[rfmaster]

Originally Posted by pancake

Since I do not have to worrie about emission control, do I NEED an Air diverter valve?

In my orignal post, question #1, for the N/S switch, rfmaster said to leave it open. Can you elaborate? open=not hooked up at all?

If I go with a stock harness, $ is always an issue, for the wires I dont use do I just cut them off?

I do have headers on my blazer. So I will need a 3 or 4 wire o2 sensor. I will also need to weld a bung into the header. I have read keep it within 12" of the head...is this correct?

Can you please explain how to"wire a simple relay controlled circuit to turn heater when ignition is on"?
I am no electrican but did google relay info and have a very basic understanding. Please correct me if I am wrong, but there are always open or always colsed relays....and a relay is just a switch operated by a current?? correct?

N/S - Lieve end of that wire unconnected ECM Pin-B10 (Orange-black wire). In automatic equipped cars this line is grounded via P/N when transmission is set in Park or Neutral. This is done to compensate commanded engine idle speed in drive by about 50 to 75 depending on operating conditions.

If you go with stock harness - I would first lay out and id all connections - see my early post elsewhere in this post. IMHO I do not like to cut, but you can choose to remove unused circuits.

O2 positioning was critical for couple of reasons. First the O2 must be heated to about 600F to operate. Placing it further down stream tends to keep it below 600F. Heated sensor gets around this placement requirement. Another reason for keep O2 closer to the engine is what is known as transit response time. ECM operates close loop feedback system which takes into account response delay times. I can go on further into control system theory, but ideally observation points need to be within near proximity of the process to keep close loop operation stable.

I'll post simple relay circuit schematic - it is a bit late tonight.

Automatic calibration or broadcast code BCC (EPROM) can be easily adapted to manual transmission duty. As is automatic calibration is not ideal, but it will get you going. There are several calibration tables that must be changed to make manual transmission operation smooth. This is another subject area that you'll have to research. For now hunt for a 350 based BCC 1227747 ECM as your starting point. .

Relay allows small control current to control large load current.

//RF