[RoyC]

Hi folks, for reasons unknown my 159 suddenly started to sound like a tractor below 2,500rpm. Once I hit that magic number everything seems to smooth out and she's lovely again.

Performance doesn't seem to be affected though maybe she's a little down on power at low rev's - could be me though.

Can anyone explain to me what happens around that rev point? I know there's some trickery with the EGR system but I'd love to know more.

Thanks

 

[halftone]

Swirl valves fully open, egr closes, turbo boost begins all around 2000-2500 rpm.

 

[giblets46]

Likely the EGR, but could be other issues,
Have a read through the following, many of them are retry easy to diagnose, after that it can get more difficult! :

http://www.alfaowner.com/Forum/showthread.php?t=367560


Any spelling/ grammatical errors are purely there to annoy!

 

[RoyC]

Likely the EGR, but could be other issues,
Have a read through the following, many of them are retry easy to diagnose, after that it can get more difficult! :

Power Loss with Diesels: Guide - Alfa Romeo Forum


Any spelling/ grammatical errors are purely there to annoy!

Thanks to all for the responses.

EGR valve has been changed for a new one since this trouble began so I doubt it is that. The old one actually works ok and didn't have a lot of soot in it anyway.

Noticed this morning what sounds like a metallic rattle. Sounds like two bits of sheet metal clattering against each other. Given that 99% of my driving is in-city and I usually get the limp mode/blocked DPF every couple of months but haven't since this problem began, I'm wondering if the exhaust pipe to the EGR has broken or split.

Hopefully I'll get time this weekend to get under the car and have a poke about. Also need to get the EGR blanking plate in.

Any other ideas you guys might have would be gratefully received!

Cheers

 

[Leo_NL]

Check your oil level and pressure first. Especially if you can't detect a suspicous heat shield or similar thing causing any rattling sound from outside of the engine.

 

[halftone]

Is this a 1.9 16v CF4?

 

[RoyC]

Oil level and pressure are ok - according to MES.

Yes, this is the 16v 1.9 JTDM. No idea what a CF4 is though!

Thanks

 

[Cuore_Sportivo_155]

cf4 = euro4 emissions level engine.

 

[halftone]

CF4 has an inlet manifold that appears to be made of black plastic rather than aluminium of the earlier 1.9's and all 2.4's. They have a nasty habit of shedding the metal swirl flaps into the engine (see my avatar pic), and your loss of power and mechanical clatter is suggestive. Unfortunately there is no way to tell whether this has happened, by visual inspection, although a compression test would show damage such as bent valves.

Autolusso - Swirl Flap Delete

Mega-thread DIY
http://www.alfaowner.com/Forum/alfa...s-how-and-maf-clean-how-anywhere-159-1-a.html

 

[RoyC]

Yeah, I did wonder about a dropped swirl flap - what a dumb idea these are!

Although mine is on an 09 plate, it appears to have an aluminium inlet manifold.

Weather permitting, I've finally got some time free tomorrow to have a play with the car !

Cheers.

 

[Autolusso]

Yeah, I did wonder about a dropped swirl flap - what a dumb idea these are!

Although mine is on an 09 plate, it appears to have an aluminium inlet manifold.

Weather permitting, I've finally got some time free tomorrow to have a play with the car !

Cheers.

Being a 09 car it won't have the aluminium manifold unless someone has changed it

We see loads of these engines with swirl flaps going in to the engine, have 2 in the workshop today

Ned

 

[RoyC]

Being a 09 car it won't have the aluminium manifold unless someone has changed it

We see loads of these engines with swirl flaps going in to the engine, have 2 in the workshop today

Ned

Youch

What are the initial symptoms, Ned ?