Will watch this with interest as mine does this from time to time .....sorry but I can't help !

 

Sounds like the EGR sticking open.

 

There is a pdf on how to clean the egr valve on this forum, its very helpful as I'm no mechanic by any stretch of the imagination yet I found it an easy thing to do with my 156. My car had the same issue but was a combination of the egr valve being clogged with soot and the small turbo vacuum pipe being split. I replaced the pipe and cleaned the egr valve and full power was returned. I was even pleased with the fact the engine management light reset itself.

 

Would a egr

Temp senser make it lagg bro

 

I'm getting a rather odd power issue with my GT (Diesel)

My mechanic changed a sensor (I can't remember what), saying this is what the computer reported, but this hasnt solved the problem.

an error code sometimes needs a bit of thought as to whats happening around it and how if affects it..
it could have been map sensor he changed
anyway it does sound like egr as said having gone through that on a 156.......bogs down then off like a rocket when revs get up.........but leaving a smoke screen behind!

 

I found out the name of the sensor my mechanic changed. "Air Mass PRessure Sensor". This was reported to him by the computer. It's been back in, EGR cleaned and still exactly the sameproblem remains.

 

yeah map sensor, these can be cleaned and rarely fail and i dont think that is or was your problem........like i said u have to think around the error.........incorect working vg mechanism in turbo will throw cause pressure to be wrong, i hate mechanics who cant think outside the box

 

My next thought if its not the egr would be the small vacuum tubes. They run from the vacuum pump at the rear of the engine to the front to the turbo actuator valve (cant think of correct name for it) from there it runs to turbo. Also a few more are in the mix are a couple more tubes but once you find the pump you can follow them to see where they go, also if removing hoses from vacuum pump care is needed because they do get brittle. The original hoses are hard plastic and can crack, if you lose vacuum in these pipes you get no turbo operation.
Most people replace them with silicon hose but not sure what size is required

 

Ok just been back to the mechanic and had him scan it in front of me. Engine management came back with two errors

p1237 Air quantity
p0704 Clutch switch circuit

Does this help shed any light on the problem with anyone?

 

As Maverick says, if you haven't done so then replace all the small vacuum tubing with 3mm silicone. Even if they look OK they could be split, a small hole will cause all sort of boost problems.

 

http://www.alfaowner.com/Forum/alfa-147-156-and-gt/284386-147-jtd-16v-lack-of-acceleration.html

 

If it is not smoking, I'd clean the MAF with electrical contact cleaner. I have had the MAF clogged with oil from a K&N and the ECU sees less air, so it fuels less and thus no power. 160bhp I had on the rollers, clean the MAF with a spray of brake cleaner and poof 230bhp. It didn't give any fault codes either.

 

egr also causes air issues as well !!

i love "mechanics" who dont know nothing and dont know how to analize codes !!!

 

The EGR generally causes smoking and EGR operation is determined via MAF changes, so a faulty MAF could give EGR fault readings. I'm not keen on people who don't know what they are talking about either but then I am a mechanical engineer not a mechanic and the EGR already having been mentioned, I offered ADDITIONAL options rather than squaking like a parrot.

 

Am wondering if this is the same problem as i have:

http://www.alfaowner.com/Forum/alfa-147-156-and-gt/365142-low-acceleration-power-and-smoke-at-higher-revs-gt-jtd.html#post5142578

Am gonna start looking at the turbo as suggested in that post yesterday, but it could be the same as this one.

 

could be the turbo control pipes with splits in them, then the ecu can not get the turbo in to high boost mode so you have virtually no boost untill 2500 rpm

if you can remove pipes and inspect under and eye glass, any splits - replace the lot with silcone, 2 quid a metre of ebay

 

Update: The MAF had already been changed as the mechanic was assuming it was this through the fault codes.

EGR route didnt solve anything and the pipes I've been told are fine and "already upgraded".

Lack of power still remains...

 

You seem to have covered all the usual culprits, next thing i would look at would be fuel delivery, fuel pressure rail and associated sensors and any fuel regulators maybe even the fuel pump. Apart from suggesting what i'd look at i'm sorry cant be of more help.

 

hi i have had same problem but think i have sorted it first bypass your pressure convertor where the 4mm pipe goes from turbo to black plastic thing (pressure convertor) and the other black pipe shoots off to back off engine connect them together with some tape but dont make it two air tight as if you do it will be flat your car should go very well if it does its your pressure converter hopefully. i am waiting on a post on this. also if that dont sort the problem check theres no splits in your pipes 4mm ones also the big turbo pipes plus clean egr valve and check if your needle moves inside and if thats ok i bet your veines are cloged in your turbo this was one of my problems a year ago after after cleaning it it went like a bullet
cheers mitch

 

stop doing that dip the clutch and rev it stuff cos dmf's and clutches aint cheap either

 

You can carry out a VNT test through the ECU that will pump the VNT duty and rev the engine at idle, then hold it there so you can check for leaks and the function of the system components.

 

Same problem as me and have traced it to the clutch switch , when I lose power I touch the clutch and it comes back , checked with multiecu scan and was showing clutch pressed when it wasnt