Engine Fault causing poor gearchange

[davidjpowell]

My car (a w203 C320 cdi) has been into a gearbox specialist due to a bad change.

He has said gearbox is fine, and the poor change is due to an engine fault that is reporting a false pressure/reading to the computer, hence the gearbox thinks the engine is at 50% power, when in reality it's at 10%. He also says this is causing over-fuelling.

Trader is booking it into his specialist (bet he needs reminding), but in the meantime does anyone have any ideas?


This does explain why the change is perfect when floored - 100% is 100% after all.

 

[BlackC55]

Does it have a lack of power?

7g's change gears badly as a rule. Especially the early ones. Mine does and that's just the way it is.

There are ways to improve it with software updates and re-adapting the torque converter with a Star.

What does it do? Is it an up change issue?

 

[davidjpowell]

Power is fine - it's not Port inlet shutoff if that's where you are headed!

It's 1-2 and 2-3 up and down. Changes harshly and sometimes on the up-change its like power vanishes for a split second.

The gearbox guy certainly talked the business, has updated the software and re-adapted at proper temp's etc. He's looked at the actual pressures.

I've had 320 cdi in the past so am accustomed to the not great 1st to 2nd change, but this is far worse.

 

[BlackC55]

Does he have access to the MB software updates? They are done online via Germany MB. I would be very surprised if he does as we don't!

All the software updates we do go to main dealer. The updates change often.

Is the level ok? Its tricky to check. Are there any codes in the engine?

The box could be worn. It make take a strip down to find the issue.

 

[davidjpowell]

Does he have access to the MB software updates? They are done online via Germany MB. I would be very surprised if he does as we don't!

All the software updates we do go to main dealer. The updates change often.

Is the level ok? Its tricky to check. Are there any codes in the engine?

The box could be worn. It make take a strip down to find the issue.

I think he does. He was waiting till yesterday evening to go online as the network was busy,

SPX know's the guy and has said he's good also.

He's looked at pressure's in the gearbox and believes it's healthy (healthier than he normally see's). I don't know enough, other than to say he is very plausible. I think he believes that if there is an issue it would have been the valve body. I assume he's checked the Oil.

He mentioned over-fuelling and this did make some sense as it is quite smokey. He said there was an engine related code, but was clear that he's not going to get involved in anything other than gearboxes.

I'm tempted to take it to an indy to get codes read myself, before it goes to traders guy, but can't see me having time.

Thanks for our help Olly.

 

[WG M-B]

If the torque output from the engine is not right the transmission will act as you described

 

[davidjpowell]

Car is in at traders specialist today. He's decided it needs an ECU update, but does not have the gear. Its off to MB on Saturday.

I'm not every so happy with this, as I simply don't believe it's the fix.

I have noticed that it stumbles when starting cold. Gearbox specialist said it was very smoky. I'm wondering about an air leak, and whether that could cause these symptoms?

I could do with getting the car back sometime soon...

 

[davidjpowell]

Well my car is going around like a roundabout. Where it stops no-one knows.

MB have updated software, still doing it. They've said it's the Torque Convertor. Now heading back to original gearbox specialist.

I can't really complaint about the trader. But it's getting a little annoying haven got rid of our third car right when it would be useful. Hertz looks like I'm coning your way. Again.

 

[davidjpowell]

Still broke. Still no car

 

[GilerK]

sorry to hear .my W220 gear slip and I am servicing the transmission ( filter n check the conductor plate and solenoid). Hope it will be fix by monday.

 

[DSB SL AMG]

Have you not got a good local MB indy you can get a 2nd opinion off?

 

[davidjpowell]

Car so far has been to:

1. Gearbox specialist - he diagnosed an engine fault
2. Mercedes specialist (not one I know) - diagnosed update ecu
3. Dealer. Upgraded ECU - diagnosed valve body (some talk of torque converter also - but no one knows where that came from!
4. Bosch specialist - recommended by gearbox bloke. Thinks faulty gearbox
5. Gearbox specialist - currently re-considering his diagnosis.......

 

[trapperjohn]

Hope you get it fettled soon David.

 

[davidjpowell]

Me too John. I'm missing the car.

In the meantime I made the mistake of selling the Polo for S&R as that was using too much oil. I've now been forced to buy a Clio for my wife to use, while I use the Range Rover, as I was paying Hertz too much money!

 

[wemorgan]

Oh heck, fingers crossed the bill isn't too dear.

 

[trapperjohn]

Aint that just the law. Murphy's that is. Toying with the idea of moving on my 124 saloon, but I know as soon as I shift it, it would have come in handy for something or another family member.

 

[davidjpowell]

Oh heck, fingers crossed the bill isn't too dear.

Bill belongs to the trader seller who is being fairly good,until push comes to shove. Inconvenience is all mine

 

[davidjpowell]

I think the car is cured. It's had a new Valve body and I am very happy to get it back. :bannana::bannana:

 

[davidjpowell]

Thought I'd come back to this. The car was not cured by the valve body. I've been investigating rather than role the dice which see's the trader cart if from garage to garage with the help of the gearbox specialist.

He had a look at the error codes last night. I've fitted a new MAF today, and it's cured.

 

[Aussie Baz]

Hi guys,Ive been down this track its driving me nuts. Have had the transmission recondition & tc, replaced MAP, been on the Star a hundred times, no codes & the best it got is when they readapted the transmission at my request. After 3 months problem had returned as if something looses its memory ,Replaced the TCM & had it mated to ECU & had it readapted again & all gear change is like new again for a few months then the change is all over the place again. What I do now to get the change back to normal is disconnect the TCM under the mat for a 1/2 hour or so reconnect & problem is solved for a few months. Anyone got any ideas. regards baz