[avr]

Hi, my car is f31 318d N47 with rear-wheel drive only. The car has automatic gearbox, mileage 350,000 km.

I have read a lot of similar topics, but so far without any improvement, namely:



My problem is that when accelerating gently-softly, around 1200-1900 rpm, the car shakes and jerks slightly.

A slight jerking also occurs during constant speed on the cruise limiter control (if the revs are as specified above) - it manifests itself as follows: vibration for 2 seconds, 3 seconds of rest, vibration for 2 seconds, 3 seconds of rest and so on...





It does not occur at idle speed (gearbox P,D,R or N - speed 0)or during engine braking.

This does not happen during dynamic acceleration

This does not happen when I switch the gearbox to manual mode and, for example, at a speed of 70-80 km/h in 8th gear, I press the gas pedal to the floor and the engine has a heavy load.

This only occurs when you gently press the gas.

Changed egr to OEM, fuel pressure sensor on the CR rail, fuel pressure regulator in the injection pump (no metal pieces inside), fuel filter.

Fuel pressure set at full load = 1600 - in reality the pump turns up to 1560

Set fuel pressure vs real value during jerking = 1:1

Air mass flow set vs real value = 1:1

The oil in the gearbox was changed 40,000 km ago

Injection correction -0.3 +0.3

Unplugging the egr plug does not change anything

No errors in ista

[Eddamoo]

Im not sure what you mean by 'dynamic acceleration' but from the jist of your message it seems like the problem does not happen when the car is being requested around maximum power?

This sounds to me like it could be an closed-loop running problem probably caused by a lazy Lambda or MAF/MAP sensor. I say that as when a car is running at 100% it will move to open-loop running.

Closed-loop: Car uses sensors to measure running parameters to target maximum efficiency and minimum emissions.

Open-loop: Car uses pre-defined AFR tables to target maximum power. Partly because the sensors wont be able to keep up.

[avr]

Originally Posted by Eddamoo

Im not sure what you mean by 'dynamic acceleration' but from the jist of your message it seems like the problem does not happen when the car is being requested around maximum power?

I mean my problem exist when I press the gas pedal for 5-10%. When I press like 50% of pedal (to 100%) there is no problem. even at the same RPMs like before.

Originally Posted by Eddamoo

This sounds to me like it could be an closed-loop running problem probably caused by a lazy Lambda or MAF/MAP sensor. I say that as when a car is running at 100% it will move to open-loop running.

Closed-loop: Car uses sensors to measure running parameters to target maximum efficiency and minimum emissions.

Open-loop: Car uses pre-defined AFR tables to target maximum power. Partly because the sensors wont be able to keep up.

thank You for an advice. As i know the car has dpf and catalyst cut off. it wasnt make by me, so perhaps the lambda is be turned off?! how can I check it? by Ista?

MAF Logs in ista shows air flow same for required and achieved (in real) but for sure i will replace both sensors and check it.

[Allworth]

Have you checked engine mounts?

[avr]

Originally Posted by Allworth

Have you checked engine mounts?

Yes I did, also as I said, the problem does not occur at idle gear

[bishbosh]

Originally Posted by avr

My problem is that when accelerating gently-softly, around 1200-1900 rpm, the car shakes and jerks slightly.

These are the conditions where the EGR is normally activated. When you changed the EGR did you reset the adaptation for it? Can do this in ISTA.

Also, with the DPF/Cat removed, it's hard to work to a baseline as it depends how well the DPF/Cat was mapped out, if not done properly it can lead to issues.

Do you know if the EGR was mapped out?

[avr]

Originally Posted by bishbosh

These are the conditions where the EGR is normally activated. When you changed the EGR did you reset the adaptation for it? Can do this in ISTA.

Also, with the DPF/Cat removed, it's hard to work to a baseline as it depends how well the DPF/Cat was mapped out, if not done properly it can lead to issues.

Do you know if the EGR was mapped out?

Someone told me that my egr doen't need to be adaptated, because its mechanic system, not electronic one. Car is 2013, I am not convinced by this opinion.
egr valve in ista is 0,7. I will try to reset the settings.
also I disconnected the slot, plug of egr - nothing changed.

[avr]

Update. I did adaptation of egr, in Ista his value is 0,7 point. also i did reset of gearbox, air mass flow and fuel adaptation. Unfortunately didn't help

[McBeemer]

Are you in Australia by any chance ?

[avr]

Originally Posted by McBeemer

Are you in Australia by any chance ?

nope, europe

[bishbosh]

Might be expensive but the way I would go about this is to start from a clean sheet. So I'd fit a replacement DPF then map the DDE back to stock, only then can you know if the juddering is caused by a faulty map or not.

[avr]

I drove 100k km with this map (without dpf). Problem with jerking exist for few months. What You think?