thats the O2 sensor, you can probably only see one wire because they are inside the insulation, follow the wire around the engine bay - you'll find the connector where the haynes manual says, simply unclip and pull apart, IIRC 22mm spanner to undo it out of the manifold.
Sounds like someone has already been playing with it then. Possible corrosion in the bullet connector is screwing up the signal, but you'll have to replace it anyway..
the plug up at the firewall ( bulkhead ) is maybe 2" across, just two wires, generally found behind the brake master resevoir, the other end of this will go into the wiring harness that is draped around the offside suspension turret that then goes over the coolant header tank and through the bulkhead into the car, see if you can find it that way.. if not grab the sleeve, slide your hand along it until you can't move anymore and wiggle it, you should see the plug floating about now. It may help to remove the sealing strip from the scuttle and lift the plastic lip up, underneath this is all the wiring, you could even unclip all of this to locate the plug.
I'll give it another look. Could a faulty O2 sensor cause rough idling and hesitant acceleration?
yes, but could be TPS, Air idle valve, air mass meter, plugs, leads....
is the engine management light on ? read the codes off of it and report back.
Code 13. I've only got the codes for the Simtec system, are these the same? The initial code (12) is the same, so I get 12-12-12 13-13-13 repeated.
I might try disconnecting the lead and running for a few seconds. This should re-light the ECU fault light and still give code 13.
Pete
13 is, IIRC open loop, i.e. O2 sensor shagged so you are on the right track.
Cavaliers used both single, 3 and 4 wire sensors, Sounds, from your earlier post, as if yours is just a single wire Lambda sensor, Not very expensive :-))
Regards, Graham
IIRC, multec is normally single wire. Expect to pay ~£30
The Dervboy
Vauxhall dealer £108, motor factor £26 (but doesn't have the connector). No-brainer.
Next questions:
How the hell do I get the old one off? It's kinda stuck. I've tried brute force with cold, warm and hot engine but can't even shift it a tiny bit. Don't want to WD it in case it catches fire.
What grease do I use for the new one?
Ta
Pete
Firstly beware that they often seize really badly, and when you do get them to move they often wind out the thread, so be prepared to remove the exhaust downpipe and either have a new boss welded in, or replace it with a 2nd hand one.
The best way to remove I find is to cut off the wire, use a well fitting 6 sided deep socket, then heat up the sensor if it safe with a blow torch (oxy acetelene we use) to deep red heat then quench with plenty of water. Repeat if necessary.
A -small- smear of copper ease, make sure you keep it well away from the sensing element though.
Tim..
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