Cel Light

After reading a thread on here I bought (for 25$ plus postage -- around £16 in all) a CEL "check engine light" eliminator from here www.o2sim.com. At first I thought it didn't work cos the accursed light came on again after about 40 miles, as usual, after a reset. HOWEVER after a further 100 miles it has gone out and stayed out ever since. So the device does work but it takes a while to settle down. With the NA vx 220 (and no cats) you need this to keep the management light off. If you have only removed the pre-cat you dont need it. The device (which comes with good instructions) simply splices into the second O2 sensor but you need to know that on our vehicle the two white wires are for the o2 heater (one is earth and one is 12v feed), black is feed to sensor and grey is signal return. Hope this helps those with no pussy in the pipe. Griffo

I have the same problem. This because the EMS "Washes" the cat every 40 miles or so by running momentarily rich. It then compares readings from the Pre / Post Cat Lamda sensors and makes an OBD record. The light comes on as "Low Cat Efficiency" - On mine this happens even with the exhaust CO's at 49 - compared to an MOT test top limit of 200. The bottom line is that it's just an annoyance and the engine is running fine (and cleanly). My car has a 200 cell sports cat - this together with the precat and standard backbox mods was worth 8hp. The cat cost £170 - the rest was just time spent. The risk of the light coming on is highest if the wash coincides with running at cruise power. Maybe the answer is just to go flat out everywhere !.

What sort of cat have you got and where from?

I have the same problem. This because the EMS "Washes" the cat every 40 miles or so by running momentarily rich. It then compares readings from the Pre / Post Cat Lamda sensors and makes an OBD record.

The light comes on as "Low Cat Efficiency" - On mine this happens even with the exhaust CO's at 49 - compared to an MOT test top limit of 200.

The bottom line is that it's just an annoyance and the engine is running fine (and cleanly). My car has a 200 cell sports cat - this together with the precat and standard backbox mods was worth 8hp. The cat cost £170 - the rest was just time spent.

The risk of the light coming on is highest if the wash coincides with running at cruise power.

Maybe the answer is just to go flat out everywhere !.

does it go off by itself after time (5 cycles) or do you have to reset it?

#2177

mine only comes on if i let the revs drop below 1000 rpm for more than 5 seconds or so ??

I have the same problem. This because the EMS "Washes" the cat every 40 miles or so by running momentarily rich. It then compares readings from the Pre / Post Cat Lamda sensors and makes an OBD record.

The light comes on as "Low Cat Efficiency" - On mine this happens even with the exhaust CO's at 49 - compared to an MOT test top limit of 200.

The bottom line is that it's just an annoyance and the engine is running fine (and cleanly). My car has a 200 cell sports cat - this together with the precat and standard backbox mods was worth 8hp. The cat cost £170 - the rest was just time spent.

The risk of the light coming on is highest if the wash coincides with running at cruise power.

Maybe the answer is just to go flat out everywhere !. 

does it go off by itself after time (5 cycles) or do you have to reset it?

#2177

Mine has never reset itself - I don't think it will, even after 5 cycles.

So far I have reset it (twice) with a Tech 2 (Vauxhall's service tool). Now I know it's nothing to worry about I've given up, might just remove the bulb.

The "proper" fix would be to increase the parameter used by the EMS to set the Pre / Post cat Lambda differential - someone need to work out how to do this.

I'm not particualrly keen on the Lambda decoy device - although they do apprear to stop the light coming on. The above fix would be better - and perserve the functionality designed into the EMS.

What sort of cat have you got and where from?

Weber Alpha - www.Webcon.co.uk

I have something new on this. I am running a janspeed sportscat and backbox and I get the CEL light on after a couple of miles. I was wondering whether this is a result of the cat efficency or has other reasons. We found out today that it has nothing to do with cat efficiency but with the geometry of the VX220. In idle operation the open exhaust inhales oxygen through the pipes, which finally makes it to the second oxygen sensor, which then senses that not all oxygen has been burned and gives a cat malfunction signal. I have measured a lambda 1.2 in the backbox with both pipes open and after closing one pipe I read lamda 1.02, which is the desired value. The cel light issues are a result of the open backbox systems and the short distance to the second oxygen sensor. What is the solution? I will get a system installed, which will close one of the two pipes unless I am in boost mode. This will also help to reduce noise during cruise mode. #2177

What is the solution? I will get a system installed, which will close one of the two pipes unless I am in boost mode. This will also help to reduce noise during cruise mode.

#2177

Install a CEL light illiminator. See here: http://www.vx220.org...&hl=lambda&st=0
It works fine for me and I have no cat at all.

I have just finished installing the O2sim on my supercharged speedy... pretty easy installation, as long as you know the cable codings... amazingly, the car is now noticeably different an annoyoing flat-spot at 3750rpms that was bugging me is now totally gone.... ...and the car seems to pull stronger than before, more linear delivery and stronger punch...I g-forced 1000mt in 24 secs flat... also I used to have quite white tailpipes, the classic sign of too lean fuel mixture.... something that never made sense, considering the two extra injectors from the supercharger... I now bet that the working lambda was reading the extra fuel as too much, hence signal the ECU to lean down everything.... now that is tricked to read perfect fuel, all seems working top-notch...and the pipes immediately turned darker, as it should be... oh, btw the MIL light never came up in the first place, I followed Cicastol suggestions to connect the ground O2 wire cable straight to the frame instead as they tell you to do, to the lambda ground...and that should fix the mil light for good... to Cicastol for his precious phone-advisories... here is the lil O2sim in place...the toffee-looking box overall quite chuffed by its unexpected effect...

Edited by Ricky2772, 15 June 2005 - 08:00 PM.

TBH Ricky it doens't sound like the car was mapped right in the first place.

TBH Ricky it doens't sound like the car was mapped right in the first place.

I never understood it exactly...after Hitec mapped it , it was like that already, pulling stong anyway, dynoed at 217hp, but after few months the MIL light would come up here and there, sometimes the fan would kick in at start up... , and the exhaust color would switch from super-black to grey-white.... now all seems fine....could it be that the lambda itself was broken, giving erratic readings?!?

Ricky or griffo, could you post a pic of how you have conected your o2sim?? I have one, but have not got it to work propertly, get the CEL back after about 170km every time

sorry dont have a piccie of the connections... do you see the black wire in the picture running off the o2sim? I screwed it directly on the metal frame, and not to the lambda ground. that is the key to make it work, according to cicastol. the two lambda grounds, first white and black, stayed the same. you connect the white sim cable to the grey wire ( sensor) and the red to the (second white, all three spliced ends togheter)

This is how i have it conected now. I have conected o2sim gournd to engineground (big white wire) to avoid the 10k ohm resistence i had before. o2sim red is spliced in to o2sensor white, one of them, hopefully +12v but it´s here i think i may have got it wrong. With one of the white is +12v? the outside one or that next to black signal??

. With one of the white is +12v? the outside one or that next to black signal??

+12V heater is the outside white if i remember well!!

P.S. to clear the things i will make some photo of my working connections

Edited by cicastol, 16 June 2005 - 10:17 AM.

+12V heater is the outside white if i remember well!!

no!! I made that mistake yesterday...the first white in line is the ground, so leave it alone.... the heather is the second white.... once that was hooked up, the green led started to blink...

My led starts to blink whith egnition on, but I still got CEL today after 100km driving

Just checked my connection,mine are the only working and tested nearly 5000Km without cel light come on !!! Attach the RED O2sim +12V to the EXTERNAL white heater,all spliced togheter,Black O2sim ground to chassis,white O2sim signal to black lambda,leave the lambda signal alone wrapped with tape. If you attach the +12V to the inner white,when the engine is running the voltages drop below 6V ........ and after +- 100km mil came on again!!

I´m going for a 900km drive next week, hope it works...