[Chevota]

This '98 ML320 will stall when put in gear after a cold night unless it's fully warmed-up. I've been unable to solve this problem for months. The dealer has no clue what's wrong (as I expected).
It feels to me more like the tranny is dragging the motor down rather than the engine is having trouble as I originally assumed. It's hard to get a good feel with this throttle-by-wire BS, but I'm really suspecting the tranny/torque converter. Does anyone have any thoughts??
80K miles, original tranny, original everything. Trans fluid change, no effect.
MAF sensor change, no effect.
Throttle body clean, no effect.
Banging my head against the wall, no effect.

 

[gary1378]

same problem i have

you know what i do and it helps a little
i warm the car fo 5 min in Neutrel and then proceed it works better the gear tends to switch more smoothly
i know i dont make sense but it helps my case

 

[Chevota]

Actually that is helpful. For one it means I'm not the only one in the world with this problem. So you do notice a difference in transmission engagement when it's cold vs hot?

The car is my mothers and she lives a few hundred miles from me so I don't get to troubleshoot it very much. She lives at a higher altitude than I do so it's much colder. She claims that in the morning it will stall anytime she puts in gear unless it's fully 100% warmed up. This is obviously very annoying. It can cool off while she's at work and start/drive fine, but I guess overnight is too cold??

 

[ML430ish]

hmm, chevota in russian means something[^]

 

[Darkmann]

Chevota - 1/25/2005 12:59 PM

This '98 ML320 will stall when put in gear after a cold night unless it's fully warmed-up. I've been unable to solve this problem for months. The dealer has no clue what's wrong (as I expected).
It feels to me more like the tranny is dragging the motor down rather than the engine is having trouble as I originally assumed. It's hard to get a good feel with this throttle-by-wire BS, but I'm really suspecting the tranny/torque converter. Does anyone have any thoughts??
80K miles, original tranny, original everything. Trans fluid change, no effect.
MAF sensor change, no effect.
Throttle body clean, no effect.
Banging my head against the wall, no effect.

Stop banging your head against the wall. I agree with you that it's most likely the torque converter. Isn't there a way to test tranny idle torque? What's unusual is that at cold start the engine RPM is high and you'd expect the engine output much higher that the tranny idle torque. Check a few things:

1) Cold start and idle RPM (I don't know what the specs are but I believe idle is 750 and cold start may be up to 1200) - I have the feeling this is not a problem with the truck.
2) Is your fuel consumption higher - may indicate "tight" tranny.
3) This could also be a non-tranny related stall due to a malfunctioning temperature sensor. I recall in another brand, a bad cylinder head temp sensor would buck the car so bad until it attained operating temps. Both of you may really want to look into this.

One other thing that may happen is carbon build up in the intake/exhaust valves - usually due to poor fuel quality. It would cause bucking, hesitation and maybe stall until warmed up. You can easily eliminate this option by using a good fuel additive to the system (I have used BG44K in other cars with success. There's a BMW recommended cleaner also you can get from a dealer - it doesn't do any better than BG though, your choice). I know MB doesn't recommend doing this, but unless there's a MB recommended cleaner, BG works well for a lot of gasoline injected vehicles. If it clears it up, then that may be the problem. It's a temporary solution though!!!

Tough one but I hope this helps some.

 

[dakat]

I may be way out in left field on this,but.........I once had a Buick that would do that even when warm. I had to figure it out for them finally. After you get in the top gear there is a solenoid that locks up the torque converter. This unit would fail keeping the torque converter locked when you shut off the engine. When you started it up next time and put it in gear it would be in 2 gears at once, and kill the engine. The cold weather may be causing this unit to stick or fail. You may ask Gilly about this over on the shop forum, as Mercedes may be different, but I'm sure they have locking torque converters.....good luck. Oh, by the way, talk to your shop foreman, not your SA, they're only scribes in my opinion! [8D]

 

[Chevota]

ML430ish:
What does it mean over there?

Here it means Chevy motor in a Toyota. Usually a V8 in a in truck or Land Cruiser. I have a 4X4 truck/V8.

 

[jdanish]

Dakat is correct, old gm trans would stay locked up, not sure the benz would because you would lug down on startoff with a 5 speed.
I would check the idle circuit, engine should increase to cover the load, plus high charge rate on the alternator and so on.
Find someone to install a scanner on it during startup and watch the idle % values, the value should increase, if not it could be idle control or ECM monitoring?
jd

 

[ML430ish]

Chevota - 1/27/2005 4:52 AM

ML430ish:
What does it mean over there?

Here it means Chevy motor in a Toyota. Usually a V8 in a in truck or Land Cruiser. I have a 4X4 truck/V8.

"something"[}]