weird power loss issue, maybe melted and blocked cat?

[Jimmy P]

Hi all i don't tend to post on here just research, I've done some looking with regards to my questions but yet to find any answers so here goes!

First a quick background on the car

2006 VRS

175K miles

new turbo @ 120k

SS style huge intercooler, custom silicon pipes.

EGR delete and with egr outlet blanked at manifold

Mufflerectomy around 2k ago

past MOT a few weeks back emissions where spot on.

I was driving home last night from a course, normal motorway speeds, boosting lovely as tested at previous roundabouts etc.

I came off the motorway and only a small carriage way, gently down on the speed, round a roundabout and gently back on the throttle (no hoonage)

Only to find no power, it wasnt a popped off turbo pipe, ive had enough of that to know the symptoms and how why and what that sounds like. the car runs fine but just doesnt pull anymore. The turbo sounds exactly the same as it always has, slight whistle on idle but thats normal.

Only thing that i can identify is from the back end its got considerably louder, only from the exhaust, now, past exploits in jap cars have led me into whipping off the cat, smashing out the contents and fixing the issue.

it sounds to me like this is the issue but i thought id pick you guys brains!

Should it be the cat doing the dirty deed of slowing me down to a crawl what would be the best way of fixing it? I am NOT buying a new cat!! ha ha

Can you whip the downpipe off and knock the contents through?

or will i have the cut the box out and smash it through and weld it back in?

or will i have to cut the box out and weld in a straight pipe?

if so, what pipe diameter is the downpipe at the cat section, part of me wants to say 2.5"

Sorry for the essay

TIA

Jimmy

[fletch101]

If you can hear the turbo spinning over normaly . I would say that the cat is fine. Every blocked cat ive come across has chocked the engine to a stop

Maybe the car has went into limp mode. EML on ?

[Jimmy P]

Yea I see what you mean, since writing this I've got a reader on it, just a basic one mind.

Got the following codes

19586 egr valve (it's gone so expected!)

17058 glow plug loom

17911 load signal from the alternator

18097 powertrain databus implausible value

17564 map sensor

Now to me it could either be

Map sensor ****ed

N75 gone (it always has made a funny vibrating noise on turning engine off)

Or veins stuck (thergo over boosting, map reading out, limp mode)

First port of call map sensor.

The darkside ones on eBay ya know the "3bar" ones, is this an oem part? Can I get it cheaper than the £30 they charge? Pattern parts are £15 delivered

[sepulchrave]

It won't be the cat, turbodiesel exhaust gets nowhere near hot enough to melt one.

 

N75 or MAP sensor.

[spud31]

i would check the loom around by stater motor/ oil filter area, as most of these faults are wiring in this area

[fletch101]

Just try taking map sensor out and cleaning it with brake cleaner first. .. they get gummed up with oil . Especially when you srill have an egr