Engine management system failures - advice sought

[Davidm1600]

Hi all

Right so only just this week we replaced Lambda sensor No. 3, I am pretty sure it was one of the top ones, on my JTS 156 Sportwagon.  And yet a day or two later, the bloody alarm and light came back on again, flashing and beeping.  The car seems to be partly driving ok, although I do notice that when first off driving it feels like it is surging and then loosing a little power before surging again, if that makes sense.  Basically it doesn't feel smooth in power delivery.  Perhaps even a suggestion of hesitation.

So the question is do I need to replace potentially Lambda sensor No4 or as was suggested to me yesterday by our local Alfa service agent/dealer is it perhaps the catalytic converter or coil packs, which could lead to cat failure anyway which is the problem.  His best guess without having the car on the computer was from his experience it is likely to be the cat.  He also mentioned that a factory cat costs around $2800 while a generic brand one is about $1400.  Ouch either way.

The next question is has anyone gone down the route of using a second hand cat, say off a crashed or otherwise written off JTS ?  If so how do you know if a second hand one will be ok, and what sort of $ could one get one for ?

I only ask as $$ are somewhat tight for me at the moment, and hence need to find the most cost effective route to getting this problem finally sorted out.  I don't want to waste money/nor spend it where I don't need to. 

If I can get a good second hand cat, also does anyone have some helpful suggestions as to where from.  I havn't yet checked out overseas as to possible suppliers (eg EB spares) yet, and perhaps the cost might be better from there but then again there is also the freight cost which might make it not worth it.

I really don't wish to drive the car until I can this sorted, so any help/ideas would be appreciated.   Dave

[colcol]

I would get it hooked up to a Alfa computer to find out what the problem is, Lambda sensors are not too expensive, but i wouldn't want to replace them for no reason, some manufacturers replace the Lambda sensors as part of a 60,000 4 year service, if you are going to replace the CAT, then make sure its faulty, unless you can get a second hand one for $200, i wouldn't get one, as like yours it could be nearly worn out, try all the usual suspects, such as EB spares, the Alfa Workshop, but poastage will be the killer, a non genuine CAT might be the go, same as the coil packs, find out if they are faulty before discarding them, locally they are about $400 each, cheaper from the UK, or you could look at non genuine coil packs as well, Colin.

[wankski]

as per colin, you need to code it... there are two different errors, one for lambda readings, and the other for cat efficiency... so it will tell you...

it also says which lambda is at fault if any, so no need to guess...

other issues like poor grounds can cause false coding.

where are you? if you are close to bentleigh or parkville vic, i am willing to code it up for you if you wish... if you're interested i can show you how to have diag all for yourself too! if you have a windows laptop it costs like $70, and you too can have the ability to check your car - clear codes etc...