2.5TD Exclusive - loud buzzing from OSF

[andmcit]

My black 2.5 is planned to be pressed back into service asap and whilst I'm yet to tackle properly the AC belt issue,
one thing the car is fond of doing at the moment every time the ignition is on and / or the engine is running, is a
loud buzz from the front offside lower nosecone area beneath the headlight. First off, is it a stuck relay, and if so,
where is it and what is it trying to switch!? IIRC the car doesn't have cruise which I've seen lives there on a 2.1 I've
had a close prod about on; it's not something I've ever looked for or bothered about much before on this car and
as it's 50 miles away from me at the moment I can't do a physical check to confirm anything.

Question is, what do I need to expect / look for before getting the car brought back on a trailer and MOT prepared
and tested? Anything I need to specifically check? Where are the 2.5 drivers out there? Anyone heard from John
lately?

ttfn,
Andrew

[Dieselman]

Sounds like the EGR vacuum pump. If the car isn't fitted with a MAF sensor then just disable the pump and EGR system.

[robert_e_smart]

Anyone heard from John lately?

Nope, I noticed that he hasn't been posting for a while now.

Your 2.5, there is the injection double relay that sits on the outside of the ECU box if my memory serves me correctly from my brief dealings with my 2.5.

[andmcit]

Sounds like the EGR vacuum pump. If the car isn't fitted with a MAF sensor then just disable the pump and EGR system.

Please be kind to me - I'm a diesel unbeliever - petrol every time for me... )

Do you know Will, whilst I don't understand a single word of your answer, I seem to recall a similar reply
John gave a while back but I cannot recall the thread / context - may have been when the car belonged
to my pal before I took it on and I enquired out of curiosity about a faint buzz - it's a whole lot louder
now!

Give it time and I'm sure I'll be grappling with the innards of these like the rest of you diesel guys
and whilst I have an aversion to diesels I've been impressed by the 'petrolness' of the drive from
these 2.5's! Ok, so I own x2 of them, but as of yet haven't ventured into the "oily bits".
OK, EGR = exhaust gas recirculation I think I 'get' as a concept; the reality and MAF sensors I don't!!

Maybe a "Janet and John fix their Xm" will work? Not the XXXX rated version either!!

Just to confirm, the car starts on the button and idles well and revs / pulls OK too.
No aparent dodgy emissions or pinking. The double relay starts sounding like a petrol Robert - like it!!
I'll have a closer look but IIRC it's lower than the ECU box but the right area of the car.
God, show me a V6 or a 2.0i and I'M HAPPY.

Andrew

[Dieselman]

Anyone heard from John lately?

Nope, I noticed that he hasn't been posting for a while now.

I had also noticed.

[robert_e_smart]

He posted on the other forum about going away for a few days.

I think a nice 2.1 TD with a manual pump would be good for you Andrew. Nice and simple, no electronic control elements to worry about.

[Dieselman]

Please be kind to me - I'm a diesel unbeliever - petrol every time for me... )

Give it time and I'm sure I'll be grappling with the innards of these like the rest of you diesel guys
and whilst I have an aversion to diesels I've been impressed by the 'petrolness' of the drive from
these 2.5's! Ok, so I own x2 of them, but as of yet haven't ventured into the "oily bits".
OK, EGR = exhaust gas recirculation I think I 'get' as a concept; the reality and MAF sensors I don't!!

Maybe a "Janet and John fix their Xm" will work? Not the XXXX rated version either!!


Andrew

Ok, which do you want to be Janet or John..??

The EGR valve recirculates exhaust gas back into the intake manifold to reduce the volume of free oxygen thus reducing the amount of NOX (nitrogen oxide) at idle.
There is an abundance of free oxygen as there s no throttle flap to restrict the volume of air, thus all torque regulation is performed by adjusting the volume of fuel injected only.
The valve is operated by the vacuum pump under the o/s inner wing.

Later cars (post 98) use a MAF (mass airflow sensor) mounted just after the air filter box to determine how much air is being injested by the engine, thus can fuel accordingly.

[2point5XCL]

I agree with Dieselman the source of the buzz or hum is likely to be the EGR pump. My 2.5 makes the noise too but is barely noticeable when the engine is running so I haven't bothered to do anything about it.
John mentioned in one of his posts, maybe on club XM, that he would be away for about a week or so.

Roy.

[robertmnorton]

Hi all,i agree it's most likely to be the EGR vacuum pump.On BTE engines it is on the end of the camshaft,don't know if the DK5 had this fit.For info Andrew,the cruise vac pump,solenoid and regulator are in the n/s inner wing,the ecu in the ecu box.
robertm

[xmexclusive]

Hi Andrew

Virtually certain it is the EGR pump.
Can be seen/reached from the wheel arch with the liner out.
Leave it alone for now unless it flattens the battery or the noise irritates the hell out of you.

Sorry to be found missing.
Collected the latest 2.5 last week from Blackburn.
Trade car bought over the phone so using it for a weeks holiday was fun.
Took it North and toured the borders.
It managed 1500 miles without missing a beat.
SWMBO was duly impressed particularly that we did not breakdown on the Holy Island causeway.

John