02 sensor addition to euro w/usa engine

914efi · 11-28-2008, 01:11 PM

I'm putting an '86 US engine into my '82 Euro car and need to know how to connect the 02 sensor. Is it as simple as finding the correct pin on the ECU plug and adding a wire there? I plan to use the '86 computer.

Thanks

914efi · 12-02-2008, 04:56 AM

Bump and update. I posted this over the TG weekend, so maybe not many people around.

I traced wires on the '86 engine harness,
#1 on the 02 connector goes to #24 on the ECU plug (green),
#3 on 02 goes to #19(brown yellow) on the ECU
#2 on the 02 goes to #4 on a 14 pin plug, this must be power to the 02?

On my '82 the #24 pin is vacant on the ECU plug, but #19 pin has a wire already, not sure where it goes yet.

Since I also need to add a circuit for power going to the old style aux air regulator, maybe I can use the same source to the 02 sensor.

Thanks for any insight, and maybe opinions on the need for the 02 sensor. I was thinking it would help fuel mileage, but I know there are chips that take it out of closed loop all the time.

HondaDustR · 08:33 AM

If you're using the 86 motor with the 86 DME, the you don't need the auxilary air regulator. you'll need the wiring for the idle stabilizer valve if you are reusing the old 82 harness.
Here's the complete pinout for the DME in case you don't have it. http://www.frwilk.com/944dme/connector.htm

the o2 sensor can help fuel milage if it runs rich to begin with, but you may find it runs better without it as long as everything is in good working order. The DME does run in open loop straight from the maps when the sensor is disconnected. It's just there to be the last line of compensation if the fuel mixture is off due to dirty injectors, slightly misreading sensors, bad fuel, small vacuum leaks, stuff like that. Then you can tweek the maps with the FQS.
On mine I've found the best compromise is to run the FQS in position 2 (-3% fuel from the base map) and have the O2 plugged in. It ran pretty well before it got cold with the sensor disconnected, but i think the air temp sensor ran out of response at the cold temp (either just old, or just the way it is) and the part throttle maps below about 4000 got too sluggish and lean. WOT maps are awesome, though. With the sensor plugged in, at least it richens up the part throttle, but leaves the WOT alone. Only downside is it idles rough when using the o2 sensor. Maybe adjusting the air bypass on the AFM would fix it, since the o2 sensor signals rock bottom lean on it's scale at idle and unplugged (measuring voltage from the sensor). Now if I could have the leaner WOT combined with the rich part throttle maps...

914efi · 12-02-2008, 08:41 AM

Thanks for the input.

I was pretty sure that I would not be able to use the '86 wiring and would need to put in the old style aux air unit. Maybe I should trace those wires as well, but I could see this getting complicated due to the AC idle control also being different.

I'll check the frwilk stuff.