I have had a Mongoose de-cat fitted to my STi recently. The engine management light came on after a month or so when I was just tootling about. I plugged it in at the local garage and it was Bank A (lambda sensor) and the camshaft sensor. Changed the sensor and it reset ok. I got in it the next day and the light was off and it stayed off when I was giving it some death and it went on again when I was in town again.

Ive tested it a few times, giving it some beans leaves the light off and cruising the country side puts it on. Its obviosly burning clean when its going for it. I have a blank for the lambda sensor hole and am asking what to do with the sensor? Snip it or just leave it hanging? And has anyone else had this problem.

The car is standard apart from a panel filter, de-cat and Full stainless exhaust.
Cheers folks.

 

This has happened to me in my 2001 WRX . the owner of the garrage showed me the cataloge and it clearly stated that the de-cat down pipe would bring on the CEL and read the code for lambda in newage cars .

1 week after fitting it came on they read and cleared the code just to be sure but told me that only a remap or small ressistor(£2) would stop it happening again .

 

A CEL fix is available i.e. you can pull your ROM and remove this from the image and stop it happening. That is...unless you are already mapped using EcuTek. Head over to openecu.org :: View topic - permanent cel disable and do a search for CEL fix.

 

Two years ago I fitted a catted down-pipe, light comes on usually if I'm on a motorway cruise about 75-80 mph.

Never when giving it plenty....

So I finally re-mapped it to 340+ bhp, you know it makes sense, yes I am a very old git and my insurance don't care !!!


Unless I want a 2.5 conversion....

So ignore it or re-map it soon.... Dunx

 

Thanks guys. The only reason that I am worried is that with the light on all of the time and something magor goes **** up then I wont know. thanks again.

 

by the way craigie, do you happen to know the size (resistance) of the resister required. that would be handy. cheers

 

Not sure 2.2k rings a bell ,if you do a search for "CEL fix " or something similar i'm sure you will be able to find out

 

Thanks. Can anyone confirm 2k2 or any other solution?

 

Personally I'd have the car re-mapped to unleash a few more horses and get rid of the P0420 de-cat CEL.

The 2.2K ohm cel fix is for the CEL associated with removing the EGT sensor in the WRX (the STi does not have an EGT).

The newage ECU expects to see a fluctuating value from the rear 02 sensor (lambda) so a CEL fix with a resistor may not be 100 percent reliable.

The other thing is that camshaft position sensor errors are common for the Bugeye at high revs LOL

Shaun

 

I'm confused. Are you saying that you have fitted a new downpipe and have blanked off the lambda sensor bung and left the lambda sensor hanging on the end of the wire ?

I've had decatted classic and newage sti cars and never had a cel come on for the lambda sensor.

Your car will use the signal from the sensor in closed loop to keep the afr around 14.7:1, but won't use it when you are booting it as it will be in open loop.

 

I guess we are talking about the rear 02 sensor in the downpipe which checks for cat efficiency and NOT the front Lambda sensor which the ECU uses for fuelling.

De-cat a newage and the ECU will flag up CEL P0420 (catalytic converter below efficiency) because the rear 02 sensor reads out of normal range.

CEL fixes are available but as mentioned this particular CEL is best ECuTeK mapped out

This is how I was reading the thread

Shaun

 

The CEL fix for the rear O2 sensor fault caused by removing the cat from the downpipe is available from Hayward and Scott for £10. Give them a ring to order. Stainless steel exhausts manifolds and headers from Hayward and Scott Comes with installation instructions.

The CEL fix for the up-pipe is a 2.2k Ohm resistor, but as you have an STi then this DOESNT apply to you.

Either remap or buy a CEL fix from H&S.

 

Hmmmm well first things first, DONT RAG YOUR CAR, words of warning.
New age STi's dont like to be decatted, it causes boost spikes which in turn can cause det, which in turn kills your pistons and thats not good as it causes little bits of metal to fly around your engine and kill it also, rebuild costs of about 2.5-4k.
You need the following soonest:-

Remap

Cost of about 650+ vat.
Cheaper than an engine rebuild though what damage may have been done so far.....

Tony

 

For a cheaper remap you can go the OpenECU route. Have a chat to snet member JollyGreenMonster as I've read he does non-Ecutek mapping. I believe OpenECU maps are available for around 300.