Audi/Volvo 2.5 TDI: Severe Shaking at 2500-3000 RPM

Hi,

I know that this topic has been discussed countless times. I've also spent hours searching through forums and posts. Unfortunately, no one seems to have the exact same problem as me.
I drive a Volvo V70 2.5 TDI with the 5-cylinder Audi engine, producing 140 horsepower.
'For some time now, the engine has been 'stuttering' and losing power in the mid-RPM range. The problem also occurs when I accelerate heavily for extended periods, such as when merging onto a highway. Up to about 100 km/h, it revs smoothly without any issues up to 4500 RPM.'
Sometimes I can drive faster than 120 km/h, sometimes only 100 km/h, without any jolting. The acceleration values are generally acceptable, but sometimes they feel a bit sluggish.
Reaching the maximum speed is no longer possible, as the problem reappears at or around 140 km/h.
If I intentionally provoke the 'jerking' for a longer period by using full throttle, the engine check light comes on after a few seconds. However, it turns off again after one or two days.
My first visit to Volvo resulted in the diagnosis: 'Fuel injection pump is defective or misadjusted.' The cost: unaffordable!!
At a Bosch service center I know, they referred to it as a 'needle lift valve.'
So: exchanged... without success!
The next diagnosis was: 'Mass airflow sensor'.
So: swapped again... again without success!
Now I'm going to replace the EGR valve, as that might be the next possible cause.
A possible defect in this component only became apparent to me when, upon stopping the engine, it made a 'rumbling' noise several times. However, this rumbling disappeared when I tapped the valve, and then reappeared briefly. Whether this is related to the problem is questionable.
In addition, the valve costs a whopping 167.00 Euros from Volvo!
The fuel consumption figures are quite acceptable at 7.4 liters, despite the automatic transmission and a weight of over 1.6 tons.
Unfortunately, I only have basic knowledge and am not a trained mechanic.
'Can anyone give me some tips that a TDI beginner like me can understand?'


Thank you for your help.

Klaus.

Hello, master.

I also own a V70, a 1997 TDI model with 220,000 km, including modifications like a chip tuning, and I've also experienced some minor problems.

"Question: Is your engine chipped? Or do you have a tuning box installed? Or did you even get a cheap tuning modification?"

How about Ruzz?

Is it a buzzing sensation that comes from a feeling, or rather from the back?

I wouldn't recommend using AGR (Abgasrückführung). I've mostly deactivated mine because the only benefit is that it reduces idling speed slightly, but otherwise it doesn't change much (and I even have a working valve at home!).

Okay, I would definitely check with Bosch. The Volvo itself can't do anything about the ESP system. I've had the fuel quantity adjustment calibrated three times before, and it doesn't cost a fortune, but I can't say for sure if it's the solution.

Try to find answers to the questions, until then.

Best regards, Uwe.

Hi,

Thank you for your post.

Well, mine now has 310,000 km on the odometer, all from long-distance driving.

Okay, so no modifications or anything like that. The only change made for cost reasons is a washable cotton air filter (wet filter) because there's a lot of dust and dirt out here in the countryside. I pay 30 euros every 5000 km for a replacement filter. There's some soot when accelerating, but it's within acceptable limits. If I really floor it, a huge cloud of smoke comes out and obscures the entire highway.

The humming was definitely coming from the solenoid valve. I fiddled with it a bit. It's mounted on rubber bushings.

I've now ordered a used one. It costs 30 euros and has only 118,000 km on it. I'll probably give it a try. If it doesn't work -> Oh dear!!! The cost...

Thank you.

Hi,
You could simply try sealing the AGR (Abgasrückführung) with a metal gasket.
I suspect the problem might be related to a contact issue with the needle lift injector. It would be best to directly measure the resistance from the control unit to the injector's connector.
It could also be the boost pressure sensor or its connecting hose.
It was routed so cleverly in my car that it had to connect to the exhaust manifold via the connecting pipe to the EGR valve.
Has a mass airflow sensor already been installed in the Volvo? My Audi still has the "older" version, which is a volume flow sensor. They are actually quite reliable. However, even with these, the connections can sometimes cause problems.

Regards,
Olli.

Hi Olli,


Thanks for your tips, but I've already replaced all of that. The NHG is brand new.
The LMM (likely referring to a mass airflow sensor) has also been replaced with a working used part.
I'm going to replace the solenoid valve on the EGR system. If that doesn't fix it, I guess I'll have to take the car to a Bosch specialist.

Ich Tippe langsam auf Einspritzpumpe, bzw. Mengenstellwerk. That's going to be expensive!
Perhaps I'll even try fixing the signal box myself. Here's a great description posted about the repair, with pictures and everything. Kudos to the person who posted it!
Well, with 310,000 km on the odometer, things are bound to break down occasionally.




Klaus.

Perhaps air is being drawn in. If the problem only occurs after a certain amount of time under heavy load, the fuel tank ventilation system is suspect.

It could really be the fuel injection pump. It was also defective in my old Audi. You can have it repaired at a Bosch service center, which is cheaper than buying a new one (about half the price).
Greetings.