Alfa 33s 16v QV P4 (Forza)

Andrei.QV

New Member
Messages
26
The car seems a lot torquier with this AFM than the other 2 without flap (the 3 digit number is 955 by the way). I'm trying to make my cat 33, non-cat. The question is, if I remove the yellow relay and do an ecu reset will it run the non-cat mapping?
 

33bits

New Member
Messages
17
You don't need to do an ECU reset, these 142 ECU's arn't clever enough to need that. I've de-Catted my 33, I fitted a standard exhaust system & then removed the fueling bridge wire that tells the ECU which octain petrol is needed. All is fine. I'll get a picture on here tonight of the orange block where the wire to be removed is.
 

33bits

New Member
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17
Thanks Nick for putting these pics on. That wire looks like a tacky bodge but is actually an original Alfa fitment! As far as I'm aware it tells the ECU what RON fuel is being used, without a cat & lambda sensor that info isn't needed. When I de catted mine it was overfueling until I removed this wire.
 

Andrei.QV

New Member
Messages
26
So basically if I remove it its all good? Or do I have to put the wire like this so I have 98 ron mapping?
 

33bits

New Member
Messages
17
Just remove it. As long as you don't have any lambda sensor wired up and this little wire is NOT present you will be fine. No ECU re tuning is needed.
 

Andrei.QV

New Member
Messages
26
Another question, the lambda has only one wire ? because where the wire connects to the harness there is another connector which remains empty(same connector as injectors or temperature sensor) is it possible that my lambda is missing one connector?
 

33bits

New Member
Messages
17
No you should be fine. There are two (poss 3) different types of lambda sensors & both have different connections. The most common has 2 plug, (a single wire plug & a 2 wire). It sounds like you have the other type. But not an issue either way, as long as you don't have any exhaust probe wired up then the ECU cant get confused with a reading. Remove this little wife in the above picture, disconnect the lambda hey presto.
 

Andrei.QV

New Member
Messages
26
It seems I have the 2 connectors type but one of them was eaten by my dog (while the exhaust manifold was in the courtyard). I have to say, I knew the lambda trick for a while but my car just works a lot better with the lambda connected, the engine has a smoother sound too.
 

33bits

New Member
Messages
17
Yep I know exactly what you mean. Keep it connected if you prefer. It will affect the way the ECU sorts out the fuelling. If you have a cat then you have no option but to have it connected. It always helps to make sure the temp sensor that screws into the n/s throttle body is healthy too as that is hard wired directly into the ECU & that controls the air/fuel mixture too. When that sensor breaks down it makes the ECU go into default mode & it will over fuel.
 

Andrei.QV

New Member
Messages
26
I think the temperature sensor or wires are not working properly, my car doesn't seem to pull right, mechanically the engine is new with non-cat camshafts (which are more agressive) and lighnted crankshaft and ported heads it should make a lot more power but the car feels weak, its even hard to move it from stand still, I have to use a lot of throttle. Could it also be because Ive used denso ik20 (i think) spark plugs? Could the spark plugs make such a difference? What else could lead to default mode of ecu and how can I know if it is default mode?
 

33bits

New Member
Messages
17
Well...... I personally don't rate those plugs, I've tried a few various options & now I always use NGK BCPR6ET. The Alfa ignition system really likes NGK plugs. Ironically I changed my 33's plugs yesterday. If the ECU goes into default mode you will know it's running rich, when mine did it you could smell petrol coming out the exhaust. It's always worth fitting a new temp sensor & those spark plugs. I've got new sensors in stock if you need one.