[vladmury]

I am trying to find an answer to my issue. Short story if I put the car in D and remove the foot from the brake pedal, the car will slightly move unless its downhill.

I had a bmw 320d e90 before and immediately after letting off the brake, the car will move forward at 5 kmh or so. This will happen also on a steep hill.

However on my new car M57 325d it seems like that does not happen. Should I be worried that the torque converter playing up here?
Are your cars doing the same?

Thanks

[sukutash]

That's definitely not normal unless you're on a VERY steep hill. Even on a very steep hill, it won't roll back, it stays stationary.

[Persian Whisperjet]

Maybe check the transmission fluid level?

[vladmury]

It wont roll back but it wont move forward on a steep hill unless I press the gas pedal.
The transmission fluid is changed and there are no leaks, its level is ok.

My idea is because the idle is set at 700 rpm on M57 the engine does not have so much power to push the car without the accelerator pedal pressed.

At 320d the idle is sat at 870 rpm so it has more power.

[charlie fairmont]

Sorry I don't have anything to help but I definitely agree with sukutash that it is not normal. Mine moves forward at idle with my boat hooked to the back.

[lnxguy]

Brakes dragging?

[Wolf 335]

Mine is not a diesel, but I can tell you that as soon as I let go of the brake the car takes off, and my idle is at 600-700rpm.

As Inxbuy said, maybe one of your calipers is getting stuck.

Try jacking up the car and spinning the wheels to see if there is free movement.

[Persian Whisperjet]

Originally Posted by vladmury

It wont roll back but it wont move forward on a steep hill unless I press the gas pedal.

Won't roll forward on a steep hill? This sounds normal to me.

[vladmury]

The calipers are not stuck, the problem is I believe from the torque converter. The car has an hesitation between 1800-2000 rpm when applying light throttle. It feels like car stops accelerating for 1 second and then accelerates again. Sometimes the rpm falls about 50-100 rpm during that stage. All this makes me blame the torque converter. I changed the EGR pressure converter, MAP sensor, checked all vacuum hoses in the hope its the engine doing that.

Funny when I changed the transmission fluid, it didnt smell burned, the level was OK, no leaks, the temperature is OK also measured during normal operation (no overheating).

If I give full gas it pulls ok. I am just thinking if I should start investing money or leave it as it is.

[glitdi]

Check your idle speed... Engine might not be turning fast enough to activate the stator and create torque multiplication stage... If that doesn't help, take it to someone who knows how to do a stall test... You may have a free wheeling stator but they are pretty reliable, so I doubt it.
Also are you sure you used the right transmission oil?

[vladmury]

The idle speed is 730 rpm. The transmission oil used is Lifeguard 6hp.

[floydarogers]

I think everything the OP has described is normal.
1) These cars have rollback protection (using the ABS brake system) to prevent rolling back (or forward) when starting on hills.
2) The 6hp19 torque converter has a feature that partially disconnects when at a stop, to prevent load on the torque converter and to save fuel at idle.

Seems like a combo of torque converter lock, then unlock, and the rollback prevention is what OP is feeling.

[kbsilver]

Agree, sounds like normal operation. My car has always been like that in most cases once stopped, it will not move until you give it some throttle where the brakes release.

[glitdi]

Originally Posted by vladmury

The idle speed is 730 rpm. The transmission oil used is Lifeguard 6hp.

Bump up idle to 800 and see how it lurches forward.

[vladmury]

Actually I already did that, the old idle speed was 680 rpm and raised it to 730 rpm. DIS allows me a max increase of 50 rpm. Is there any other software that can be used to increase the idle speed even more?

[335dwanted]

I have found that when driving around in Sport mode and shifting the gears (so really full manual mode) that when I come to a stop the car stays in second gear and will not move much if at all by itself with foot off the brake pedal. If I manually shift to first gear the car will creep as expected while at idle with foot off the brake. Is it possible you are in second gear when stopped? I don't think the trans will start off in second gear in normal "D" mode.

[vladmury]

Yes the gearbox starts in 1st gear normally.

[OmahaDZL]

When you say you checked the vacuum lines....be a little more specific...

I wont say that my issue was exactly this...but it seems to be symptomatic of the behavior I got when my changeover valve wasnt functioning correctly.

In my case, the vacuum reservoir had an issue and the changeover valve was never fully closing.....ie...the small turbo wasnt getting full exhaust pressure at low rpms...and at the changeover point, it wasnt changing over efficiently.

I would check the vacuum in and out of the reservoir... if you have Rheingold, there is a procedure to continuously activate it while you check shit.....it works great and allowed me to find the problem my "mechanics" were not able to find.

[wissiin]

Hello,

Any updates? Did you fix your problem?