E320 W210 Loss of torque after slow driving

[Smaltze]

Hi guys,

Got this anoying and ever more common problem with my w210.
when i drive the car normally it goes like a rocket, and if i keep putting my foot down at every oppurtinity it kicks down and blasts off, head back. great.

But recently often it has this problem that seems to occur only after i drive slowly and steadily for a while. such as slow motorway cruises or in slow traffic.
When i put my foot down there is barely any response, it accelerates but only very slowly, creeping up the revs. when it reaches higher revs it starts to pick up a bit.

If i press hard it will downshift, but its still very limp and nowhere near what i expect.

When i restart the car at a set of lights or something its fixed, back to normal, atleast for a few minutes until i drive slowly somewhere again and it goes limp.

Now like i said, if i drive like a nut the whole journey it tends to stay fine. only happens after periods of slow driving as far as i can tell.

Any ideas? tried searching around.

 

[alexanderfoti]

Your car is going into limp home mode. Likely due to the EGR as that only gets actuated at idle and part throttle loads.

Get it on Star diagnostics to confirm. If it is, fit the EGR shunt detailed on this forum rather than replacing the valve.

 

[Smaltze]

Your car is going into limp home mode. Likely due to the EGR as that only gets actuated at idle and part throttle loads.

Get it on Star diagnostics to confirm. If it is, fit the EGR shunt detailed on this forum rather than replacing the valve.

Most places around me charge a bomb to get it on the star diag.
could i just do the egr shunt anyway and hope it works?

 

[toby1]

Assuming it's a diesel then I'd have the codes read as well. Wayne Gates is in north London and they know what they're doing.

 

[Smaltze]

Is there any videos of the egr shunt somewhere?
I feel im sufficiently able, but havn't done a job quite like this before, and am fairly new to the car so not entire clear what needs to be done, having looked at the picture tutorial.

 

[jp williams]

Is there any videos of the egr shunt somewhere?
I feel im sufficiently able, but havn't done a job quite like this before, and am fairly new to the car so not entire clear what needs to be done, having looked at the picture tutorial.

Toby has given you the best advice. Wayne Gates (Terry) is highly thought of and won`t rip you off.

Regards

John

 

[alexanderfoti]

There aren't any videos that I know of. It could be many many things, so as others, I would get the codes read first.

 

[Smaltze]

ok an update.

I took off a piece of the egr, the round cylinder like bit held on by 3 screws, has a spring contraction thing in it. it was completely full of black soot. i cleaned it out, but it was moving fine anyway. Put it back on and it didnt make much difference. not sure which part it is.

anyway a more major update is a battle ive been having with a very loud blowing like sound. I recently put a straight pipe on and for ages i thought it was blowing but i couldnt find anywhere that it was. The loud sound im getting is defintely not just because its straight piped. its practically the same as when its backboxed when its working properly, just revs louder on foot down.

It often happens when im idling at a junction or something, it will be quiet then very noticably it will sortof 'switch' on and the exhaust sounds way louder and bassy and reverberates massively. when i accelerate you can feel it through the whole car and its rather unbearable. it makes a loud gargle like sound from the exhaust with the windows down, much more throaty. almost 'wet' like sound if that makes sense?

Today i realised this sound is definetely linked to the limp home effect im getting. because driving today as soon as the sound turned on the car instantly felt in the limp mode. and when i restarted the car soon after the sound completely went and so did the limp home. i really need to fix both the sound and the limp home because both are annoying and unbearable.

 

[alexanderfoti]

Yes the exhaust note changes when its in limp home mode as it changes into a safety engine map. Its more noticeable with a straight pipe.

EGR valve codes aren't always related to EGR valves. The pipework leading from and to the valve through the inlet manifold can block up with crud too.

You really need to get the codes read or you will be guessing with various parts.

 

[Steve@Avantgarde]

Sounds like a split turbo pipe to me....or one which has fallen out the intercooler, hence the intermitant nature of the fault. When it seals it will go like a train (likely due to the mass suck in the induction system from hard throttle) but on light throttle and no induction suck the pipe falls away and the actual values then read a loss in charge pressure as it cant build up boost quick enough on demand.

 

[Smaltze]

Sounds like a split turbo pipe to me....or one which has fallen out the intercooler, hence the intermitant nature of the fault. When it seals it will go like a train (likely due to the mass suck in the induction system from hard throttle) but on light throttle and no induction suck the pipe falls away and the actual values then read a loss in charge pressure as it cant build up boost quick enough on demand.

Interesting, why would this be fixed by restarting the car though?

Alex's explaination, ie it going into limp mode fits as the sounds it directly linked to the slowness.

Then again i suppose the sound could be the turbo blowing?
im definitely going to check this out either way, as its quite possible considering how many times ive had the upper part of the exhaust off and could have wrenched it somehow.

 

[Smaltze]

Fitted the Egr shunt today, seems to have fixed it. Nice one Alex

 

[mck.]

Fitted the Egr shunt today, seems to have fixed it. Nice one Alex

Hi everyone, I see I have the same problem, but in year 2023
Some tuners told me that i just can take car to any tuning shop and they will "delete" EGR valve and I wont need the shunt

 

[alexanderfoti]

Hi everyone, I see I have the same problem, but in year 2023
Some tuners told me that i just can take car to any tuning shop and they will "delete" EGR valve and I wont need the shunt

Yes this is a cleaner way of doing it.