on the initial acceleration it didn’t want to change gear then it did at high revs and seemed like a ‘kick’ when it changed? See I’m no mechanic but surely if it was the turbo diesel this would happen intermittently all over the show, not the same area etc? I restart the car again, to go to get some lunch say and everything is great all day until the morning start....now can anyone help me please? I don’t want to be forking out over £1,000 for parts and labour to find it will happen again. The strange thing is no fault or malfunction lights come on. I was told that if the turbo was ‘on its way out’ there would be smoke coming from the exhaust?
I have read many many threads in relation the sudden power loss etc and see people all saying about the MAP/MAS or something to do with the air meter? But never the turbo.......can anyone please give me some tips or advice etc?

Many many thanks.
Len.

 

[colechelle]

If on short test it comes up with air mass sensor, then easy fix, not cheap, if its showing charge pressure sensor (signal to high,low) then the vains on the waste gate are sticking, not unheard of, then yes turbo venting hence no power, would need some more info from star report if you have it at all??

 

[len_merclover]

... After having the Mercedes Mobilo man come on (didn’t think he was all that) he suggested the turbo unit. One of the reasons I think he was getting confused was all the faults that had ever happened had been left on plus it was nearly 5 and he wanted to get home. (ha, he said that one entry stored was because all my 4 sensors have been knocked out!!! ... ) I found out this was just where the wheels have 'spun' and its been recorded! lol and the turbo unit which I would have had to replace would have cost in the region of £1500 - luckily for me I got a techi to check and he put it down the mass air meter/ flow or something! mmmmmm !

Len

 

[len_merclover]

fault code 0105-001: Check component B5/1 (charge pressure sensor). This signal voltage is too high. & 1636-004: check component M4/7 (Engine and AC electric suction fan with integrated control) Signal wire OPEN CIRCUIT.

 

[jberks]

it could be lots of things and the comouter diagnostic/error codes are notoriously unreliable. So its always going to be at least partially guess work. I'm sure if interrogated, mine would spit out all sorts of fault codes, but she's running fine.

The MAS/MAF/Airflow meter are all the same thing. Basically its a gizmo that sits in the air intake just after the filter. It tells the computer the volume and temperature of the incoming air, which it then uses to match the fuel volumes. This is then compared to the unburnt fuel information provided by the O2 sensor in the exhaust and between them, the ECU tries to get the most efficient mixture.

Over the years, muck still gets to the sensor and with air passing through, plus it's rather stressful self clean mechanism, the sensor simply wears out. Life expectancy varies but it's not uncommon for them to start playing up after 3 years or so. The difficulty with diagnosis is that they work by putting out a voltage within a fixed range. Provided the voltage remains within that range, the computer may choose to believe it, even if it's actually wrong for the air volumes/temp at that moment. If so, the computer may decide to mis trust something else that is contradicting it further down the track instead and hence the fault code could be wrong. At the end of the day, the computer has got 2 contradictory readings and has to make a decision.

A MAS is around £60, 5 mins to replace and if its more than a couple of years old, will be past it's best anyway - hence it's the best, and by far cheapest, place to start, aside from the fact that it's the most common failure anyway. Once ruled out, if the fault persists, proper diagnosis can begin with a lot more confidence.

Do not be tempted with the ebay versions as they can be worse than your old one. You can often buy the guts of the unit from a Bosch agent for a fraction of the dealer cost, keep your housing and swap the guts over, but it does depend on what the dealer wants for a new one as they can vary between £60 and £250 depending on model. Clearly with the £60 one its not worth the effort.

Good luck and let us know how you go on.

 

[len_merclover]

many thanks - I will try and find a retailer today or weekend ..... do you know or anyone know of retailers for these in in maidstone area of kent?
thanks

 

[len_merclover]

I have called numerous auto part shops - the bosch center doesnt stock mine ! but 2 places so far come back with prices much higher than £60. One was £145 + vat (£173) and the other was £155 + vat (£182).

Not sure what to do now as I have seen re-conditioned turbo units for £280 + vat (£310) from the recomended site from here (garrets). See, if I change the MAS for £173 and its not that then the turbo unit will cost £280 so in total £450 ish..........

would my turbo unit cause the problem I'm having though?

 

[kth286]

Len

See your tyre thread first and action proposal as it may save you money and cure fault.

 

[ChrisBillson]

Mine had the same symptoms and it turned out to be the primary cat.

 

[len_merclover]

just an update - replaced air mass sensor and works fine now ...so far soo good thanks to evryone for their help

 

[jberks]

Great news - thanks for letting us know.