I am still having issues with my ASZ vrs.

1.Mpg is crap standard or mapped.

2. Gutless above 3000rpm in 4th gear or above stuggles to get to 4000rpm.

3. Sounds higher pitched no nice low rumble from exhaust.

4. Absolutely no black smoke under any load at any revs, regardless of map.

Now a bit of background. I ran a dtuk tuning box for around 12 months on the car. With this box it flew, but coughed out quite a bit of black smoke at higher revs like so many do. It over time gradualy stopped smoking to none at all. I can drive it round for a week and the back is clean. Great some of you may say but its not right. i remeber when it went right the back was pretty sooty after just one reasonable run. I removed the dtuk box some time ago and got a proper map, but as the car is not right in the first place i cannot expect miricles from the mapping. Main problems lack of poke and bad mpg.

Things i had done to try and remedy this :

1. New Maf.

2. New oem air filter

3 New coolant temp sensor.

4. Cleaned EGR.

5 Timing belt done by dealer with readout of timing and sprocket angle (call me paranoid).

6. Scanned with vcds, no faults

7.Logged with vagcom, maf readings fine, boost actual vs requested fine.

Which leads me to the catalyst converter, could the tuning box i had previously have blocked the cat?. Could a garage tell me if the cat has blocked or collapsed?. I do get more diesel odour in the cabin on starup now too. Sound like it could be exhaust related? The car is low mileage and looked after regular oil changes and ticks over at 882 rpm without missing a heartbeat. I dont really want to lose the cat but the a new oem cat is expencive. Thank you kindly in advance for any help.

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Edited 21 January, 201313 yr by RAPTURE

Take the cat off, you have nothing to lose as it will still pass the MOT. I had the same problem when I first got mine; I removed the cat, hollowed it out then refitted it and it cured the problem. I also used the 'Mr Muscle' trick to clean the turbo at the same time so one of the two, if not both, worked well and cost less than a tenner.

Hope this helps.

Best way to check is to whip it off and have a look.

If it's block just bash it out with a metal bar or simialr and then refit.

Phil

Would removing the inners of the cat put a light on the dash?. ASZ.

Nope!

I have in the back of my mind that having no cat/a hollowed out cat can cause over spinning of the turbo... not sure how right that is?

Phil

Also heard this but have no facts about it, any exhaust / turbo specialists got any more info on the subject.

Im pretty sure theres info on here of people mapping cars then decatting AFTER the map, resulting in overspooling. As long as the map is done with no cat in place it'll be fine.

I remember on my old Volvo 440 the Cat basically melted and blocked due to a slight engine misfire (so I was told).

When it did block the car all of a sudden started to chug and judder until it would not accelerate and the engine cut out. After that it just wouldn't start 'coz it couldnt breathe. Smashed it through when I got the car home and it was fine.

However... Before you get happy with the metal bar and sledgehammer (which i found quite theraputic) it would be worth disconnecting to see if the car runs better first!

My cat was blocked but i fixed it, took me a few weeks

I am still having issues with my ASZ vrs.

1.Mpg is crap standard or mapped.

2. Gutless above 3000rpm in 4th gear or above stuggles to get to 4000rpm.

3. Sounds higher pitched no nice low rumble from exhaust.

4. Absolutely no black smoke under any load at any revs, regardless of map.

Now a bit of background. I ran a dtuk tuning box for around 12 months on the car. With this box it flew, but coughed out quite a bit of black smoke at higher revs like so many do. It over time gradualy stopped smoking to none at all. I can drive it round for a week and the back is clean. Great some of you may say but its not right. i remeber when it went right the back was pretty sooty after just one reasonable run. I removed the dtuk box some time ago and got a proper map, but as the car is not right in the first place i cannot expect miricles from the mapping. Main problems lack of poke and bad mpg.

Things i had done to try and remedy this :

1. New Maf.

2. New oem air filter

3 New coolant temp sensor.

4. Cleaned EGR.

5 Timing belt done by dealer with readout of timing and sprocket angle (call me paranoid).

6. Scanned with vcds, no faults

7.Logged with vagcom, maf readings fine, boost actual vs requested fine.

Which leads me to the catalyst converter, could the tuning box i had previously have blocked the cat?. Could a garage tell me if the cat has blocked or collapsed?. I do get more diesel odour in the cabin on starup now too. Sound like it could be exhaust related? The car is low mileage and looked after regular oil changes and ticks over at 882 rpm without missing a heartbeat. I dont really want to lose the cat but the a new oem cat is expencive. Thank you kindly in advance for any help.

.

Im having the same problem as you after my revo, I thought it was a boost leak, had a new cam belt, new turbo because I had the standard rubbish KKK which blew, now a garrett one, always serviced. I thought it was the vacuum box but after doing some tests with VAG.com it appears my boost pressures are low, yet i have no boost leaks and my duty cycle is showing around 30-50 which apparently is low....ive been told it should be around the 80 percent mark. All of this indicates possible restriction eg the cat, so going to smash it though sometime soon and see what happens. Ill let you know

have you got VAG.COM, could you do some tests and see if our results are similar to mine

just so you know, miltek do a de cat for £170 quid, plus if you take your old cat back to a scrappie you will get 40 or 50 quid scrap value for it

ok, update......

took the cat off, smashed it about a bit using a sledge hammer handle until i saw light coming through it.....put it back on and WOW.....my car has never had so much power!! and mpg is back up to the late 50mpg instead of 40s.....

honestly mate, you had the same issues as me and now ive done this you will notice a huge difference