Neil205 1 Posted August 4, 2016 Recently purchased another GTi , 1.9 K Plate so has a cat on it , the owner had been informed that the car needed a new AFM , I removed the AFM and opened the plastic cover on the top , the carbon track didn't look that worn really , so not sure that this is the issue before I get it Refurbed . I've changed all service parts , and checked for any air leaks in pipes . Any ideas what else I could look for ? Share this post Link to post Share on other sites
Miles 331 1 Cars Posted August 4, 2016 Timing, Leak down test, Diag light on at all? Share this post Link to post Share on other sites
petert 587 Posted August 5, 2016 Does that mean it's Motronic? Share this post Link to post Share on other sites
Jon_Bmw 13 Posted August 7, 2016 Cat broken up and partially blocking the gas flow? Share this post Link to post Share on other sites
2-Pugs 57 Posted August 7, 2016 (edited) Is the distributor (not a distributor but just a casing) centrally positioned? Edited August 7, 2016 by 2-Pugs Share this post Link to post Share on other sites
mhyphenl 10 1 Cars Posted August 8, 2016 Could be that it's a cat model and therefore not as grunty as others!? Share this post Link to post Share on other sites
Neil205 1 Posted August 8, 2016 When you say timing what am I looking to adjust ? The cat is probalary original on the car , car has only completed 62,000 miles genuine .. Distributor cap is the Black Ducellier type held by 2 screws ? Share this post Link to post Share on other sites
mhyphenl 10 1 Cars Posted August 11, 2016 You can't adjust the timing. As 2-pugs has said, the distributor is an empty tube with a shaft through it and a couple of seals to keep out the oil, it just turns the rotor arm round the distributor cap. The timing is all handled by the Motronic ECU using a Crank position sensor next to the flywheel (mounted in the gear box). You can't adjust the mixture either, again it's the ECU, AFM and Lambda combination along with engine temperature sensor. As I've been finding out with some difficulty, this system only works well with everything in tip top condition, it will put the K light on if anything is out of line and in my experience this is very sensitive to any sensor faults or air leaks etc. As was asked earlier, is your K light on? It should light up and stay on with the key turned to second position, when you start the engine it should go out after a couple of seconds and stay off! If it comes on again after a minute or so or stays on after starting you've got an issue! If it doesn't come on when you turn the key along with the stop light, oil pressure light etc then the bulb has blown or has been removed!!! (cheeky!) Share this post Link to post Share on other sites
Neil205 1 Posted August 11, 2016 I've been reading up as well and like you say the timing and fueling on these is adjusted by the ECU . I started the car at the weekend and noticed the K light on and once engine starts it does go off and doesn't come back on . So if it is the AFM needing replaced this is technically working but not enough to trigger that light ?? If the cat was faulty it would trigger the light wouldn't it ? I'm thinking of replacing the exhaust as in places it's quite rusty but not leaking or blowing as far as I can see Share this post Link to post Share on other sites
Miles 331 1 Cars Posted August 11, 2016 The AFM's on these car's rarely give any issues at all unlike the Jetronic car's to the extent on Mi's (Same thing) they hunt at idle and when fitted to a 8v all is good, the main thing I've seen with these is the Carbon canister valve going wrong which brings the diag light on, but its dead simple to read the codes and the stored ones as this can help. If the Cat was removed it would run without any problems bar MOT time, but worth checking the chassis number to see if you can get away with it, the pattern CAT's restrict power quite abit and fit is very poor from euroflow Share this post Link to post Share on other sites
petert 587 Posted August 11, 2016 The Motronic is heavily reliant on the O2 sensor. In addition to checking what the error code is, that would be my first pick. Share this post Link to post Share on other sites
mhyphenl 10 1 Cars Posted August 13, 2016 the pattern CAT's restrict power quite abit and fit is very poor from euroflow Sorry ti Hijack, I know this doesn't relate to Neil205 issue. Miles, what issues have you had with poor fit cats? I think my issue may be this as I've now fitted 2 manifold to exhaust kits because of blowing and it's still doing it!? Share this post Link to post Share on other sites
Miles 331 1 Cars Posted August 13, 2016 The D/P sections have not lined up and the flow of the CAT is poor to say the least, it's like taking off 10bhp from the engine, But a OE Cat isn't cheap or find a Xsara/306 and weld one of those in Share this post Link to post Share on other sites
camgti 56 Posted August 14, 2016 All out late 205 gtis in OZ are the CAT versions. Definitly check the O2 sensor and also the coolant tenp sensor and make sure these are working well. The cat will be duff after 20 years. As miles said, if your going to replace it replace it with a later type. Share this post Link to post Share on other sites
