Joylove Posted February 1, 2008 Report Share Posted February 1, 2008 Today the CAT light began blinking on my dash, and more worryingly there was serious juddering in the engine towards the end of my run. Now, lights on a dashboard I can cope with, but is the juddering computer induced? What is the dashlight doing lit - detecting an excessive number of toxic gases after the CAT? I ask because if I have to replace the CAT, will I need to have the ECU reset too? Can I disconnect the sensor to remove the juddering while I travel to the garage? I don't have VAG-COM. Link to comment Share on other sites More sharing options...
Ska Posted February 1, 2008 Report Share Posted February 1, 2008 When you say reset do you mean erasing any fault codes? If so then you would need VAGcom or equivelent to clear but fixing the dud component should get the car working normal again; might also be worth checking your Lambda sensors too if its juddering Link to comment Share on other sites More sharing options...
Joylove Posted February 1, 2008 Author Report Share Posted February 1, 2008 What I mean is, if I go and cut in two new Powerflow Cats, will the ECU decide everything is OK and stop the buffoonery? On the VAGCOM side, I have a MY1995, and my USB ODBII device doesn't connect. I think I need a genuine RussTech device, can someone confirm? I am using V702 VAGCOM on Vista, could that be the problem? Would an older version on XP get me going? Link to comment Share on other sites More sharing options...
Ska Posted February 1, 2008 Report Share Posted February 1, 2008 I'm not sure about after market Cats, but I suppose ECU will do what ever the O2 sensors say after the new cats are on. The latest release is Vagcom704 which I run on XP but problems with connectivity and third party interfaces have been known. Link to comment Share on other sites More sharing options...
Joylove Posted February 1, 2008 Author Report Share Posted February 1, 2008 Thanks, I'll give it a go on my PIII 900MHz XP machine tonight. :? Link to comment Share on other sites More sharing options...
LostKiwi Posted February 1, 2008 Report Share Posted February 1, 2008 The '95 is not OBD-II aas far as I'm aware so yes VagCom is needed. Link to comment Share on other sites More sharing options...
Joylove Posted February 1, 2008 Author Report Share Posted February 1, 2008 I just hope someone can clear up if VAGCOM is hardware, or software, or both? Link to comment Share on other sites More sharing options...
alantong Posted February 1, 2008 Report Share Posted February 1, 2008 VAGCOM is both hardware and software. Standard advice for CAT warning is to fill up with optimax or other high octance / quality fuel and go for a blast. This may help if the problem has been caused by crap fuel etc. Alan Link to comment Share on other sites More sharing options...
Joylove Posted February 1, 2008 Author Report Share Posted February 1, 2008 On the way home, the CAT light went out and the juddering stopped. Do we think it could be a sensor? Wouldn't a faulty sensor show up on the system check before setting off? Link to comment Share on other sites More sharing options...
ant Posted February 1, 2008 Report Share Posted February 1, 2008 mine came on the day for the first time, i'd been checking a few fuses beforehand gave it a wash took it for a spin and the light flashed up, pulled over turned the ignition off/on still there..... off/on again and its disapeered and hasn't come back since. Link to comment Share on other sites More sharing options...
IT_S8 Posted February 1, 2008 Report Share Posted February 1, 2008 Pretty sure that the juddering will be the engine firing on 7 or less cylinders. The Cat light comes on because the cylinders that aren't firing are passing unburnt fuel through the exhaust. Most likely cause is a dodgy coilpack in one of the cylinders. You'll find if you Vagcom the engine, it will show the same cyclinder(s) consistently. If the juddering goes on for a while, the ECU can start to shut down other cylinders to compensate, so you might start firing on 7, then it might drop 6,5 etc. It can feel really scarey and will feel to get worse. Stop car, switch off engine and the ECU resets, so it will at least start firing on all the cylinders it can. I had it happen on the M74 once. It went away for a few days, but came back. 1 new coil pack later and no reoccurance. Link to comment Share on other sites More sharing options...
Joylove Posted February 5, 2008 Author Report Share Posted February 5, 2008 Thanks to IT_S8 for correctly indicating the failed coil pack. Can anyone help identify the Europart/Bosch part number to replace? My Local independant garage has got in a part and it's the wrong one. I suspect they either have the wrong part number from VW (077905101?) or they got the description of the vehicle wrong with EuroPart. The car is a 1995 N reg 4.2 V8. Link to comment Share on other sites More sharing options...
Joylove Posted February 5, 2008 Author Report Share Posted February 5, 2008 Looked at this link, seems to be the correct part.... http://www.airflowmeters.co.uk/searchresultsbymanufacturer.aspx?txtManCode=077905101 Link to comment Share on other sites More sharing options...
Figure11 Posted February 5, 2008 Report Share Posted February 5, 2008 The part number I am geting from VAGCAT.com is: 077905101 thats for the ABZ,AEM,AGH, AEW,AHC,AKJ, AKG,AKH engines of which yours should be one. Mike Link to comment Share on other sites More sharing options...
Joylove Posted February 5, 2008 Author Report Share Posted February 5, 2008 Cheers dude. Here's to you :-D Link to comment Share on other sites More sharing options...
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