E300TD low torque?????

[230K]

Hi all

My 98 E300Td seems low on grunt it needs reved above 3K to make anything happen, noticable on Motorway on a hill it just seems not as torquey as it should be having to resort to kickdown to get any serious shove. Is this normal? All else is fine mpg, starting etc
Fuel and air filters changed at last service 6K ago.

Any ideas

230K

 

[Brian WH]

Hi all

My 98 E300Td seems low on grunt it needs reved above 3K to make anything happen, noticable on Motorway on a hill it just seems not as torquey as it should be having to resort to kickdown to get any serious shove. Is this normal? All else is fine mpg, starting etc
Fuel and air filters changed at last service 6K ago.

Any ideas

230K

Has this just happened? Did it used to be a lot better?

If so I would plump for the turbo not performing?

 

[jimmy]

Yes, check the charge pipes to make sure they have not blown apart at any joints. Could be a sticking wastegate too.

You could try an ECU reset, leave the battery disconnected for 20 minutes or so, dont forget to make sure you have the radio keycode and you know how to reset the windows first!

 

[230K]

Has this just happened? Did it used to be a lot better?

If so I would plump for the turbo not performing?

There was no drastic change, only had car 6 months, drove a friends exact same spec year & v similar milage and his seemed more torquey and he drove mine and thought mine was slower but when reved seemed faster. VW/Audi's seem to have big changes in poke when their MAS are changed, this car is currently on her 3rd MAF since new do they wear out or whatever and how much would a replacement be and does the computer need reset if it is changed?

230K

 

[230K]

Yes, check the charge pipes to make sure they have not blown apart at any joints. Could be a sticking wastegate too.

You could try an ECU reset, leave the battery disconnected for 20 minutes or so, dont forget to make sure you have the radio keycode and you know how to reset the windows first!

No charge pipes seem to be leaking, disconnected battery for over an hour but no noticable difference in poke. How do you reset windows?

230K

 

[jimmy]

Can you hear the turbo whistling? Is the turbo boost noticable? Could be the wastegate stuck open.

You reset the windows by lowering slightly, then holding each switch in the first up position until you hear a click from within each door, takes a couple of seconds for each window.

 

[Benzowner]

Have you got your gear selector switch in W or S, stupid thing I did , acceleration in W from standstill not very good , seems to be a lag. Its because the car is pulling away in second. Flicked the swiths to S and all was restored :bannana: . Hope its that easy.

 

[Alex Argent]

Could be the MAF sensor on its way out (especially if you have recently had an air filter change - movement of the air ducting can disturb the delicate sensor just downstream of the filter housing). However, most problems encountered with a dodgy one (uneven tickover, holding gear on an auto box, lack of acceleration/power, etc) seem to temporarily 'go away' each time the ignition is switched off and then restarted, until the fault code is then next registered by the ECU. Disconnecting the battery apparently does not clear any fault codes, it simply resets the ECU.
Had mine replaced last week by the stealership (Robinson's - Bury St Edmunds - £300 ) who I gave 10/10 for their service and promptness in locating the problem. They actually fitted a replacement just to ensure it was the MAF sensor because a couple of older fault codes were registered on the ECU. The difference in power delivery is unbelievable. I really didn't realise what I had been missing for the past 12 months or so!! Maybe you could ask your local friendly stealer to do the same. I think the diesel one is significantly less expensive than the petrol equivalent in any case. About £60-£70 for the part I believe (and about 5 minutes to fit!).
Yes, the dealer is supposed to clear all fault codes from the ECU before it leaves the workshop (unless you ask them differently I assume).
Hope this helps!

 

[mark.t]

low torque

has the car been chipped previously...before you owned it ..could this unit fail giving you a more factory made drive than the chipped one just a thought

 

[230K]

Can you hear the turbo whistling? Is the turbo boost noticable? Could be the wastegate stuck open.

You reset the windows by lowering slightly, then holding each switch in the first up position until you hear a click from within each door, takes a couple of seconds for each window.

Thanks jimmy got the windows working properly at least.
Can hear the turbo whistling and the boost is noticable there just seems to be nothing before 3000rpm, while max torque is supposed to be as low as 1600rpm.

Another reason why i think something is wrong is that a A6 2.5TDI Estate left me for dust the other day on a sprint away from lights on to motorway.

230K

 

[230K]

Geoff & Mark

W/S switch is working i can feel that and i dont think car was chipped previously (guy who owned it prev from new told me everything and nothing has turned out to be un-true yet!!) but you never know.

Thanks

230K

 

[Dieselman]

I would say that the MAF sensor is possibly faulty so isn't fuelling the engine up enough.

Bear in mind that this is a indirect diesel as opposed to the Audi direct injection, so torque will not be so readily available. The auto box also takes some winding up.

Definately check the gearbox switches between S and W as it could be stuck in W without you knowing.

Also check the accelerator cable is tight enough to pull the potentiometer all the way just before the kickdown switch is activated, otherwise you are engaging kickdown but not fuelling the engine fully.

You can test your own MAF with a digital voltmeter and boost with a pressure guage. It's useful to know these figures.

Here are my test results.

http://mbclub.co.uk/forums/showpost.php?p=35102&postcount=35

 

[230K]

Dieselman

I will check the price of a new MAS tomorrow and if it isn't too bad i'll change it, the only thing is the car is starting and running perfectly no smoke at all and good economy, would hate to mess with it and change all.

W/S switch is definitely working properly

Over which wires on the MAS do you check voltage?

230K

 

[Dieselman]

The price is about £170 so don't do it until you're sure.

Meter the MAF from pin 4 of the MAF connector or pin 24 on ECU connector. Pin outs are 12v, Gnd, 5v ref, 0-5v output.

Metering from the ECU is easier once the connector cover is unscrewed.

Measure with respect to Gnd.

The best way to find pin 24 is to disconnect the MAF and ECU connectors and test continuity on the cable.

IIRC pin 24 is in the centre row and third in from the drivers side of the ECU connector.

The car will run perfectly at idle as it doesn't use the MAF due to it being bypassed by the throttle pot idle switch.

Just sit in the car and rev it in 500 rpm stages and note the readings. Best to do this with a passenger or dictaphone if you need the under load figures.

For boost measurement just T into the manifold pressure sensor connection on the N/s inner wing. Don't forget boost could be down if the engine isn't fuelling up enough.

One other thing to check is for air in the fuel. See if you have bubbles flowing into the pump. If you have this may retard the injection, but is normally accompanied by smoke under load.

 

[230K]

Dieselman

tested my MAS (pin 5 was 0-5v output and not pin 4 which was the 5v ref pin) and have plotted as below.i am slightly more and slightly less at different revs but overall it is more or less consistent with your new sensor.what do you think?Had to have an assistant with me to jot down the loaded values.



 

[Dieselman]

Sorry about the pin out being wrong.

I would say your sensor is possibly down fractionally but is Ok. I would be surprised if the difference translated into any power loss as it's very close. Also don't forget I have polished my turbo so may be passing slightly more air at given revs.

Bear in mind my old sensor wasn't causing any driveability issue and was only picked up because the engine was a bit down on output at our rolling road GTG.
It may be worth giving it a clean with some carburettor cleaner or other solvent.

As you have found testing the sensor is easier than people think, so why do garages revert to guesswork.

Keep your money in your pocket.

Check the boost and that the wastgate is closing fully then leave alone. The wastegate link is available from under the car once the o/s engine mount heat shield has been removed.
You could have the timing checked as I doubt you have the tool for this, but I bet it's spot on.

Also don't forget this is a 24V motor and they really thrive on revs. The more I think about it the more I think your performance is normal.

 

[230K]

Dieselman

Thanks for all the info and advice i'll leave all well enough alone and use kickdown more often when in a hurry.
The next time i have car up on the 2 poster i'll remove the heat shield and check the waste gate, and maybe look about rigging up a boost guage to check the turbo etc.

Checking the MAS was definitely a lot easier than i thought, although i could not have done it without the help of a nephew to read the multimeter.
Total time taken to check MAS 45mins, total time to plot graph and post it on site 3hrs!!!!!!!!

Thanks again

230K

 

[230K]

Dieselman

While changing oil over the weekend i had a fiddle around at the wastegate, the plunger moves freely enough but where the rod enters the turbo there seems to be a lot of play in the and a rattly type of noise as if it were not seating very tight when closed. I assume that when the car is not running the waste gate is closed.

Should there be play were the rod enters the turbo and should the wastegate seat tightly closed?

Thanks

230K

 

[Dieselman]

Dieselman

While changing oil over the weekend i had a fiddle around at the wastegate, the plunger moves freely enough but where the rod enters the turbo there seems to be a lot of play in the and a rattly type of noise as if it were not seating very tight when closed. I assume that when the car is not running the waste gate is closed.

Should there be play were the rod enters the turbo and should the wastegate seat tightly closed?

Thanks

230K

The wastgate is open when the engine is off. The vacuum applied through the boost control modulator is what closes the wastegate.
Suck on the vacuum pipe attached to the wastgate and you will see the rod pulled to close the flap valve. As long as the valve closes and the rod is pulled tight, before the vacuum transducer runs out of travel, then the wastegate will be fully closed.

The setup creates a fail-safe in that if any part fails the wastegate is let go. This is what happens in limp home mode.

You can see the wastegate link operate from above when you start the engine.