David sent out a message with the bypass prototype for the CE light, if everything else is fine but you keep getting a "Secondary air injection message" P0410 or similar as in my case and it doesn't go away probably there's is carbon build up as it was well discussed. This circuit will just short the O2 sensors while the computer checks it at warm up for a short time, and so it will "think" it's fine. Since the OBD1 993's (pre-96) usually don't get the message it's probably due to the fact that the software is not that picky. The final solution is open up the engine and clean it but it will come back up after some 40K miles ... so leave it for when some engine work is due and meanwhile bypass it with this. As I had on some of my other little diatribes this whole Secondary air thingie is not even present on Euro cars so bypass the bloody thing.
I cannot find a good set of connectors to make it a Rennlist-type mod i.e. you can put it on and then take it out with no traces of it so that's the little hold up I was looking for an extra set of O2 connectors but they come along with the sensors.
Anyway this is the circuit (try it at your own risk), the gray wires
are common and it has some bias voltage(0.8V or so)
You can easily spot the sensor connectors, the relay is inside the box with
the high voltage label, in the engine compartment(I haven't cleaned my car
for a couple of weeks when I took the shots so don't mind the dust),
a closer view of O2 connectors is here
to get to the relay unscrew the 3 screws as shown here
and you can easily pull it out, it's number 2 as indicated in the plate of the
box and then you find pin-5
make sure the key is in the off position while around here so you don't get
a little voltage on you.
Very simple an easy to install/try, A mod suggested by david was a 4 transistor layout and shorting the 0.1k resistor, I will try the basic first and then go from there, as I said my main holdup is finding a good set of connectors but I thought some of you might like to take a look.
Again try it at your own risk and be careful, I'll try it out and report if I get the same results as David who doesn't get the CE while his circuit is on and it comes back when it's taken out.