Peugeot 406 judder at around 1400-1600 RPM

[MyPug]

I have a judder/stutter/jerk at around 1400-1600 RPM. Above and below this RPM it is running fine. Blanked the EGR valve completely off with a solid plate. No fault codes came up and its been like this for years now. Starts and runs fine. Diesel filter replaced at intervals. No fault codes. Been to diesel specialist and numerous experts over the years to no avail. Any solution to this problem will be much appreciated. Thanks.

[Doggy]

Likely to be a sensor issue or bad connection - do you have access to PP2000?

[MyPug]

Thanks Doggy. Unfortunately I do not have access to PP2000 or any other code readers. But my local Peugeot dealer has and they have run numerous tests and found that all of the sensors "are within specs" So I took it to a Diesel specialist. They concluded that everything is fine, despite the Pug stuttered like it wanted to be payed to run when the technician took it for a test drive with a laptop connected to the 406.

[Doggy]

Try disconnecting the MAF, (mass air flow sensor).

Can't be sure, but I think it should drive OK without it, (HDi 110's definitely do but 2.2 HDi's won't).

[GingerMagic]

Hmmmm

Normally I would suggest the fuel pressure regulator, which is on the fuel pump, but I'm not sure the Siemens has this....

Have you tried driving with the MAF sensor unplugged?

Also, it's worth cleaning out your throttle position sensor, as it's sometimes overlooked, but can play up.
There is a guide to this on the forum somewhere.

If none of the above seem to work, could it be down to worn engine mounts?

Edit - Doggy beat me to it re the MAF.!

[MyPug]

The Siemens 5WS40018 fuel pump have a Pressure Control Valve (PCV) and a Volume Control Valve (VCV) according to info I found in Siemens product catalogue for the pump.
Part number is:
1933.41 - Common Rail Fuel Pump Pressure Regulator
1933.43 - Common Rail Pressure Regulator VCV Valve
I hope this is the correct number for the pump.

[MyPug]

Thanks GingerMagic and Doggy. I have cleaned the MAF sensor with appropriate cleaning spray. I have not tried to run it disconnected. I will do that.

GingerMagic; throttle position sensor is a good idea. That makes sense for the constant RPM. Worn engine mounts is another thing I have not thought about. I'll have it checked.

The only solution offered from my dealer is to replace the pump.

[MyPug]

I will report back as soon as I have tried these new suggestions.
GingerMagic and Doggy, many thanks for your input. It is very much appreciated.

[MyPug]

I have disconnected the MAF sensor, no change.
The engine mounts are fine.

Could it be the injectors?
Siemens part number 5WS40000-Z.

[PeterN]

I haven't personally found that it makes a lot of difference whether the MAF is connected or not. I have had problems with the pressure sensor on the back of the HP pump causing all sorts of problems. There is a very fine filter on them which clogs up, I haven't successfully unclogged one but its worth trying a secondhand one.

Peter

This onehttps://www.ebay.co.uk/itm/174262209438?hash=it ... SwXmpepOow

[MyPug]

Thank you Peter.
Do you mean the Pressure Control Valve (PVC)?
Sorry if this is a daft question.
The eBay link you kindly provided shows an image I am unable recognise.
The sensor I have a picture of is somewhat different. It has part number 1933.41.

I'll start with replacing the sensor with a new one, since this is what most people recommend.

[GingerMagic]

I was looking at the Knowledge Base to find you a topic of how to clean the throttle sensor, but came across this....

viewtopic.php?f=10&t=12414

Have you checked your in-tank strainer?
It's not something I immediately thought of but worth a butchers.

[MyPug]

Thank you GingerMagic for the tip.

I'll take it out and have a look.
Didn't see the pictures in the "Diesel flat spots" topic, but I get it.
Another ting mentioned by my local Pug dealer is that the clutch on the alternator is failing and that it could cause judder. It is up for a replacement anyway.

I use diesel additives on regular bases in the hope it will keep the fuel system clean.

Thanks for all the inputs.

[PeterN]

The high pressure fuel pump that supplies the common rail. You will have to remove the fuel filter to get to it but its only held on by two screws and a connector.

Peter

https://www.ebay.co.uk/itm/174262209438 ... SwXmpepOow

[MyPug]

Peter, this Pressure Control Valve is what I fund that has the correct number, 1933.41:

https://www.ebay.co.uk/itm/174650802627 ... SwZsRgNcxO

How can I tell if it is made in a country with questionable reputation?

Many thanks.