Engine management light coming on!

[s3nick]

Has anybody had their engine management light come on after using 100cell sportscats with sports exhaust for a couple of thousand miles or so?

I heard the lambda probe after the cat causes this is this true?


>> Edited by s3nick on Wednesday 19th April 10:45

[andrew medway]

I looked into getting a 100 cell system for my 996 TT. One of the things that was mentioned is that the 100 cell cats don't work properly after a short time. They simply wear out quick.

Don't know if that has happened to yours, but maybee.

[Don]

When my car was new Porsche replaced the lambda sensor THREE TIMES - symptom was the engine management light coming on.

Eventually they replaced the exhaust and the problem never recurred.

[rods]

s3nick said:

Has anybody had their engine management light come on after using 100cell sportscats wit sports exhaust for a couple of thousand miles or so? I heard the lambda probe after the cat causes this is this true?

Yes Nick the lambda sensors are very fickle,they need to be fitted exact,also check all the wires have been clipped back in their corect placings.

Management light can be reset,leave ignition in position two,disconnect earth from battery for two mins,reconnect earth,turn ignition off,take key out,turn back on.
Management light should be out.

[Raven Flyer]

Cars, since 2000, have had Cat efficiency routines. There will be a wideband lambda sensor(s) upstream of the cat and a trditional lambda downstream.

The ECU sends rich pulses and looks at the dip in the voltage on both sensors, plus the time delay between them. It then determines if the cats are working efficiently.

You can buy electronic boxes that fool the ECU into thinking the cat is still efficient (search for Code 0420), but if it fails the ECU test it will also fail an MOT and roadside test. These boxes are around £50 and go inline with the second lambda. They are safe as this lambda isn't used for fuelling.

100 cell cats are fine for racing, but there is so little precious metal in them that they won't last long at all. Especially if you have an ECU heating the daylights out of them (through the EGT) to get them working quickly.

[s3nick]

I spoke to Steve@Jz Machtech yesterday and he said this would happen because of the 100cell race cats, because after a while of using them they start to not work properly and give false emissions so the engine light comes on but it can be sorted out by having a remap.

I just dont want the hassle of this happening!

[Raven Flyer]

s3nick said:

I spoke to Steve@Jz Machtech yesterday and he said this would happen because of the 100cell race cats, because after a while of using them they start to not work properly and give false emissions so the engine light comes on but it can be sorted out by having a remap. I just dont want the hassle of this happening!

LMFAO

A £40 box that clamps the return values of the rear O2 sensor will fix it. The emissions aren't false, they are true. They are outside the accepted range and that's why you get a 0420 error code. Put simply the cat isn't working well enough.

Reflashing the ECU to re-set the trigger threshold on the cat test is a bit extreme and probably more than £40. I'd buy one of the boxes.

[grant3]

I have had a 100 cell (cargraphic- TUV approved)set up for the last 11k miles/2 years with no problems (He says fingers crossed, touching wood)2 MOT's ok, no engine lights, lots of great sound track & extra grunt!

[ballcock]

rods said:

s3nick said: Has anybody had their engine management light come on after using 100cell sportscats wit sports exhaust for a couple of thousand miles or so? I heard the lambda probe after the cat causes this is this true? Yes Nick the lambda sensors are very fickle,they need to be fitted exact,also check all the wires have been clipped back in their corect placings. Management light can be reset,leave ignition in position two,disconnect earth from battery for two mins,reconnect earth,turn ignition off,take key out,turn back on. Management light should be out.

Showing my ignorance but ... Lambda sensor position? .. It would have to politely introduce itself to me before I would recognise it!!

[t urbo]

grant3 said:

I have had a 100 cell (cargraphic- TUV approved)set up for the last 11k miles/2 years with no problems (He says fingers crossed, touching wood)2 MOT's ok, no engine lights, lots of great sound track & extra grunt!

Im running 100 cell cats too with no problems. I also know someone whos been running a fabspeed with 100 cell cats for our 30,000 miles and no problems.
Not sure the 'they dont last long' theory is particularly true.

[Derek-6jyv6]

I know this is an old post but just wondering if there is any update for the fix on this whether it is the black box that has been mentioned or something else that might be on the market. Thanks

[Pope]

As discussed earlier in the thread; if the issue is after cat/cat efficiency most issues can be addressed using stand-offs; the after cat sensors are effectively moved out of the full exhaust stream and won't trigger the CEL threshold.

Something as simple as this:

https://www.amazon.com/Pack-Sensor-Spacer-Adapter-...