Remembering why I
dislike working on
AO Silver Member
Join Date: Sep 2001
Re: Lambda sonde error diagnosed and changed, problem remains ...
It's gotta be worth a try if it has a heated lambda probe. (I don't know for sure that an 8v does have, but strongly suspect it will).
It's essential the probe gets hot in order to work. If it cools off (low revs/load and heater fuse gone), it goes effectively open circuit, the ECU detects this and substitutes a default value. Once you put your foot back in it, the added exhaust flow heats it up again and all is well.
Earlier non-heated systems had the probe close enough to the engine that the heat from passing exhaust gas was always enough to keep it hot once the car had warmed up a wee bit.
The other fairly common problem in this area seems to be connection problems between probe and loom. Sometimes caused by water ingress, sometimes by iffy workmanship.
The normal fuse is a 7.5A I think, but a 10A is fine. Swap the relay as well....